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Evaluation of brewers yeast (Saccharomyces cerevisiae) as a feed supplement for hybrid striped bass (Morone chrysops×M. saxatilis)
Abstract
Two separate feeding trials were conducted to evaluate graded levels of dried brewers yeast in the diet of hybrid striped bass. A basal diet was formulated to contain 40% protein, 10% lipid and an estimated digestible energy level of 3.5 kcal/g. In Trial 1, three incremental levels of dried brewers yeast (1%, 2% and 4% of diet) were added to the basal diet in place of cellulose. In Trial 2, the same levels of brewers yeast were added to the basal diet, but menhaden fish meal and menhaden oil were adjusted to provide isonitrogenous and isolipidic diets. Each diet was fed to three (Trial 1) or four (Trial 2) replicate groups of juvenile hybrid striped bass twice daily at rates approximating apparent satiation for 6 or 8 weeks. After the second feeding trial, a Streptococcus iniae bath challenge was executed to test the effects of diet on disease resistance.
... Many dry yeast products have been evaluated as dietary elements for several aquaculture species (Jones et al., 2020), including red drum Sciaenops ocellatus (Rosales et al., 2017), Pacific white shrimp Litopenaeus vannamei (Achupallas et al., 2016), Nile tilapia Oreochromis niloticus (Peredo et al., 2015), rainbow trout Oncorhynchus mykiss (Hauptman et al., 2014;Sealey et al., 2015), hybrid striped bass, Koi carp Cyprinus carpio (Korkmaz and Cakirogullari, 2011), Jian carp, Cyprinus carpio var. Jian (Yuan et al., 2017), and female white bass Morone chrysops × male striped bass M. saxatilis (Gause and Trushenski, 2011;Li and Gatlin, 2003, 2004, 2005. In some studies, the dry yeast products were added to the diet to serve as providers of various immunostimulating compounds such as β-glucans, nucleic acids, as well as mannan oligosaccharides (Li and Gatlin, 2003, 2004, 2005Peredo et al., 2015); whereas, a few of them were conducted to assess dry yeast as an alternative protein feedstuff to replace fishmeal in the diets (Gause and Trushenski, 2011;Hauptman et al., 2014;Rosales et al., 2017;Sealey et al., 2015). ...
... Jian (Yuan et al., 2017), and female white bass Morone chrysops × male striped bass M. saxatilis (Gause and Trushenski, 2011;Li and Gatlin, 2003, 2004, 2005. In some studies, the dry yeast products were added to the diet to serve as providers of various immunostimulating compounds such as β-glucans, nucleic acids, as well as mannan oligosaccharides (Li and Gatlin, 2003, 2004, 2005Peredo et al., 2015); whereas, a few of them were conducted to assess dry yeast as an alternative protein feedstuff to replace fishmeal in the diets (Gause and Trushenski, 2011;Hauptman et al., 2014;Rosales et al., 2017;Sealey et al., 2015). However, while the total replacement of fishmeal by dry yeast was possible in some fish species such as sea bream, Sparus aurata (Fronte et al., 2019), only partial replacement was possible in other species where higher dietary levels of yeast products led to reduced growth and compromised health status of the fish, as was the case for koi carp (Korkmaz and Cakirogullari, 2011), hybrid striped bass (Gause and Trushenski, 2011), red drum (Rosales et al., 2017), rainbow trout (Hauptman et al., 2014), carps (Korkmaz and Cakirogullari, 2011;Yuan et al., 2017) and Pacific white shrimp (Achupallas et al., 2016). ...
... The results of the present study demonstrated that 100% of fishmeal could be replaced by DY-Pro in Nile tilapia diet. These results are consistent with previous findings, which showed that Saccharomyces cerevisiae yeast products used at level as low as 2% in the diet could enhance growth, have beneficial non-specific immunostimulating effects and contribute to maintaining good health status of fish (Li and Gatlin, 2003, 2004, 2005Rosales et al., 2017). Although a disease resistance test was not performed in this study, it could be argued that the inclusion of 2% DY-Pro in the diet at the expense of fishmeal likely had a positive effect on nutrient utilization, considering the fact that there were no significant differences in growth and gut histology between the control and the DY-Pro2 diets; whereas, lower feed intake and better FCR were observed with DY-Pro2 as compared with the control (DY-Pro0). ...
There is a growing concern about the use of fisheries-derived proteins in aquaculture. This study was conducted to investigate the effect of either partially or totally replacing fishmeal (up to 15% of the diet) by the inactivated dry yeast product DY-Pro in Nile tilapia Oreochromis niloticus diets. The DY-Pro replaced 0% (DY-PRO0), 2% (DY-PRO2), 5% (DY-PRO5), 25% (DY-PRO25), 50% (DY-PRO50), 75% (DY-PRO75) or 100% (DY-PRO100) of the protein provided by fishmeal in seven isonitrogenous and isocaloric experimental diets, which were fed to the experimental fish (initial average body weight 11.33±1.65 g) for 12 weeks. At the end of the experiment, the graded replacement of 2% to 100% of fishmeal protein by the DY-Pro did not significantly (P < 0.05) affect fish weight gain or gut length and weight, but linearly (P < 0.05) improved feed and nutrient utilization. Moreover, the DY-Pro did not have any negative impacts on the gastrointestinal tract as shown by histopathology. There were no pathogens or signs of significant metabolic or toxicant-related disease in the epithelium. Results showed that tilapia given diets containing DY-Pro consumed less feed to achieve the same weight gain as tilapia given fishmeal-based diets. Overall, the DY-Pro is a good feed ingredient, which could totally replace fishmeal in Nile tilapia diets and possibly lead to reduced feed costs.
... Dietary S. cerevisiae supplementation can effectively reduce the requirement of protein from the animal source (Oliva-Teles and Goncalves, 2001). Dietary incorporation of S. cerevisiae boost up the production and feed efficiency of hybrid striped bass, Morone chrysops × M. saxatilis (Li and Gatlin III, 2003;Li and Gatlin III, 2004;, Nile tilapia, Oreochromis niloticus (Lara-Flores and Olvera-Novoa, 2003;Abdel-Tawwab et al., 2008), hybrid tilapia, O. niloticus × O. aureus (He et al., 2009), gilthead seabream, Sparus aurata (Salnur et al., 2009) and rainbow trout, Oncorhynchus mykis (Molook et al., 2009). Probiotics incorporated into the diet can enhance the growth and develop the gut environment and wellbeing of cultured aquaculture species (Talpur et al., 2012;Reda and Selim, 2015;Ramos et al., 2017). ...
... Among this wide range of probiotics, S. cerevisiae can be effectively applied as probiotic to boost up aquaculture production (Lara-Flores and Olvera-Novoa, 2003;Abdel-Tawwab et al., 2008;Chiu et al., 2010). The application of S. cerevisiae in aqua feed industries is increasing continuously for having the capacity of immune response enhancement (Li and Gatlin III, 2003;Li and Gatlin III, 2004) and potential influence on gut microbial communities of host (Tovar-Ramírez et al., 2002). ...
... The current experiment revealed that increased level of S. cerevisiae supplemented diets enhanced the production and feed effeciency in rohu, L. rohita. Several studies have been displayed that diets having baker's yeast improved the production of fish, including the Nile tilapia, Oreochromis niloticus (Abdel-Tawwab et al., 2008), hybrid striped bass, Morone saxatilis × Morone chrysops (Li and Gatlin III, 2003;Li and Gatlin III, 2004), gilthead seabream, Sparus aurata (Salnur et al., 2009), Statistical significant (p < 0.05) variations among different groups in a row are indicated by different alphabetical superscripts. The values are articulated as mean ± SD (n = 6). ...
Probiotics play an important role as bio-friendly substances in ensuring the sustainability and profitability of aquaculture. In the present study, we examined the effects of probiotic brewer's yeast, Saccharomyces cerevisiae on growth, feed utilization, hemato-biochemical indices, intestinal microbiota and intestinal morphometry of rohu, Labeo rohita. A trial of 90 days was conducted in which rohu fingerlings were fed under four different treatment groups in aquaria, receiving S. cerevisiae at 0, 1, 2 and 4 g/kg diet, respectively. Growth parameters (weight gain and specific growth rate), feed utilization (feed conversion ratio and protein efficiency ratio), hematobiochemical indices (hemoglobin, red blood cell, white blood cell and glucose), intestinal microbiota (total viable, lactic acid bacteria and yeast count) and intestinal morphology (villi length, villi width, crypt depth, thickness of villi wall etc.) were analyzed at the end of feeding trial. The results demonstrated substantial development in the growth performance, feed utilization and hematobiochemical indices in rohu fed probiotic incorporated diet compared to control diet. There were noticeable variations in intestinal microbiota and intestinal morphology between the treated and control diet fed groups. These results revealed that S. cerevisiae has a potential influence as an essential probiotic to improve the digestion, absorption, assimilation of nutrients through the improvement of gut microbiota and morphometry of L. rohita. Thus, S. cerevisiae can be effectively recommended as an important growth promoter for rohu.
... Saccharomyces cerevisiae is not only rich in protein and amino acids but also contain various immune-stimulating compounds, such as β-glucans, mannan oligosaccharides, chitin, and nucleic acids (Sheikhzadeh et al., 2012;Shurson, 2018). When S. cerevisiae was included in feeds, the growth and immune responses of Nile tilapia (Oreochromis niloticus L.; Abdel-Tawwab et al., 2008), rainbow trout (Oncorhynchus mykiss; Tukmechi et al., 2011), hybrid striped bass (Morone chrysops × M. saxatilis; Li and Gatlin, 2003), red drum (Sciaenops ocellatus; , zander (Sander lucioperca; Jarmołowicz et al., 2013), and roho labeo (Labeo rohita; Andrews et al., 2011) were significantly improved. Yeast was included in the Chinese Feed material catalogue in 2013, which means this organism is suitable for animal feed. ...
... Dietary supplementation with S. cerevisiae also reduced the CP content in the body of Nile tilapia (Hassaan et al., 2018), but increased CP contents in the bodies of galilee tilapia (Sarotherodon galilaeus L.; Abdel-Tawwab et al., 2010) and pacu (Piaractus mesopotamicus, Holmberg 1887; Ozório et al., 2010). Dietary supplementation with S. cerevisiae had no significant effects on the body composition of hybrid striped bass (Li and Gatlin, 2003), beluga (Huso huso; Hoseinifar et al., 2011) and rainbow trout (Barnes and Durben, 2010). Changes in lipid and protein contents in the muscle and body might be linked to changes in the synthesis and/or deposition rate of these molecules (Chang et al., 2017). ...
... Study has found that excessive plant protein in feed will lead to the decline of antioxidant capacity . As S. cerevisiae is rich in mannan-oligosaccharides, β-glucan, and nucleic acids, S. cerevisiae supplementation may increase non-specific immune enzyme activity in aquatic animals, including the hybrid striped bass (S. cerevisiae, 507.0 g/kg CP; Li and Gatlin, 2003), catfish (S. cerevisiae, 487.0 g/kg CP; Bu et al., 2019), and carp (S. cerevisiae, 560.0 g/kg CP; Yuan et al., 2019). In this study, intestinal CAT and LZM activity levels of Y0 group did not differ significantly compared with the FM group, and SOD activity was significantly reduced after E. coioides was fed a diet supplemented with S. cerevisiae extract. ...
Six iso-nitrogenous and iso-lipidic experimental diets were formulated to evaluate the effects of Saccharomyces cerevisiae extracts, as part of a low fishmeal diet with a complex plant protein source, on the orange-spotted grouper (Epinephelus coioides). In positive control group, fishmeal was the only protein source (FM). The negative control group (Y0) was fed low amounts of fishmeal, and plant protein was used as the protein source. The other diets were supplemented with Saccharomyces cerevisiae extract: 1 g/kg (Y1), 2 g/kg (Y2), 5 g/kg (Y5), and 10 g/kg (Y10). The Epinephelus coioides were divided into six groups, with three replicates per group and 30 groupers per replicate. The experiment lasted for 56 days. The results showed that there was no significant difference in weight gain rate and specific growth rate of FM, Y0 and Y2 groups (P > 0.05). In foregut, mucosal folds length in Y2 group was significantly greater than that in Y0, Y1 and Y10 groups (P < 0.05). The muscle thicknesses of foregut in Y2 and Y5 groups were significantly higher than those in other groups (P < 0.05). The muscle thicknesses of midgut and hindgut in Y2 group were significantly higher than those in Y0 group (P < 0.05). IL-1β and TNF-α in Y1 group were significantly downregulated compared with Y0 group (P < 0.05). After Vibrio harveyi challenge, survival rate in Y1 and Y10 groups was significantly greater than that in Y0 group (P < 0.05). These results indicated that compared with the negative control group, the addition of 2 g/kg S. cerevisiae extract could increase the mucosal folds length of the foregut, and the muscle thickness of the entire intestine, and maintain the growth similar to that of the positive control group. Adding S. cerevisiae extract to feed may improve the immune capacity of E. coioides, but the improvement was not obvious under the challenge of V. harveyi.
... S. cerevisiae merupakan imunostimulan alami dan juga berperan sebagai promotor pertumbuhan. Li et al., (2003) menyatakan bahwa penambahan ragi roti dapat meningkatkan pertumbuhan karena ragi roti mengandung nukleotida. Ragi roti mengandung nukleotida dalam bentuk basah purin dan pirimidin sebanyak 0,9 %. ...
... Hal yang sama juga dikemukakan oleh (Yin et al., 2006) menjelaskan bahwa mekanisme kerja imunostimulan dalam merangsang sistem imun adalah dengan cara meningkatkan Aktivitas sel-sel fagosit. Hal yang sama dikemukakan oleh (Li et al., 2003) bahwa ragi roti dapat meningkatkan aktifitas fagositosis karena bahan ini selain mengandung asam nulkleat dan nukleotida, juga mengandung β-glucan. β-glucan dapat meningkatkan aktifitas fagositosis dengan cara berikatan terlebih dahulu dengan molekul reseptor yang terdapat pada permukaan sel-sel fagosit. ...
... Peningkatan sel leukosit lebih banyak infiltrasi sel radang meluas pada epidermis. (Li et al., 2003) menyatakan bahwa ragi roti mengandung bahan-bahan yang berfungsi sebagai immunomodulator seperti nukleotida. Nukleotida adalah nutrient semi esensial dan bahan ini dibutuhkan untuk pertumbuhan dan perbanyakan sel organisme hidup serta mengoptimalkan fungsi-fungsi pembelahan sel termasuk sel-sel imun. ...
Barramundi (Lates calcarifer) is known as Sea bass with a selling price of Rp.75,000 - Rp.80,000/Kg consumption size. The purpose of this study was to determine the effect of the addition of bread yeast with different doses to feed on the growth of Lates calcarifer. This study uses an experimental method with a Completely Randomized Design (CRD). The treatments were P0=0% yeast, P1=0.5%, P2=0.10%, P3=0.15%, P4=0.20% yeast from the weight of the feed given. The results of the study are the bread yeast influences the growth of Lates calcarifer. The highest absolute weight gain in P4 treatment was 0.507 g. The highest absolute length increase in P4 treatment was 0.990 cm. The lowest FCR at perlakuan P1 yaitu 15,55. The highest survival rates are P2, P3, and P4 which is 100%. Erythrocytes with the highest total amount in P4 treatment 12,58x106 - 18,62x106 cells/mm3. Leukocytes with the highest total number in P2 treatment were 27,96x106 - 44,641x106 cells/mm3. Water quality parameter values in the maintenance media are in the range of requirements for Lates calcarifer cultivation. The conclusion of the study is the addition of bread yeast affects the growth of Lates calcarifer and the optimal dose that can increase the growth is 0,20%.
... The potential of yeast, Saccharomyces cerevisiae, as a probiotic has been investigated in many aquaculture species (Adel et al., 2017;Tovar-Ramírez et al., 2010;Navarrete et al., 2012). Yeast, a single-celled organism rich in protein, vitamins and minerals, possesses various immunomodulating compounds such as β-glucan, nucleotides, and mannan oligosaccharides (Li et al., 2005;Li and Gatlin, 2003;Oliva-Teles and Gonçalves, 2001). Past research indicates that various nutrients and immunostimulant constituents in yeast play potent roles in promoting growth performance, immune response and disease resistance in fish and crustaceans Zhang et al., 2018). ...
... (1-2%) as an immunostimulant to boost the immune response, or could be used at a higher level (25-50%) as a replacement to fishmeal without adversely affecting the growth of fish (Li and Gatlin, 2003). On the other hand, probiotics are beneficial bacteria associated with health and immune benefits for the host when administered in adequate numbers (Nayak, 2010a(Nayak, , 2010b. ...
This study was conducted to investigate the combined effects of probiotic yeast, Saccharomyces cerevisiae, and lactic acid bacteria, Lactobacillus casei on the growth performance, biochemical response, cytokine gene expression, gut histomorphology and microbial composition of juvenile barramundi, Lates calcarifer. Barramundi juveniles with an initial mean weight of 12.17 ± 0.15 g were randomly allocated into 8 tanks (300L) at a density of 20 fish per tank and fed either a basal diet (control), or the same basal diet supplemented with 1% of S. cerevisiae and 1% of L. casei, collectively termed ‘probiotic’, for 56 days in quadruplicate. Results indicate that dietary probiotic supplementation produced significant (P < 0.05) improvement in final body weight, specific growth rate and feed conversion ratio compared to the control. A significant increase in serum protein was evident in fish fed the probiotic supplemented diet, while none of the other measured blood and serum parameters were influenced by the probiotic supplementation. Probiotic supplementation also resulted in an up-regulation of immune responsive inflammatory cytokine genes (IL-10 and TNF-α) and exhibited a higher number of gut mucosal goblet cells and increased microvillous length. The sequence data of the distal gut showed significant positive influence of the probiotic diet on alpha-beta microbial diversities and decreased abundance of pathogenic Staphylococcus and Corynebacterium. These results confirm that the co-supplementation of S. cerevisiae and L. casei improved the growth, immune response and gut health by increasing the diversity of microbiota in juvenile barramundi.
... Besides its use as a protein source, brewers yeast at relatively lower levels (up to 4%) I also reported to act as an immunostimulant (Li and Gatlin, 2003). Even at this low dietary incorporation level, enhanced weight gain and feed efficiency compared to the control diet was observed in hybrid striped bass (Li and Gatlin, 2003). ...
... Besides its use as a protein source, brewers yeast at relatively lower levels (up to 4%) I also reported to act as an immunostimulant (Li and Gatlin, 2003). Even at this low dietary incorporation level, enhanced weight gain and feed efficiency compared to the control diet was observed in hybrid striped bass (Li and Gatlin, 2003). The beneficial effects of dietary supplementation with nucleotides is attributed to their effects as immunomodulators, particularly under stress conditions imposed by management or infectious diseases (Burrells et al., 2001a,b;Sakai et al., 2001;Li et al., 2004). ...
The aim of this trial was to evaluate the effect of dietary nucleic acids on ureagenesis and nitrogen balance in gilthead sea bream juveniles. For that purpose, 5 isonitrogenous (7.25% N) diets were formulated based on fish meal as protein source (FM-control diet) and to partially replace the fish meal nitrogen with two levels of nucleic acids (diets RNA1 and RNA2) or brewers yeast (diets BY1 and BY2). Each diet was fed for 10 weeks, to apparent visual satiety, to triplicate groups of 50 fish each with an average body weight of 12.7 g. Inclusion of nucleic acid N either as brewers yeast or RNA led to significant improvement of feed intake and growth, except for fish fed diet RNA2. There were no differences in final weight between groups fed the yeast- and the RNA-containing diets. Although there was an improvement of growth rate of fish fed the RNA or yeast containing diets, dietary nucleic acid supplementation did not have a clear N sparing effect. At the end of the trial there were no significant differences in whole body composition among groups, except for the lipid content which was significantly higher in fish fed the Y2 diet. Hepatic glutamate dehydrogenase activity levels did not differ among groups. Ornithine carbamyl transferase activities were very low in all groups, but appear to be induced by high levels of dietary RNA. Fish fed the yeast diets exhibited the highest arginase activity of all groups. No increase of uricase activities was observed in fish fed the RNA supplemented diets. Ammonia and urea excretion of fish fed the RNA-including diets was higher or significantly higher than in the other groups. Plasma urea levels were higher in fish fed the RNA diets than in the other groups confirming excretion data in that dietary nucleic acid influenced urea excretion through uricolysis In conclusion, substitution of N supplied by fish meal by that supplied by brewers yeast had a positive effect on growth performance of sea bream, while dietary nucleic acid supplementation did not have a clear N sparing effect. At a dietary level of 11.5% of RNA extract, there was no improvement of fish performance compared to the control, possibly due to an insufficient capacity of fish to degrade high levels of nucleic acid. Data on excretion and plasma metabolites strongly suggest that purinolysis contributes also to ureogenesis in gilthead sea bream.
... Frohn et al. showed that adding yeast extract to a rainbow trout diet can act as a source of high-quality protein (free amino acids and small peptides), therefore promoting the growth of rainbow trout [14]. Additionally, the addition of yeast extract can enhance the antioxidant and anti-aging capabilities of nematodes, subsequently extending the lifespan of the nematodes [15]. In addition to the mentioned nutrients, brewer's yeast is also rich in a large number of trace elements, is an inexpensive nitrogen source with good nutritional properties, and is a safe feed and food additive [16,17]. ...
Yeast extract serves as a source of nutritional components essential for human dietary requirements, feed formulations, and the vital growth factors and nutrients necessary for microorganisms. However, the production cost of yeast extract using cultivated active dry yeast is relatively high. This study aims to utilize the autolysis of discarded yeast post beer brewing to produce yeast extract. The concentration, temperature, pH, and time conditions are systematically optimized. It reveals that the yield of amino nitrogen and solids in the extract was increased by 3.3% and 20.9% under the optimized conditions (1.2% wall-breaking enzyme, 1% yeast extract enzyme, and a hydrolysis time of 24 h) than that of the documented 4.03% and 69.05%. Additionally, a comparative analysis with commercially available yeast powder demonstrates that the yeast extract derived from this study adequately fulfills the nutritional requirements for microbial growth. Hence, the utilization of discarded beer yeast presents an opportunity for the valuable reclamation of waste yeast, showcasing promising potential applications.
... The supernatant was separated, and its absorbance [or optical density (OD)] reading was taken at 540 nm. Absorbance was then converted to mg NBT diformazan/mL blood as in Li and Gatlin III (2003). ...
Iron (Fe) is a crucial mineral for the health of fish. The investigation explored the effects of two different sources of iron (organic and inorganic) and two levels (60 and 85 mg/kg) of Fe on the innate immunity, antioxidant capacity, and hematological responses of Nile tilapia. Fish with an average weight of 16.57 ± 2.25 g were fed three times a day for a duration of seven weeks. A total of 400 fish were distributed among 20 tanks, each with a capacity of 240 L and housing 20 fish. The experiment comprised five treatments, and the experimental design employed was a completely randomized design, which included the following treatments: a basal diet (BD) with no addition of Fe in the premix, 60 mg/kg Inorganic Fe, 60 mg/kg Organic Fe, 85 mg/kg Inorganic Fe, and 85 mg/kg Organic Fe. The results indicated that the use of organic Fe significantly improved the hematocrit levels and mean corpuscular hemoglobin. Conversely, the values of lysozyme decreased in fish that were fed with the organic Fe source. However, the hemolytic activity of the complement system and the production of the superoxide anion test exhibited an increase with the use of organic Fe. Furthermore, the fish that were fed with the 85 mg/kg organic diet demonstrated superior antioxidant responses. In conclusion, the inclusion of organic Fe at a concentration of 85 mg/kg was found to be more efficient for the growth of juvenile Nile tilapia.
... In various studies done in recent years, honey was noticed to increase the growth parameters in L. vannamei and O. niloticus Aryati et al., 2020), but whether honey can influence the immune system of the model organism is still unknown and requires further investigation. Li and Gatlin (2003) applied commercial prebiotic (Brewtech), manufactured from brewer's yeast by partial autolysis, in the diet of hybrid striped bass (Morone chrysops × M. saxatilis) and reported improved serum peroxidase activity when the initial weight of the fish is >50 g, while no change was observed when the initial weight is <50 g. ...
... Another advantage on the use of CFP in aqua feed formulation is the presence of yeast, up to 25%, and those microorganisms have shown the potential to produces several bioactive substances, such as glucans, enzymes, and vitamins to enhance immunity, growth and protection against pathogen infection (Ernesto Ceseña et al., 2021;Lara-Flores et al., 2003;Li and Gatlin III, 2003;Sarkar and Rao, 2016). Specifically in shrimp, supplementing yeast into feed has shown to improve growth, intestinal microbiota and immune response against Vibrio harveyi infection (Ayiku et al., 2020). ...
Two separate trials were conducted to evaluate the use of a novel Corn Fermented Protein (CFP) on growth performance and feed utilization of Pacific white legged shrimp Litopenaeus vannamei in out-door pond conditions as well an independent pathogen challenge (Vibrio harveyi) test under controlled conditions following an internal feeding trial with varying inclusions of CFP. In out-door ponds, the 12% inclusion level of CFP to completely replace the use of corn gluten meal (CGM) was shown to support shrimp growth in the pond that was historically heavily infected with pathogen, including white spot syndrome virus (WSSV) and acute hepatopancreatic necrosis disease (AHPND). In an indoor growth trial parallel with the pond challenge study, CFP at the level of 6, 12 and 18% at the expense of fish meal (FM), soybean meal (SBM) and CGM were also able to improve growth and several related parameters such as final body weight, percentage weight gain and thermal growth coefficient (TGC). The feed conversion ratios (FCR) for shrimp fed with CFP were also lower compared to the shrimp fed without CFP. Numerically, despite no statistical difference, survivability, and total haemocyte count were also elevated for shrimp receiving CFP. The challenge test results showed that the mean cumulative survival rate of shrimp injected with V. harveyi at the dose of 5 x104 CFU shrimp-1 were higher in the group of shrimp fed CFP compared to the control treatment. Values for mean phagocytosis activity were superior for fermented corn-fed shrimp. Meanwhile, haemocyte profiles remained uniform across treatments and phagocytic index was significantly reduced at 18% inclusion level of CFP. Phenoloxidase activity post-challenge with V. harveyi was elevated in shrimp fed CFP at all levels. These findings suggest that 6 – 12% inclusion of CFP can be utilized as a novel ingredient for shrimp feed. Advocating for functional ingredients with characteristics that can support health and welfare of intensively farmed shrimp will be of strategic importance in the future for sustainable production of shrimp under intensive conditions.
Key words Corn Fermented Protein, Improved Growth, Disease Resistance, Litopenaeus vannamei
... The authors hypothesized that the improved survival rate of challenged shrimp was probably due to an increase in the total haemocyte count (THC) and phagocytosis index which suppressed the population of Vibrio in the treatment group compared to the control. The single-cell protein of some yeast such as Saccharomyces cerevisiae and Candida species have also been wildly used as probiotics in aquaculture (Li and Gatlin 2003;Ayiku et al. 2020). The probiotics effects of S. cerevisiae include enhancement of host immunity, better growth performance, and protection against pathogenic infections (Yuan et al. 2019). ...
The shrimp industry has an urgent challenge of managing the outbreak of diseases majorly caused by bacteria and viruses. Vibriosis is one of the most common diseases encountered in hatchery and aquaculture shrimp farms. The vibriosis-affected shrimps exhibit symptoms including an empty gut, loss of appetite, and red to brown gills, leading to body malfunction and mortality. Better management practices in hatcheries and grow-out ponds are prerequisites to preventing and controlling Vibrio sp. infection. Chemicals and antibiotics have been applied to control and treat disease-causing pathogens. However, many of these chemicals are not approved for use in several countries for the fear of bioaccumulation in the body and environment of treated organisms as well as the establishment of chemical-resistant strains over time. Therefore, biological control alternatives that are effective, economical, and environmentally safe have been suggested and are reviewed herein. In this review, we advanced the potentials of probiotics and prebiotics, medicinal plants, biofloc, bacteriophages, and nanoparticle technology as bioactive measures in preventing and curing different vibriosis infections in addition to evaluating the limitations and future perspectives.
Graphical Abstract
... The addition of a suitable amount of yeast extract to poultry feed can strengthen the immunity of birds and reduce the incidence of disease [19,20]. Many countries have banned the use in pig feed of spray-dried animal plasma (SDPP), which is a safety risk that is also expensive as a protein supplement [21], so many pig farmers have switched to yeast extracts that are safer and relatively inexpensive. ...
Korean ginseng (Panax ginseng C. A. Meyer), a member of the Araliaceae family, is known as a traditional medicine plant to have a wide range of health properties. Polysaccharides constitute a major component of Korean ginseng, and its berries exhibit immune modulating properties. The purpose of this study was to investigate the immune effects of crude polysaccharide (GBPC) extracted from Korean ginseng berry on peritoneal macrophages in mice with cyclophosphamide (CY)- induced immunosuppression. BALB/c mice were divided into eight groups: normal control, normal control + CY, levamisole + CY, ginseng + CY, and four concentrations of 50, 100, 250, and 500 mg/kg BW/day of GBPC + CY. Mice were orally administered with samples for 10 days. Immunosuppression was established by treating mice with CY (80 mg/kg BW/day) through intraperitoneal injection on days 4 to 6. The immune function of peritoneal macrophages was then evaluated. Oral administration of 500 mg/kg BW/day GBPC resulted in proliferation, NO production, and phagocytosis at 100%, 88%, and 91%, respectively, close to the levels of the normal group (100%) of peritoneal macrophages. In CY-treated mice, GBPC of 50-500 mg/kg BW/day also dose-dependently stimulated the proliferation, NO production, and phagocytosis at 56-100%, 47-88%, and 53-91%, respectively, with expression levels of immune-associated genes, such as iNOS, COX-2, IL-1β, IL-6, and TNF-α, of about 0.32 to 2.87-fold, compared to those in the CY group. GBPC could be a potential immunomodulatory material to control peritoneal macrophages under an immunosuppressive condition.
... Besides immunostimulation, growth-promoting and antioxidant activity have also been documented in fishes fed with BSY. It has been reported that the minimal level (2-5%) of inclusion of BSY as a feed additive in aquafeeds resulted in increased growth responses of fishes (Chotikachinda et al., 2008;Li and Gatlin III, 2003;Matulić et al., 2020;Ran et al., 2016;Zhou et al., 2018). This may be because of the vast bioactive compounds in BSY biomass. ...
Aquaculture contributes significantly to the world’s food security. Future aquaculture developments depend mainly on sustainable aquafeed production. Fish meal (FM) is considered unsustainable and not eco-friendly but remains a major protein ingredient in aquafeeds production. The aquaculture sector seeks sustainable protein sources that can reduce the dependency on fishmeal in aquafeeds production. Brewer's spent yeast (BSY) is waste biomass obtained from beer breweries worldwide, and its disposal hazards the natural environment. BSY can be deactivated and used as a single cell protein source in aquafeeds as it has good nutritional value with high protein content (49%) and is cheaper than fishmeal. It also possesses antioxidant and immunostimulant properties. This review focuses on the utility of BSY biomass in aquafeed production. Broken line regression analysis from current literature suggests that the optimal range of BSY inclusion in feed is 10-31.5% for carnivores and 19-31.6% for omnivore fish; FM
replacement using BSY is 30-50% for carnivores and 35-80.8% for omnivore fish. Also, the utilization of BSY in the global aquafeed industry could reduce fishmeal usage by up to 13.94% (0.369 MMT) globally and reduce the carbon footprint by about 1.79 megatonnes of CO2e and fish-in-fish-out ratio (FIFO) from 0.82:1 to 0.71:1. Thus, utilization of BSY in the aquaculture sector improves circular bio-economy and environmental sustainability in fish production.
... Yeasts contain 45-55 per cent crude protein and can replace fishmeal up to 75 per cent in fish diets without compromising growth (Gamboa-Delgado et al. 2016;Pongpet et al. 2016). Yeasts can also be included in low concentrations as a catalyst in fish diets, improving the efficiency of using plant protein (Li and Gatlin III 2003). Inclusion of yeast increases feed efficiency (Gamboa-Delgado and Márquez-Reyes 2018; Pongpet et al. 2016) and enhances fish immunity against bacterial diseases (Iwashita et al. 2015). ...
Papers from the Rural development report 2021
... There are several examples of singlestrain probiotics. For example, Saccharomyces cerevisiae has been efficiently evaluated as a probiotic yeast with a well-known ability to boost immunity and enhance defensive mechanisms in a variety of finfish species (Abdel-Tawwab et al., 2008;Chiu et al., 2010;Li and Gatlin, 2003;Rodrı́guez et al. Rodriguez et al., 2003). ...
An eight-week trial was designed by feeding Pangasianodon hypophthalmus fingerlings on diets supplemented with a multispecies probiotic comprised of three probiotic bacteria (Bacillus subtilis, Lactobacillus plantarum, and Enterococcus faecium) in combination with a probiotic yeast (Saccharomyces cerevisiae). The dietary effects were observed regarding growth, body composition, digestive enzymes, liver function enzymes, serum metabolites, immunological responses, hepatic antioxidant capacity, and resistance to the challenge with Aeromonas hydrophila. Fish (9.54 ± 0.50 g) were allocated into four triplicate groups and were fed on formulated pelleted diets enriched with varying levels of the probiotic as 0.0 (reference or CONT), 0.5, 1.0, and 1.5 g per 1 kg feed for successive 56 days. After the feeding trial ended, a significant augmentation of the growth performance in terms of the fish's final weight, weight gain and specific growth rate were observed in the probiotic-enriched groups in comparison to the CONT group. There were also improvements in the feed intake and feed conversion ratio. Nevertheless, no variations were noticed in whole-body analysis, liver enzymes (AST, ALT, and ALP), and serum metabolites (blood urea nitrogen, uric acid, and creatinine) among the experimental groups. Meanwhile, digestive enzymes (lipase, amylase, and protease) and enzymatic antioxidant activities (CAT, SOD, and GPx) were increased in all probiotic-supplied groups in comparison with the CONT group. On the other side, hepatic malondialdehyde concentrations declined in probiotic-supplemented groups in relation to the CONT group. An improved immunological response (serum lysozyme activity and total immunoglobulins) was aligned with the higher cumulative survival of P. hypophthalmus in response to the pathogenic A. hydrophila challenge. Taken together, the enhancement of the growth, antioxidant activity, and immunity, aligned with increased resistance to A. hydrophila, can suggest the potentiality of dietary supplementation of a multispecies probiotic composed of probiotic bacteria and yeast to improve the functionality and effectuality of aquadiets prepared for this valuable fish species.
... Yeast, S. cerevisiae, contains various immunostimulating compounds indicating the potentiality of use of whole yeast as natural immunostimulants in common fish diets such as seabream Sparus aurata [36]. In addition, the yeast can be used in culture of hybrid striped bass (Morone chrysops × Morone saxatilis) [37]. Some studies have been done on feeding yeast protein on the growth and feed utilization parameters of Clarias gariepinus, O. niloticus, Atlantic salmon, rainbow trout, and whiteleg shrimp which are cultured separately [16,18,19]. ...
With the technological advancement, application of yeasts in aquaculture becomes very popular, especially as an alternative source of proteins in addition to other proteins commonly used in the fish feed industry. Recently, yeast becomes a sustainable novel ingredient of aquafeed for its promising role in nutrition and immunostimulation of many fish species in aquaculture. Thus, yeast supplements and yeast-containing feed ingredients lead to the higher protection against diseases and to the better productivity of fishes resulting in the greater growth of the aquaculture industry. Moreover, rotifers, Artemia, and copepods can be produced well as live aquafeed by application of yeasts in aquaculture. Some yeasts used in probiotic products often improve immunity of fishes as well as attempt to enhance the water quality of aquaculture resulting in good production outcomes. Thus, yeast has been appeared as a novel and vital component of aquatic animal’s feed in modern aquaculture. In this review, different aspects of usage of yeasts in aquaculture nutrition and immunostimulation have been discussed.
... There is also a strong body of evidence suggesting the suitability of whole-cell yeast as a partial replacement for fishmeal protein in the diets of numerous commercially cultured finfish species. Increased growth performance has been observed when commercial yeast cultures are supplemented in the diets of Hybrid striped bass (Morone chrysops x M. saxatilis; Li & Gatlin, 2003, Li & Gatlin, 2004and Li & Gatlin, 2005, Sea bream (Dicentrarchus labrax; Oliva-Teles, Guedes, Vachot, & Kaushik, 2006), trout (Barnes, Durben, Reeves, & Sanders, 2006;Hauptman et al., 2014;Martin, Goddard, & Bemibster, 1993;Rumsey, Hughes, & Kinsella, 1990;Vidakovic et al., 2020), Atlantic salmon (Salmo salar; Sahlmann et al., 2019) and tilapia (Abass, Obirikorang, Campion, Edziyie, & Skov, 2018;Abdel-Tawwab, Mousa, & Mohammed, 2010;Chen et al., 2019). The growth, feed conversion, and nutrient retention efficiency data from our second study align with the results of these studies and indicate a potential benefit to extended dietary yeast supplementation using a product derived from P. guilliermondii on rainbow trout production efficiency. ...
This study examined supplementation of a novel yeast product containing Pichia guilliermondii on juvenile rainbow trout, Oncorhynchus mykiss, growth, and disease resistance. In two separate trials, fish (initial weight 6.2 and 10.6 g, respectively), were fed an extruded diet (41% digestible protein and 18% crude lipid) supplemented with 0.3 or 0.6% P. guilliermondii alone or 0.3% P. guilliermondii with a dietary gut supplement at 0.1%. Prior to the end of each trial, a subsample of fish from each tank was exposed by immersion to Yersinia ruckeri (Trial 1) or injection with Flavobacterium pyschrophilum (Trial 2). At the conclusion of the trials, supplementation of either P. guilliermondii or the gut supplement improved growth and food conversion efficiency in rainbow trout when fed for 16-weeks. No effects of supplementation on mortality were observed. These results suggest potential as functional additives; however, additional investigation regarding the efficacy of whole-cell and disrupted wall components of P. guilliermondii is needed to better assess their potential effects on rainbow trout immune responses.
... Yeasts contain 45-55% crude protein and can replace fishmeal up to 75% in fish diets without compromising growth (Gamboa-Delgado et al., 2016;Pongpet et al., 2016). Yeasts can also be included in low concentrations as a catalyst in fish diets, improving the utilization efficiency of plant protein (Li & Gatlin III, 2003). Inclusion of yeast increased feed efficiency (Gamboa-Delgado & Márquez-Reyes, 2018;Pongpet et al., 2016) and enhanced fish immunity against bacterial diseases (Iwashita et al., 2015). ...
In the discourse about the development of farmed animal production (terrestrial livestock production and aquaculture) in the tropics, two important food system outcomes emerge: (1) to supply animal-sourced food (ASF) at a level that suffices healthy future diets, including for poor people, and (2) to contribute to climate change mitigation and minimize pollution with nitrogen and phosphorus. Livestock production and aquaculture contribute to food security directly by increasing producers’ food diversity and availability, but also that of urban consumers, and indirectly through income generation and increased farm resilience. Recently, circularity has come to the fore as an integrated approach to food system development. Circularity has four cornerstones: (1) food crops have highest priority (which implies no food-feed competition), (2) avoid losses, (3) recycle waste and (4) use animals to unlock biomass that humans cannot eat. In this review, the role of farmed animals in circular food systems in the tropics is presented in four case studies and the impacts of circularity on food security and environmental impact mitigation are discussed. The cases are ruminants in grazing systems in West Africa and in Colombia, fish in pond aquaculture in general, and land-limited dairy production in Indonesia. Additionally, options for novel protein sources for use in livestock and fish feeding are presented. It is concluded that farmed animals are important in circular food systems because of their use of land unsuited for crop production, their upgrading of crop residues, and their supply of manure to crop production. Nevertheless, the increasing demand for ASF puts pressure on important characteristics of circularity, such as minimizing food-feed competition, maximization of use of waste streams in feed, and the value of manure for fertilization. Hence, in line with conclusions for Western countries, maximum circularity and sustainability of food systems can only be achieved by optimizing the population size of animals. Thus, a sustainable contribution of ASF production to global food security is complex and in not only a technical matter or outcome of an economic process balancing supply and demand. It requires governance for which public, private, and social actors need to partner.
... Further, the graded levels of brewer yeast supplement in diet of hybrid striped bass (Morone chrysops×M. saxatilis) significantly improves growth (Li and Gatlin, 2003), similar to our findings (Table 9). Also the result of significant improvement in digestive enzyme activity (amylase, lipase and pepsin) with increasing levels of dietary yeast supplements (Table 9) in our study confirms the prospective impacts of yeast supplement on growth and feed utilization (Banu et al., 2020). ...
A 50 days feeding trail was conducted to evaluate the efficiency of spent oleaginous yeast Lipomyces starkeyi by-product from wheat straw as a probiotic supplement on juvenile red sea bream (Pagrus major). Elements that were investigated includes physiological condition, digestive enzyme, haemato-biochemistry, antioxidant, immune and stress. 300 juvenile P. major (9.13±0.05 g) were randomly distributed into 200 L polyethylene tank (20 fish per tank) in triplicate of 5 treatments; CD1 control (0 g/kg supplement), D2 (1%, 10 g/kg supplement), D3 (1.5%, 15 g/kg supplement), D4 (2%, 20 g/kg supplement), D5 (2.5%, 25 g/kg supplement). The fish were fed twice daily and sampling for weight and length were conducted at 35 and 50 days of the feeding trial. Whole body samples, digestive organs and blood collection was done at the end of the feeding trial. The results of the combine parameters assessed by multivariate analysis revealed that fish group fed on D5 has significantly better performance followed by D4, D2 and D3 compared to the fish group fed the control diet D1 (ANOSIM, P
... Nile tilapia Immunity (Iwashita et al., 2015) Yeast Biomass Nile tilapia Survival rate and blood profiles (Sutthi et al., 2018) Yeast Biomass Striped bass Immunity (Li & Gatlin, 2003) Yeast Biomass ...
Aquaculture is considered one of the world's fastest-growing
food production industries. It provides one of the most environmentally friendly sources of edible protein. The rapid expansion of aquaculture has occurred in response to a huge increase in world population and the corresponding demand for food, highlighting a path towards
intensive sustainable products and resource efficiency. Improved process efficiency
has fuelled aquaculture expansion, which involves addressing operational performance,
particularly on nutrition and health of farmed fish, as well as a trend towards
reaching natural or organic certification. Although there is ample evidence to support
the use of microorganisms, including algae, bacteria, fungi, archaea, protozoa and viruses,
their use in aquaculture nutrition is still limited in natural medicine development
and therapies. Notably, various applications of microorganisms feed have a significant
impact on aquatic animal health and husbandry. However, there is a need to discuss
various roles of microorganisms used in aquaculture feed extensively. This review
discusses the potential of microorganisms and their role as value added aquaculture
feed, which could offer aquaculture and feed producers considerable benefits.
... Secondly, a competitive rejection of pathogenic bacteria by yeast and its produces mainly the cell wall component (Onifade 1998). Cell wall of yeast is containing chitin, glucan and mannan which have been identified as immunostimulante (Li and Gatlin 2003). This study aimed to explore the effects of Saccharomyces cerevisiae supplement on the growth performance, carcass traits and economic efficiency of growing rabbits. ...
... The supernatant was collected, and its optical density was measured at 540 nm. Absorbance was converted to mg NBT diformazan/ml blood according to Li and Gatlin [38]. ...
The effects of dietary β-glucan on innate immune responses have been shown in a number of different vertebrate species. However, there is conflicting information about the period of administration (shorter vs. longer), and it is also unclear to what extent β-glucan’s effects can be observed post-treatment in fish. Thus, we fed Nile tilapia for 0 (control group; 45 days of control diet), 15 (30 days of control followed by 15 days of β-glucan), 30 (15 days of control followed by 30 days of β-glucan) or 45 days with a diet containing 0.1% of β-glucan (MacroGard®). We evaluated the growth performance at the end of the β-glucan feeding trial and the innate immune function immediately after the feeding trial and 7 and 14 days post-feeding trial. In addition, at day 10 post-feeding trial, we assessed the tilapia’s resistance against a bacterial infection. No significant differences were observed in growth performance between the groups; however, fish fed with β-glucan for 30 and 45 days had higher (approx. 8%) relative weight gain compared to the control. Regardless of the administration period, fish fed with β-glucan had higher innate immune responses immediately after the feeding trial such as lysozyme activity in plasma, liver and intestine and respiratory burst compared to the control, and in general these differences were gradually reduced over the withdrawal period (up to 14 days). No differences were observed in the plasma hemolytic activity of the complement or myeloperoxidase activity in plasma or intestine. Moreover, fish from the control group had early mortalities (2 vs. 4–5 days post-infection, respectively) and a lower survival rate (60 vs. 80%, respectively) compared to fish fed with β-glucan for 15 or 30 days, and, interestingly, fish fed for 45 days with β-glucan had no mortality. This study indicates that regardless of the administration period (i.e., 15 up to 45 days), the β-glucan improved the innate immune responses and the tilapia’s resistance to disease, and this protection could be observed up to 10 days post-feeding trial, adding in vivo evidence that β-glucan may contribute to a trained innate immunity. Additionally, we showed that a longer period of administration did not cause immunosuppression as previously hypothesized but promoted further growth and immune performance. These findings are relevant to the aquaculture industry and demonstrate that a longer β-glucan feeding protocol may be considered to achieve better results.
... The respiratory burst activity of fish phagocytes can be modulated in vivo and in vitro by many substances (Tahir and Secombes, 1996), glucans (Couso et al., 2001), levamisole (Mulero et al., 1998) and animal extracts (Bøgwald et al., 1996). Li and Gatlin (2003) found that feeding juvenile hybrid striped bass a diet supplemented with growth promotion for 16 weeks increased blood neutrophil oxidative radical production and extracellular superoxide anion production of head kidney leucocytes. ...
A total number of 135 Nile tilapia (O. niloticus) were used to study the effect of dietary supplementation with black cumin seed (Nigella sativa) on growth performance and some blood constituents. The fish were randomly divided into three treatment groups each of 45 fish, and each group was divided into 3 subgroups (15 fish / unit). These groups received N. sativa at 1% (T1) and 2% (T2) and control group (C) which fed on basal diet without N. sativa. Body weight and length were recorded biweekly all over the experimental period (12 weeks). Blood samples from each fish were collected to determine each of hemoglobin (Hb), packed cell volume (PCV%), serum glucose, total protein, albumin, globulin, and alkaline phosphatase. Ten fish were scarified to determine hepatosmatic index (HSI), spleen somatic index (SSI), and gonadosomatic index (GSI). Other ten fish were transported to wet laboratory and reared without oxygen supplementation to determine the resistance under oxygen deficiency. The results showed that there was insignificant increase in body weight, body weight gain, total length, and length increment in T2. Also, the hemoglobin increased insignificantly (P > 0.05) in T2 than the control. Moreover, the serum albumin improved insignificantly (P > 0.05) in T1 and T2 than the control. Serum alkaline phosphatase was significantly (P < 0.05) increased in treated fish with N. sativa; while serum glucose decreased significantly (P < 0.05) as compared with control ones. The hepatosoatic index (HSI) insignificantly (P > 0.05) decreased in T1 and increased insignificantly (P > 0.05) in T2 compared to the control. Also, the dietary 1 and 2 % N. sativa did not affect spleenosomatic index (SSI). The fish group which reared under oxygen deficiency exhibited remarkable decreased activity and increased random movement elicited by hypoxia changes in direction of swimming, while the fish groups fed diets with N. sativa showed slightly abnormal behavior changes. The mortality rates under oxygen deficiency were 100, 40 and 20% for control, T1 and T2, respectively. Under oxygen deficiency stress, the Hb and glucose did not differ between T1 and T2, while PCV% was increased significantly (P > 0.05) in T2 than that of T1; the same occurred (P < 0.05) with serum total protein concentration, globulin, and alkaline phosphatase activity, but serum albumin in T1 was higher than that of T2 (P < 0.05). There were no significant (P > 0.05) in HIS, SSI and GSI between treated groups with N. sativa and control ones. To conclude, the dietary supplementation with N. sativa at 1% and 2% displayed slight beneficial effects on growth performance and major effects on some blood constituents of O. niloticus.
... Feeding 58 g/kg of yeast extract and 230 g/kg of brewer's yeast resulted in increased growth and feed intake in gilthead sea bream (Sparus aurata) [184]. For hybrid striped bass (Morone chrysops × M. saxatilis), similar weight gain, feed efficiency and survival were found when fed up to 40 g/kg brewer's yeast, although fish had higher survival after a bath infection with Streptococcus iniae [185]. The tolerance of high inclusion levels of yeast SCP seems to depend on the marine species and more research is needed to determine acceptable feeding levels and benefits to growth performance and feed utilisation. ...
Single-cell ingredients (SCI) are a relatively broad class of materials that encompasses bacterial, fungal (yeast), microalgal-derived products or the combination of all three microbial groups into microbial bioflocs and aggregates. In this review we focus on those dried and processed single-cell organisms used as potential ingredients for aqua-feeds where the microorganisms are considered non-viable and are used primarily to provide protein, lipids or specific nutritional components. Among the SCI, there is a generalised dichotomy in terms of their use as either single-cell protein (SCP) resources or single-cell oil (SCO) resources, with SCO products being those oleaginous products containing 200 g/kg or more of lipids, whereas those products considered as SCP resources tend to contain more than 300 g/kg of protein (on a dry basis). Both SCP and SCO are now widely being used as protein/amino acid sources, omega-3 sources and sources of bioactive molecules in the diets of several species, with the current range of both these ingredient groups being considerable and growing. However, the different array of products becoming available in the market, how they are produced and processed has also resulted in different nutritional qualities in those products. In assessing this variation among the products and the application of the various types of SCI, we have taken the approach of evaluating their use against a set of standardised evaluation criteria based around key nutritional response parameters and how these criteria have been applied against salmonids, shrimp, tilapia and marine fish species.
... Yeast is often applied to aquaculture as live probiotics or feed ingredients (Jin et al., 2018). In regards to yeast or yeast extract, some studies have illustrated their beneficial impacts on growth, immune responses and stress resistance of aquatic animals (Biswas et al., 2012;Jin et al., 2018;Li and Gatlin, 2003;Signor et al., 2010). In our present study, the obtained immunologic active substance from hydrolyzed yeast (Rhodotorula mucilaginosa) are mainly natural existed mannan oligosaccharides (MOS) as well as β-glucan. ...
To explore the impacts of dietary hydrolyzed yeast (Rhodotorula mucilaginosa) and Bacillus licheniformis (B. licheniformis) on the growth, intestinal histology, innate immune response and ammonia resistance of Litopenaeus vannamei, four experimental diets (basal diet (Control); 0.5 % hydrolyzed yeast (HY); 0.1 % B. lincheniformis (BL) and 0.5 % hydrolyzed yeast + 0.1 % B. licheniformis (SYN)) were fed shrimps for 8 weeks. Results showed no significant differences on growth and body composition among all treatments, while a significantly higher feed efficiency (FE) in shrimp fed BL diet and a significantly higher protein efficiency ratio (PER) in shrimp fed BL and SYN diets were found compared to those in shrimp fed the Control diet (P
... Previous studies established that protein from S. cerevisiae yeast can successfully replace up to 50% of fishmeal protein without negative effects on fish growth performance, whereas a dietary inclusion of up to 30% of brewer's yeast improved feed efficiency [12][13][14]. However, poor nitrogen digestibility, probably due to the external mannoprotein cell wall, can represent an important constraint in the use of this type of SCP in aquafeed production [15,16]. ...
Background:
This study evaluated the effects of partial substitution of dietary fishmeal (FM) with either fish protein hydrolysate (FPH) or autolysed dried yeast (HiCell®, Biorigin, Brazil) on intestinal microbiota of gilthead sea bream (Sparus aurata). A total number of 720 fish of 122.18 ± 6.22 g were fed for 92 days with three different diets in triplicate (3 tanks/diet). A diet based on FM/vegetable meal was used as control. The other two diets were formulated by replacing FM with 5% of either FPH or HiCell®. To analyze the gut microbiota associated to autochthonous and allochthonous microbial communities, the Illumina MiSeq platform for sequencing of 16S rRNA gene and QIIME pipeline were used.
Results:
A total number of 102 OTUs (operational taxonomic units) at 97% identity were identified in fish gut samples collected at the end of feeding trial. Fourteen OTUs constituted the core gut microbiota, i.e. those OTUs found in at least nine out of fifteen samples per group and shared regardless of the diet. Eight OTUs were assigned to Firmicutes represented by Lactobacillus, Staphylococcus, and Bacillus genera, and six to Proteobacteria phylum. Dietary dried yeast autolysate modulated the intestinal microbiota by promoting the growth of some beneficial bacteria. At order level, fish fed yeast showed an enrichment in Bacillales and Clostridiales as compared to the control group, whereas fish fed FPH showed a significantly lower amount of bacteria belonging to Alteromonadales and Enterobacteriales than the other two feeding groups. Although we did not observe any effect of 5% FM replacement with alternative nitrogen sources at phylum level, at lower taxonomical levels, the composition of gut microbiota, in terms of relative abundance of specific taxa, was significantly influenced by the dietary treatment.
Conclusions:
The metabarcoding analysis revealed a clearly intestinal microbiota modulation in response to dietary autolyzed yeast. The abundance of some beneficial bacteria, i.e. indigestible carbohydrate degrading- and SCFA producing bacteria, was positively affected. Brewer's yeast autolysate could be a valid alternative protein source to FM as well as a valid functional ingredient for aquafeed production.
... This favourable nutrient profile drives its commercialization as a co-product, to be used as a feed supplement for various animals, including fish (Abdel-Tawwab 2012). The inclusion of this yeast at probiotic levels (up to 2%) improved performance and welfare in fish (Essa et al. 2011;Li and Gatlin 2003), without bringing negative effects on growth performance when fish were fed below 15% yeast (Ozório et al. 2012). ...
Saccharomyces cerevisiae biomass generated as a by-product in industrial processes and other biomasses grown in industry waste waters like Spirulina platensis and Rubrivivax gelatinous can be used in aquafeed, thus reducing the costs of discard and minimizing environmental damage. In this study, 840 male Nile tilapias (Oreochromis niloticus; 26.8 ± 1.03 g average weight) were distributed among 21 tanks (40 fish/tank, 1.07 kg/m3). Fish were fed to satiation three times a day throughout the trial (72 days). A completely randomized design experiment with 7 treatments (control group and 6 different diets, 3 replicates per treatment) was conducted to investigate the effects of these three microbial biomasses (added at 0.25 and 0.5% into an isoproteic/isoenergetic tilapia diet) on the growth and visceral indexes of the fish and on the composition and texture of the fillets. Feed conversion ratio was significantly lower in fish fed 0.5% R. gelatinosus than that in the control group, but no difference was detected among the treatments either for the other growth indicators or for the organs’ indexes. Including microbial biomass in the diet did not significantly affect either fillet pH or texture parameters. However, the use of microbial biomass increased the protein content and decreased the n-6/n-3 ratio of the fillets compared with that of the control group. So, it was concluded that the dietary intake of low concentrations of S. cerevisiae, S. platensis and R. gelatinosus biomasses did not affect the growth performance of tilapias, increased the nutritional quality and preserved the texture features of the fillets.
... Yeast cell wall contains chitin, mannan and glucan that have been known as immunostimulants (Attia et al., 2017;Al-Khalaifah, 2018;Jin et al., 1998;Li and Gatlin III, 2003;Rodrıguez et al., 2003). Yeast has been shown in many studies to increase production performance due to the improved intestinal length of the villi, which helps in effective digestion. ...
A total of 216 one-day-old Arbor Acres broiler chicks were randomly distributed among 36 cages of 6 replicates per treatment and 6 birds per cage during 1–38 d of age. A factorial design (2 × 3) was used in which there were two feed rations [standard diet vs. marginal nutrients deficiency-diet (MNDD)] and three Saccharomyces cerevisiae (SC, active yeast) concentrations (0, 0.02 and 0.04%). The results showed that marginal nutrients deficiency-diet significantly decreased growth rate and production index during the experimental period and this accounted for 5.4% for the whole period. The MNDD impaired feed conversion ratio (FCR) during 1–21 d of age, but FCR for the whole period was not affected. Addition of SC at 0.04% significantly improved growth rate and increased organic matter digestibility and apparent ash retention, compared to 0.02% diet. Addition of SC had a significant effect on percentage of gastrointestinal tract and length of villi. Dressing percentage was significantly higher for the group fed on MNDD than those on the standard diet. The increase in the dressing percentage was associated with significantly higher gizzard, gut percentage and length of the intestine. The type of diet, the SC concentration, and the interaction between them had no significant effects on the chemical composition and the physical characteristics of the meat. It could be concluded that SC supplementation to standard- or MNDD improved growth performance of broiler chickens. Hence, feeding MNDD supplemented with either 0.02 or 0.04% SC showed higher growth performance than the standard diet without SC supplementation.
... trout (Oncorhynchus mykiss, Huyben et al., 2017;Jin et al., 2018), turbot (Scophthalmus maximus, Librán-Pérez, Costa, Figueras, & Novoa, 2018, gilthead sea bream (Sparus aurata, Gultepe, Salnur, Hossu, & Hisar, 2011;Dawood et al., 2017), Nile tilapia (Hassaan et al., 2018;Ozório, Portz, Borghesi, & Cyrino, 2012;Pilarski, Ferreira de Oliveira, Darpossolo de Souza, & Zanuzzo, 2017;Sado, Bicudo, & Cyrino, 2008), largemouth bass (Micropterus salmoides, Zhou et al., 2018), Pacific white shrimp (Litopanaeus vannamei, Zhang et al., 2012;Qiu & Davis, 2017;Jin et al., 2018), Jian carp (Cyprinus carpio var. Jian, Yuan et al., 2017), gibel carp (Carassius gibelio, Zhang et al., 2018), common carp (Cyprinus carpio, Momeni-Moghaddam, Keyvanshokooh, Ziaei-Nejad, Parviz Salati, & Pasha-Zanoosi, 2015), hybrid striped bass (Morone chrysops x Morone saxatilis, Li & Gatlin, 2003), giant freshwater prawn (Macrobrachium rosenbergii, Prasad, Nayak, Srivastava, Reddy, & Kohli, 2013), Thai panga (Pangasianodon hypophthalmus × Pangasius bocourti, Pongpet, Ponchunchoovong, & Payooha, 2016), channel catfish (Ictalurus punctatus, Peterson, Booth, Barrows, & Manning, 2012), European seabass (Dicentrarchus labrax, Torrecillas et al., 2007, Torrecillas et al., 2011, Torrecillas et al., 2015Salem, Gaber, Zaki, & Nour, 2016) and pacu (Piaractus mesopotamicus, Sado, Bicudo, & Cyrino, 2014). However, there is limited knowledge on the effects of brewer's yeast and its derivatives on farmed ...
A feeding trial was conducted to evaluate the potential of dietary supplementation of autolysed brewer's yeast (AY) on African catfish. The catfish (22.5 ± 1.15 g/fish, 20 fish 33 L/tank) were fed with either of diets (390 g/kg crude protein, 140 g/kg lipid) supplemented with 0, 3, 6 or 10 g/kg AY (n = 3). After 49 days of feeding, the final body weight and metabolic growth rate of the catfish fed 3 g/kg AY (3‐AY) diet were higher than those fed the control diet (p < .05). The lowest level (p < .05) of alanine transaminase was detected in the blood of the catfish fed 3‐AY diet. The mid‐intestinal histology of the catfish revealed no significant difference (p > .05) in intestinal perimeter ratio. However, an elevated (p < .05) abundance of goblet cells and intraepithelial leucocytes were found in the intestine of catfish fed 3, 6 and 10 g/kg AY diets, with the highest level of abundance recorded in the mid‐intestine of the catfish fed 3‐AY diet. The results suggest that dietary 3 g/kg autolysed brewer's yeast supplementation improves growth performance of African catfish without deleterious effect on liver functionality and gut morphology.
... Mucosal tissues are important for disease prevention and cure. There are several reports that suggest that probiotics have positive effects in the prevention of pathogen infection and improvement of the mucosal immune response [13][14][15]. Lactobacillus are "generally regarded as safe (GRAS)" microorganisms, and are used for antigen expression owing to their ability to present compounds on the mucous membrane and colonize in the gut [16]. Bacterial flagella are complex nano-machines motility that allows them to move towards nutrients and more favorable environments. ...
Aeromonas veronii is a pathogen capable of infecting humans, livestock and aquatic animals, resulting in serious economic losses. In this study, two recombinant Lactobacillus casei expressing flagellin A (FlaA) of A. veronii, Lc-pPG-1-FlaA (surface-displayed) and Lc-pPG-2-FlaA (secretory) were constructed. The immune responses in fish administered with recombinant L. casei were evaluated. The two recombinant L. casei were orally administered to common carp, which stimulated high serum IgM and induced higher ACP, AKP, SOD and LYZ activity. Using qRT-PCR, the expression of IL-10, IL-8, IL-1β, TNF-α and IFN-γ in the tissue of fish immunized with recombinant L. casei was significantly (p < 0.05) upregulated, which indicated that recombinant L. casei could activate the innate immune system to trigger the cell immune response and inflammatory response. Furthermore, recombinant L. casei was able to survive the intestinal environment and colonize in intestine mucosal. The study showed that after being challenged by A. veronii, fish administered with Lc-pPG-1-FlaA (70%) and Lc-pPG-2-FlaA (50%) had higher survival rates compared to Lc-pPG and PBS, indicating that recombinant L. casei might prevent A. veronii infection by activating the immune system to trigger immune responses. We demonstrated that flagellin as an antigen of vaccine, is acceptable for preventing A. veronii infection in fish. The recombinant L. casei expressing FlaA may be a novel mucosal vaccine for treating and controlling A. veronii.
A nucleotide-rich yeast-derived product (Maxi-GenTM; CBS Bio Platforms, Inc.; Calgary AB, Canada), was fed to rainbow trout fry housed at 10oC or 16oC to determine its effect on weight gain and feed intake. Rainbow trout fry housed in 40 16-L tanks (25 fish / tank) were fed commercial-type or synthetic diets with or without the nucleotide-rich yeast product added (0 or 0.5% inclusion) until they reached 60 days of age (5 tanks / 4 diets / 2 temperatures). Fish housed at 16oC consumed significantly more feed and gained significantly more weight than fish housed at 10oC. Trout fed the commercial-type diet gained significantly more weight than those fed the synthetic diet without the nucleotide-rich yeast product added. There was no significant difference in weight gain or feed intake among fish fed either commercial-type diet and the fish fed the synthetic diets with the nucleotide-rich yeast product added, although fish fed the commercial-type diets had significantly better feed conversion efficiencies than those fed the synthetic diets. The nucleotide-rich yeast product could be used in low fish meal, low fish oil first feeding diets, as the aquaculture industry decreases fish meal and oil use in aquafeeds in response to their increasing cost and decreasing availability.
a iFFO-the Marine ingredients Organisation, london, uK; b institute of Aquaculture, university of stirling, stirling, uK; c iFFO-the Marine ingredients Organisation, Beijing, china; d texas Agriculture & Medicine university, college station, texas, usA; e universidad de las Palmas de Gran canaria, spain; f norwegian university of life sciences, Aas, norway; g ciiMAR and icBAs, university of Porto, Porto, Portugal ABSTRACT A variety of new feed ingredients are emerging in the aquaculture feed sector. While the technology readiness of these options varies across and within the new ingredient classes, it remains important to consider them in terms of the overall feed ingredient spectrum. In this review, the use of marine, grain, terrestrial animal by-product and a range of novel (e.g., bacterial and yeast) resources being considered as potential protein feedstuffs for use in aquafeeds is explored. In comparing the nutritional attributes of each of the ingredient classes, an assessment framework is applied based on understanding the critical knowledge required to be able to accommodate any ingredient in a formulation process. To further examine each of the different ingredient classes a Strength-Weakness-Opportunity-and-Threats (SWOT) analysis is applied, to enable some consideration of what future potential may exist across the spectrum and what risks and opportunities they may bring. It is noted that all ingredients have strengths and weaknesses, and that there is no such thing as the perfect ingredient. By better appreciating the positives and negatives of each ingredient, it becomes possible to increase adaptability in responding to the various opportunities for their use in feeds.
In this study, 2 yeasts, Candida zeylanoides isolate Y12‐3 (MN073455.1) and Hyphopichia pseudoburtonii isolate Y12‐1 (MN073489.1), were isolated from rainbow trout hindguts. Their identity was confirmed by amplification of internal transcribed spacer (ITS) gene regions. Their in vitro probiotic properties showed that they were hydrophobic and did not inhibit bacterial growth. However, they displayed positive co‐aggregation with several bacterial pathogens. It was interesting that Y12‐1 and Y12‐3 isolates survived and grew well in bile salt concentrations ranging from 0.6% to 1.5% and at low pH conditions. After a 35‐day feeding trial, the results of dietary incorporation of the yeast isolates showed that serum myeloperoxidase activity was unchanged in the treated and control groups. Meanwhile, serum lysozyme activity in yeast groups was decreased significantly compared to the control. However, fish fed with Y12‐1 had higher total protein, albumin, and globulin than other groups. Total cholesterol levels were decreased significantly in yeast groups compared to the control. Interestingly, the Y12‐1 and Y12‐3 groups showed higher survival (69.05% and 80.95%) after the challenge with Lactococcus garvieae compared to the control (45.24%). In brief, the aforementioned findings showed that Y12‐1 and Y12‐3 strains could be potential probiotic candidates for use in rainbow trout farming.
Aquatic animals are continually being exposed to stressors under farming conditions, increasing risks to gut health that result in dysbiosis. Since restrictions are imposed on the frequent use of antibiotics in aquaculture, there is emerging demand for economically viable, environmentally safe, and sustainable alternatives for the intensive production of aquaculture species. The application of beneficial microorganisms as probiotics has been suggested and widely practiced in recent times. Bacteria and fungi are ubiquitous microorganisms that can grow in various environments where organic substrates are available. Being rich in nutrients, a fish’s aquatic environment and gastrointestinal tract confer a favorable culture milieu for the microorganisms. However, the colonization and probiotic potential of fungi and mycelial bacteria resembling fungi (actinobacteria), either in the culture environment or within the gastrointestinal tracts of fish, have received less emphasis. Apart from bacilli and lactic acid bacteria, as the most conventionally used probiotics in aquaculture, numerous studies have focused on other promising alternatives. Diverse species of yeasts and molds belonging to the kingdom ‘Fungi’ have been characterized for their prospective roles in nutrition, immunomodulation, and disease prevention in fish. Bioactive compounds such as manno-oligosaccharides and β-glucans are recognized as fungal postbiotics that improve innate immunity and disease resistance in fish. Actinobacteria are known to possess different hydrolytic enzymes and novel secondary metabolites representing their probiotic attributes. The application of these groups in water quality amelioration has also been explored. Thus, this paper presents an overview of the present status of knowledge pertaining to the effects of yeasts (Candida, Cryptococcus, Debaryomyces, Geotrichum, Leucosporidium, Pichia, Rhodosporidium, Rhodotorula, Saccharomyces, Sporidiobolus, Sporobolomyces, Trichosporon and Yarrowialipolytica), molds (Aspergillus spp.) and actinobacteria (Streptomyces) as probiotics in finfish aquaculture, as well as their occurrence within the gastrointestinal tracts of finfish. Furthermore, probiotic mechanisms, selection criteria, and future perspectives on using fungi and actinobacteria as promising probiotics are discussed.
Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.
A 60-day feeding trial was conducted to assess the effects of dietary Saccharomyces cerevisiae-originated free nucleotides on growth, innate immunity, intestinal histomorphometry and disease resistance in Nile tilapia, Oreochromis niloticus (average initial weight of 7.85 g). Five diets (treatments) were prepared: negative control diet (NCD) - basal diet without additives; positive control diet (PCD) - basal diet supplemented with a commercial nucleotide-based additive at 170 ppm; and three experimental diets, N170, N320 and N470, supplemented with S. cerevisiae-originated free nucleotides at 170, 320 and 470 ppm, respectively. There were no significant differences in production parameters after the trial period. Nevertheless, the complement hemolytic activity was higher in fish subjected to the three experimental diets, while serum lysozyme concentration was higher in the N470 group compared with both controls. Intestinal villi height and density were greater in fish fed the N470 diet compared with the NCD group. In addition, fish receiving the three experimental diets showed higher absorption surface area magnification ratio, with the greatest values being observed in the N470 group. Lastly, the highest survival rate following Aeromonas hydrophila challenge was recorded in the N470 group. Taken together, the present findings indicate that supplementation of feed with S. cerevisiae-originated free nucleotides at 470 ppm improves non-specific immune responses and intestinal microstructure morphology as well as increases survival rate after bacterial infection in Nile tilapia. Therefore, this blend of natural nucleotides has the potential of being used as an alternative to antimicrobials when included as an additive in aquaculture feeds.
The use of antibiotics in aquatic feed reduces the incidence of disease and enhances growth performance, although it presents harmful effects, such as development of resistant bacteria and accumulation in the natural environment. A variety of immune stimulants including probiotics, prebiotics, synbiotics, phytobiotics, organic acids, nucleotides, antioxidants, microalgae, yeast and enzymes have been used in the aquaculture industry. In recent decades, much attention has been paid on finding a variety of immunostimulants with lower cost which also affect specific and non-specific immunity and improve fish resistance against a wide range of pathogens. These stimulants strengthen the fish’s immune system by increasing the number of phagocytes, lysozyme activity and level of immunoglobulin. The use of immune stimulants as an effective tool to overcome diseases and strengthen the immune system of farmed species, leads to the promotion of cellular and humoral defense mechanisms and increases resistance to infectious diseases. Among these immunostimulants used in aquaculture, β-glucans are of particular importance. Glucans are complex polysaccharide compounds extracted from the cell wall of yeasts and fungi. These compounds can stimulate fish growth, survival, and immune function. Therefore, this review discusses the role and importance of β-glucan as a food additive in aquaculture and examines the impact of these compounds on the growth performance, immunity and biochemical parameters of farmed species.
This study investigated the effects of dietary supplementation of ESTAQUA® yeast culture (YC) on the growth, immunity, intestinal microbiota, and disease-resistance against Vibrio harveyi in hybrid grouper (♀Epinephelus fuscoguttatus×♂E. lanceolatus) at 0% (C0), 2% (N1), and 4% (N2). After 8 weeks of the feeding trial, the results indicated that the survival rate (SR), weight gain rate (WGR), and specific growth rate (SGR) of hybrid grouper were significantly higher in the N1 (2%) and N2 (4%) group than those in the control group (P < 0.05). Serum superoxide dismutase (SOD), catalase (CAT), total protein (TP), alkaline phosphatase (AKP), acid phosphatase (ACP), and immunoglobulin (IgM) activities were significantly higher in the N2 (4%) group (P < 0.05). Contrary to the control, aspartate aminotransferase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA), and glucose (GLU) were notably decreased in the N2 (4%) group (P < 0.05). The activity of intestinal digestive enzymes was significantly higher in the experimental groups than that in the control group (P < 0.05). Furthermore, at the phylum level, the relative abundance of Actinobacteria and Bacteroidetes was remarkably higher in the N2 (4%) group than that in the control group (P < 0.05). The relative abundance of Blautia and Lactobacillus was notably higher in the N2 (4%) group at the genus level (P < 0.05). Hybrid grouper in the N1 (2%) and N2 (4%) groups effectively improved intestinal villus height and width (P < 0.05). Lastly, the protection against V. harveyi challenge in hybrid grouper was enhanced in the YC treatment group, while N2 (4%) experienced the highest cumulative SR of 80%. In conclusion, the N2 (4%) treatment group is suggested as the best to improve the growth and immunity of hybrid grouper.
Probiotics, an eco-friendly alternative to antibiotics application appears to have strong potential for improving the sustainability of aquaculture. The aim of the study was to evaluate the effect of probiotic brewer's yeast, Saccharomyces cerevisiae supplementation on growth performance, feed utilization and intestinal morphometry of Nile tilapia, Oreochromis niloticus. A feeding trial of 60 days was conducted in which tilapia fingerlings (7.55 ± 1.25 g) were randomly distributed into three replicate aquaria under four different treatment groups, receiving S. cerevisiae at 0, 1, 2 and 4 g kg − 1 diet, respectively. At the end of the feeding trial, growth performance parameters (weight gain, WG; % WG; specific growth rate, SGR), feed utilization indices (protein efficiency ratio, PER; feed conversion ratio, FCR) and intestinal morphology were assessed. The results obtained from this study revealed that growth performance and feed utilization indices were increased significantly in the fish fed with 4 g kg − 1 S. cerevisiae supplemented diet compared to controls. The length, width and area of villus were significantly enlarged in fish fed 4 g kg − 1 S. cerevisiae supplemented diet. Likewise, intestinal mucosal fold, width of lamina propria, width of enterocytes and number of goblet cells increased in the fish fed with 4 g kg − 1 S. cerevisiae supplemented diet. These results demonstrated that S. cerevisiae can be effectively recommended as an important growth promoter for tilapia culture.
Application of probiotics in aquaculture helps to improve the survivability, growth and immunity of aquatic organism in sustainable aquaculture practices. This study was conducted to evaluate the probiotic potentiality of Streptomyces antibioticus EW1 and Bacillus cereus EW5 isolated from the digestive tract of earthworm (Eisenia fetida) and also determine their effects as probiotic in juvenile catfish (Heteropneustes fossilis). The bio safety assay confirmed that the isolates were not pathogenic to the host fish. These strains were able to survive in acidic as well as alkaline conditions, higher tolerance to bile salt as well as gastric juice and high surface hydrophobicity to solvents and displayed extracellular enzyme activity and moreover susceptibility to various antibiotics. Their antimicrobial activity was assessed against two fish pathogens: Aeromonas veronii (MN602971) and Stenotrophomonas maltophilia (MN602972). Among two isolates, the EW1 confirmed good antimicrobial activity against fish pathogens. The isolated bacterial strains were identified and established on the basis of their colony morphology, biochemical characteristics and 16S rRNA sequencing which revealed that the isolates exhibited 99 % sequence homology with Streptomyces antibioticus EW1 (MH301104) and Bacillus cereus EW5 (MH301102). A 45-day feeding trial was conducted to examine the effect of probiotic inoculated fish diet for the freshwater catfish Heteropneustes fossilis. Among three isonitrogenous (30 % CP) diets: RD (reference diet), T1 (diet with Streptomyces antibioticus) and T2 (diet with Bacillus cereus), fish fed T1 diet showed significantly higher growth, digestibility and higher values of crude protein and lipid than fishes reared with T2 and RD. The result of present study suggest that diet supplemented with Streptomyces antibioticus (T1) can be perform as safe probiotic and alternative protein source in the formulation of diet for H. fossilis.
Sustainable in-house cultures of bio-enriched live feeds for ornamental fish can enhance development, nutrition and welfare of the animal by improving immunity while further reducing economical costs to zoological institutions. Artemia is an easily harvestable feed with its nutritional profile highly dependent on its diet which is easily manipulated through bioencapsulation. This study evaluates the effects of two types of commonly used feeds for Artemia: spirulina and yeast, and how this affects the growth, feed conversion ratio (FCR), survival rate, immunity and colour intensity of ornamental fish, compared to a commercial pellet (control) diet. A total of 198 mature, mixed sex serpae tetra Hyphessobrycon eques were subjected to the three different diet treatments conducted in duplicate. There was no significant difference in growth weight, FCR, lysozyme, myeloperoxidase and alkaline phosphatase between treatments. Protease index of activity was significantly lower in fish fed with Artemia bio-enriched with spirulina (71.48%) and highest in the control diet (95.48%). The colour intensity and redness of the fish also significantly increased when fed Artemia bio-enriched with spirulina versus Artemia bio-enriched with yeast or a control diet.
Utilizing microbial products could be considered a novel approach to sustain the present growth of the aquafeed sector due to dwindling availability and high cost of fishmeal. Various microbial products in terms of isolates, whole-cell biomass, and live organisms are mainly derived from algae, bacteria, fungi, and yeast through the process of fermentation. They have a balanced amino acid profile and contain several minerals and vitamins. However, essential amino acid index (EAAI) of fungal-based microbial meal was comparatively lower (0.57–0.67) than the other three microbes (0.77–0.90). Microbes were deployed in the production of microbial products ranked as algae > fungus/yeast > bacteria based on their nucleic acid content. The global production of microbial products was valued at US$5.3 billion in 2017 and is predicted to increase by 8.6% in 2018–2023. They could substitute fishmeal by 25–50% in feeds for aquatic species. Notwithstanding, they act as a potential growth promoter, a viable immunostimulant and can control infectious diseases in various aquatic species. The present review reiterates the utilization of microbial products in ameliorating the issues related to the global aquafeed industry, in particular fishmeal demand. However, newer approaches need to be established with regard to fermentation technology and genetic engineering to overcome the present limitations to make them an economical one.
Utilizing microbial products could be considered a novel approach to sustain the present growth of the aquafeed sector due to dwindling availability and high cost of fishmeal. Various microbial products in terms of isolates, whole-cell biomass, and live organisms are mainly derived from algae, bacteria, fungi, and yeast through the process of fermentation. They have a balanced amino acid profile and contain several minerals and vitamins. However, essential amino acid index (EAAI) of fungal-based microbial meal was comparatively lower (0.57–0.67) than the other three microbes (0.77–0.90). Microbes were deployed in the production of microbial products ranked as algae > fungus/yeast > bacteria based on their nucleic acid content. The global production of microbial products was valued at US$5.3 billion in 2017 and is predicted to increase by 8.6% in 2018–2023. They could substitute fishmeal by 25–50% in feeds for aquatic species. Notwithstanding, they act as a potential growth promoter, a viable immunostimulant and can control infectious diseases in various aquatic species. The present review reiterates the utilization of microbial products in ameliorating the issues related to the global aquafeed industry, in particular fishmeal demand. However, newer approaches need to be established with regard to fermentation technology and genetic engineering to overcome the present limitations to make them an economical one.
The microbiome, an important aspect of fish aquaculture, is influenced by exogenous factors in the rearing environment including the composition and nutrient quality of the diet. To reduce reliance on fishmeal, alternative protein sources including yeast (Saccharomyces cerevisiae), have been successfully used in many aquafeeds. To investigate the effect of supplemented lysed and dried yeast on the fish physiology, including the intestinal epithelial‐associated microbiome composition, rainbow trout (Oncorhynchus mykiss) were fed a standard commercial diet or one of four additional in‐house extruded experimental diets containing 0%, 20%, 40% or 60% yeast nutrient supplement as a menhaden fishmeal substitute for 16 weeks. The commercial diet, 0%, and 20% supplement‐fed fish had similar average weight gains that were significantly (p < 0.05) higher in comparison to groups with a higher percentage of yeast. To examine if the yeast‐supplemented diet had any impact on the intestinal epithelial‐associated microbiome, both phylum‐ and family‐level comparisons of the microbial communities across treatments were made. The dominant families were Mycoplasmataceae and Fusobacteriaceae with Mycoplasma spp. and Cetobacterium somerae being the dominant organisms, respectively. Results from bioinformatics analysis showed little community variation between experimental diets, suggesting that lysed and dried yeast will serve as a dietary supplement without causing large shifts in the intestinal microbiome community.
Sustainability concerns associated with protein sources and currently used fish-meal and plant-based meal have necessitated the quests for novel sustainable ingredients for use in aquafeeds. Yeasts have been proposed as sustainable ingredients particularly because of their potential to valorise non-food lignocellulosic biomass into valuable protein resources. Prior to now, extensive studies exist on the role of yeast cell wall components in modulating health responses of fish. However, research on its use as a major protein source in fish diets is still in its infancy. The current review collates, synthesises and discusses the prospects of five major yeast species as future protein ingredients with respect to their nutritional adequacy in fish. Nutritional quality of Saccharomyces cerevisiae, Cyberlindnera jadinii, Kluyveromyces marxianus, Blastobotrys adeninivorans and Wicker-hamomyces anomalus and their use as replacement for fishmeal and soy protein in the diets of Atlantic salmon and rainbow trout are discussed based on three protein quality indices: chemical score, essential amino acid index and ideal protein concept based on the first limiting amino acids, methionine. The crude protein contents of yeast (40-55%) are lower than that of fishmeal, but comparable with soya bean meal. Compared to fishmeal, the different yeast species have favourable amino acid profiles, except for methionine, lysine, arginine and phenylalanine which are the frequently limiting essential amino acids in Atlantic salmon and rainbow trout. This review also presents future area of research and emphasise the need for large-scale production of yeast at competitive price to constitute a feasible replacement for fishmeal and soy protein in aquaculture.
Six iso‑nitrogenous and isolipid experimental diets were fed to orange-spotted groupers, Epinephelus coioides, and their growth performance, intestinal morphology, immune function and resistance to Vibrio harveyi infection evaluated. Positive controls (FM) were fed fishmeal as the only protein source. Negative controls (Y0) were fed a lower proportion of fishmeal in combination with plant proteins. The other groups were fed the Y0 diet supplemented with Saccharomyces cerevisiae hydrolysate at proportions of 10 g kg⁻¹ (Y1), 20 g kg⁻¹ (Y2), 30 g kg⁻¹ (Y3) and 50 g kg⁻¹ (Y5). Some 540 juvenile E. coioides (initial weight: 10.00 ± 0.05 g) were randomly divided into six groups, each with three replicates and 30 groupers per replicate. The experiment lasted 56 days. Rates of weight gain, special growth, feed coefficient and survival were not significantly influenced by diet. In the foregut and midgut, the villus length in group Y3 and muscle thickness in group Y1 were significantly higher than those in group FM. The expression levels of TLR22, INF-γ, and TNF-α were significantly higher in group Y0 than in Y1, Y2, Y3 and Y5. After V. harveyi challenge, the survival rate was significantly lower in group Y0 than in FM, while dietary supplementation with S. cerevisiae hydrolysate at 10 g kg⁻¹ and 20 g kg⁻¹ (Y1 and Y2) improved survival compared with group Y0 to a level comparable to that of group FM. These results indicate that a low-fishmeal diet supplemented with complex plant proteins and S. cerevisiae hydrolysate provides similar growth performance to a diet with fishmeal as the only protein source. Supplementation with S. cerevisiae hydrolysate increased the villus length and muscle thickness in the foregut and midgut, reduced the expression of intestinal inflammatory factors, and significantly improved resistance to V. harveyi infection.
The current study was conducted to evaluate the effects of different levels of yeast culture (YC) supplementation at 0% (YC 0%), 1% (YC 1%), and 2% (YC 2%) on growth, feed conversion ratio, body composition, intestinal morphology, microflora, immune response, and resistance to Vibrio harveyi infection in Litopenaeus vannamei. After 8-weeks feeding trial, the results showed significant improvement (p < .05) in the final weight, weight gain rate, specific growth rate, survival rate and low feed conversion ratio in YC groups than the control. Serum total protein, superoxide dismutase, catalase, alkaline phosphatase, acid phosphatase, lysozyme, and phenol oxidase in shrimps fed diet YC (2%) were significantly higher (p < .05), whereas significantly decreased trend in serum cholesterol, triglyceride, aspartate aminotransferase, and alanine aminotransferase (p < .05) were observed in YC (2%) diet. Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes were the core phylum bacteria found in the shrimp intestines. At the genus level, opportunistic pathogenic bacteria, Vibrio was significantly decreased (p < .05) while beneficial bacteria Pseudoalteromonas was increased in YC (2%) group. Intestinal villus height and width in shrimps fed YC diets were significantly improved than the control diet (p < .05). YC groups challenged test significantly showed (p < .05) improved shrimps immune response against V. harveyi infections with YC (2%) recording the highest percentage survival rate (70%). The present study demonstrated that supplementing YC (2%) can improve growth, intestinal microbiota, intestinal morphology, and immune response against V. harveyi infections in L. vannamei.
Pemanfaatan Saccharomyces cerevisiae yang disuplementasikan dalam pakan buatan berbasis protein nabati mampu meningkatkan pertumbuhan beberapa jenis ikan budidaya. Penelitian ini bertujuan untuk mengevaluasi pengaruh suplementasi S. cerevisiae dalam pakan pembesaran ikan baronang. Hewan uji yang digunakan adalah ikan baronang dengan bobot awal antara 30-32 g/ekor. Perlakuan yang dicobakan adalah pakan dengan: tanpa suplementasi S. cerevisiae (S0; kontrol), suplementasi S. cerevisiae 2% (S2), suplementasi S. cerevisiae 4% (S4), dan suplementasi S. cerevisiae 6% (S6). Wadah penelitian yang digunakan adalah waring hitam berukuran 1 m x 1 m x 2 m, dengan kedalaman air 1,5 m; ditebari ikan uji dengan kepadatan 20 ekor/wadah. Metode yang digunakan dalam penelitian ini adalah metode eksperimen dengan menggunakan rancangan acak lengkap (RAL). Pemberian pakan dilakukan dua kali sehari sebanyak 4% dari biomassa ikan uji. Hasil penelitian menunjukkan bahwa penambahan 2% S. cerevisiae dalam pakan memberikan respons pertambahan bobot dan laju pertumbuhan spesifik yang lebih tinggi (P<0,05) dibandingkan dengan perlakuan lainnya. Nilai koefisien kecernaan total pakan relatif sama antara perlakuan S2, S4, dan S6, namun ketiganya lebih tinggi dan berbeda nyata (P<0,05) dengan kontrol (S0). Jumlah sel darah merah (eritrosit) dan aktivitas fagositosis mengalami peningkatan secara signifikan (P<0,05) seiring dengan penambahan S. cerevisiae dibanding kontrol (S0). Suplementasi S. cerevisiae dapat dilakukan sebanyak 2% dalam formulasi pakan ini untuk pembesaran ikan baronang.The utilization of Saccharomyces cerevisiae supplemented in artificial feed of protein plant-based can increase the growth of several of aquaculture fish species. This study was aimed to evaluate the effect of S. cerevisiae supplementation in artificial diet on the growth performance of rabbitfish. The test animals used were rabbitfish with an initial weight of 30-32 g/fish. The treatments tried were artificial diets with: no supplementation of S. cerevisiae (S0; control), supplementation of S. cerevisiae 2% (S2), supplementation of S. cerevisiae 4% (S4), and supplementation of S. cerevisiae 6% (S6). The fish were reared in twelve net cages of 1 m x 1 m x 2 m, with a density of 20 ind./cage. Completely randomized design was used in this experiment. The fish were fed with test diets twice a day as much as 4% of total biomass. The results showed that the supplementation of 2% S. cerevisiae in diet gave higher weight gain and specific growth rate (P<0.05) than those of other treatments. The value of total feed digestibility coefficient was relatively the same between treatments S2, S4, and S6, but the three of them were higher and significantly different (P<0.05) than the control (S0). The number of red blood cells (erythrocytes) and phagocytic activity increased significantly (P<0.05) along with the supplementation of S. cerevisiae compared to control (S0). Supplementation of S. cerevisiae could be done as much as 2% in feed formulation for grow-out of rabbitfish.
Protein rich food waste could be used as raw materials for making fish feed pellets, which would diminish the volume of dumped waste into landfills. This study investigated the use of food waste (FW) based pellets composing of 75% food wastes derived from plant materials (cereals, fruit and vegetables) supplemented with yeast and the mixture of bromelain and papain to feed grass carp (Ctenopharyngodon idellus). Generally, improved growth performance (in terms of feed conversion ratio, protein efficiency ratio and relative weight gain) was observed in the diet groups supplemented with yeast (Saccharomyces cerevisiae). The most optimal dose was 25 g/kg yeast with enzymes (bromelain and papain, at the ratio of 1:1) and protein utilization was enhanced. Fish immunity was also stimulated, which indicated by the higher nitroblue tetrazolium and bactericidal activities. Moreover, resistance against Aeromonas hydrophilia was enhanced. It is envisaged that food waste could be widely used as feeds for culturing herbivorous fish and adding supplements such as baker's yeast and enzymes will further enhance the feed conversion ratio and fish immunity.
To investigate the course of Streptococcus iniae infection in Japanese flounder Paralichthys olivaceus, fish (average weight 118±14 g) were experimentally infected by oral and bath methods, and the distribution and multiplication of S. iniae in the fish were monitored by bacteriological and immunohistochemical examinations. S. iniae was detected first in relatively high numbers in the kidney and spleen. Viable counts of S. iniae in the blood, brain, liver, stomach, intestine, gill, skin mucus and nares were high only when those in the kidney and spleen were high. S. iniae-laden phagocytic cells were observed in the lumen of the blood vessels distributing in the organs and tissues in the initial stage of infection. Many fish showed hemorrhagic lesions on the fins, and the extracellular multiplication of S. iniae in the hemorrhagic fins was observed in the initial stage of infection. These observations were common among the fish challenged by either method. There was no evidence of the entrance of S. iniae through the stomach, intestine, gill, eye or olfactory pouches of nares. It was presumed that S. iniae entered directly from the water through the abrasive sites of fins and was disseminated by the blood circulation to cause systemic infection.
Practical diets that contain high levels of plant proteins often require supplementation with methionine to satisfy the total sulfur amino acid requirements of animals. The present study was designed to evaluate L-methionine, DL-methionine, N-acetyl-DL-methionine (acetylmethionine), and DL-methionine hydroxy analog (MHA) as supplements in soybean-meal-based diets for sunshine bass, the hybrid of white bass Morone chrysops ♀ × striped bass M. saxatilis ♂. Five practical diets were formulated to contain crude protein at 40% of dry weight, with 75% of the protein provided by soybean meal and 25% provided by menhaden fish meal. The basal diet provided total sulfur amino acids from intact protein at approximately 1.0% of dry diet, and the test diets were supplemented with each of the methionine compounds at 0.3% dry weight on an equal-sulfur basis (except for an additional 25% for MHA). A control diet was formulated to contain 40% crude protein exclusively from menhaden fish meal. All experimental diets were compared with a commercial diet containing 45% crude protein. Triplicate groups of juvenile sunshine bass (initial weights, 8–9 g/fish) were fed each diet in a brackish-water (5%) recirculating system for 8 weeks. Fish fed the soybean-meal-based diets supplemented with L-methionine, DL-methionine, and acetylmethionine had weight gains and feed efficiencies similar to fish fed the commercial and control diets. However, MHA was not efficiently utilized by sunshine bass, and performance of fish fed that diet was significantly (P < 0.05) reduced, as was that of fish fed the basal diet. The highest protein efficiency ratio values were observed for fish fed the control diet and the diets supplemented with L-methionine and DL-methionine. Whole-body protein and moisture were not affected by the dietary treatments; however, differences in whole-body lipid and ash were observed among some treatments.
To examine the prophylactic and therapeutic value of dietary vitamins C and/or E given in megadoses against disease, juvenile reciprocal-cross hybrid striped bass (female white bass Morone chrysops × male striped bass M. saxatilis) were fed experimental diets with 2,500 mg vitamin C/kg diet (100× the established dietary requirement), 300 mg vitamin E/kg (10× the dietary requirement), or both at the requirement or megadose levels for 3 or 6 weeks before and 0, 3, or 7 d after experimental exposure to Streptococcus iniae. The first dead fish was observed 3 d following intraperitoneal injection with S. iniae, and mortality did not appear to be significantly affected by dietary vitamin level or length of feeding. Infection with S. iniae reduced tissue total ascorbate and α-tocopherol levels at 14 and 21 d postinjection relative to those in uninfected control fish. Dietary vitamin E at 300 mg/kg significantly increased mortality when fed for 3 weeks before exposure. Additionally, dietary vitamin C at 2,500 mg/kg and vitamin E at 300 mg/kg tended to decrease the antibody titers of hybrid striped bass surviving infection, possibly indicating prooxidant effects of the megadose treatments. These observations suggest that dietary supplementation with megadose levels of vitamins C and/or E before or after infection with S. iniae is an ineffective treatment for juvenile hybrid striped bass.
Streptococcus iniae is an important bacterial pathogen of fish, causing up to 50% mortality in stocks, which has recently been associated with human infections. To determine whether S. iniae isolates from humans and fish are similar, the present authors examined the biochemical profiles and genetic relatedness of these isolates by random amplified polymorphic DNA (RAPD) analysis and repetitive primer polymerase chain reaction(REP PCR). The biochemical profiles differentiated between the human and fish isolates of S. iniae using pyrrolidonyl arylamidase, arginine dehydrogenase, ribose, β-glucoronidase and glycogen as markers. These biochemical results suggest that the fish and human S. iniae isolates are genetically different. However, RAPD and REP PCR do not have the discriminatory power to differentiate between these streptococcus isolates using five different RAPD primers and BoxA primer.
A study was undertaken to investigate the effects of graded dietary levels and different types of carnitine on hybrid striped bass (Morone chrysops ♀ × M. saxatilis ♂ %) fed different levels of lipid. An incomplete factorial design was utilized in which diets containing lipid at either 5 or 10% were supplemented with l-carnitine at 0, 500, or 1000 mg kg−1 diet, dl-carnitine at 1000 mg kg−1 diet, or carnitine chloride to provide 1000 mg carnitine kg−1 diet. Juvenile hybrid striped bass (3.3 g fish−1) were stocked into individual 38-l aquaria connected as a brackish water (6‰), recirculating system and fed each diet in triplicate for 9 weeks.
Supplementation of the diet with 1000 mg carnitine kg−1 increased muscle carnitine from 35.5 to 47.7 μg g−1 tissue. Carnitine supplementation did not result in increased weight gain regardless of carnitine level or type; however, weight gain showed a significant (p<0.05) response to dietary lipid with fish fed diets containing 10% lipid growing 34% more than fish fed diets with 5% lipid. The hepatosomatic index also was unaffected by diet, but the intraperitoneal fat (IPF) ratio was significantly elevated (5.1 vs 3.2%) in fish fed diets with 10% lipid compared to those fed diets with 5% lipid. Fish fed diets containing 1000 mg carnitine kg−1 had increased IPF ratio values at 4.7% compared to 3.9% for fish fed the basal diet. Liver lipid also was responsive to dietary treatment, increasing from 6.7 to 8.8% of wet weight as dietary lipid increased from 5 to 10%. The relative quantities of triglycerides, free fatty acids and phospholipids in muscle and liver were not influenced by carnitine level, carnitine type or dietary lipid level. Supplementation of carnitine does not appear to be beneficial to hybrid striped bass based on either growth performance or body composition.
Spent brewer's yeast was autolysed and the residual solids were further treated with hot alkali to produce a fraction containing 95% (w/w) carbohydrate, with a glycogen content of 42% and an apparent glucan content of ca. 53% (w/w). FTIR and solid state C-NMR spectra basically showed a spectrum characteristic for an impure -glucan. In vitro, this glucan induced release of prophenoloxidase from intact black tiger shrimp haemocytes. When fed to shrimp at 0.2% (w/w of the feed) for 3 days, significant increases in phenol oxidase, the number of haemocytes and the bacterial killing activity against the pathogen Vibrio harveyi were observed. Furthermore, this feeding resulted in the appearance of an inducible -(1,3)-glucanase in the liver. Methods to analyse the fractions are discussed and a number of commercial products with potential immune stimulating properties have been included for comparative purposes.
Two simple semiautomated microassays for the measurement of superoxide (O2−) and hydrogen peroxide (H2O2) production by cultured macrophages (MPs) are described. The measurement of O2− is based on the reduction of ferricytochrome c as assayed by the increase in its absorbance at 550 nm. Quantitation of H2O2 is based on the horseradish peroxidase (HRPO)-dependent oxidation of phenol red which is assayed by its increased absorbance at 600 nm. MPs are cultured in monolayers in 96-well flat-bottom tissue culture plates and covered with 100 μl amounts per well of either a ferricytochrome c solution or a solution containing phenol red and HRPO. Following the addition of an agent eliciting an oxidative burst (OB) and incubation of the plates at 37°C for various time intervals, the changes in the absorbance of ferricytochrome c and phenol red, respectively, are measured directly in the wells of the tissue culture plates with the cells in situ, by using an automatic 8-channel photometer which reads absorbances vertically through individual wells. This instrument, which was originally designed for reading enzyme immunoassays in microtitration plates, can be easily adapted for use in the above tests, when fitted with interference filters with wave lengths of 550 nm (for the assay of O2−) and 600 nm (for the assay of H2O2). The principal advantages of this techniques are: the ability to perform the assays directly in the culture plates with cells in situ; the small amounts of cells and reagents needed; its sensitivity and reproducibility; the ease with which kinetic experiments can be done; the large number of samples which can be tested in parallel, and especially the speed and convenience offered by the automated reading and printout of absorbance values.
The capability of Streptococcus iniae to cause disease in Japanese flounder was investigated by oral and bath (30 min) challenges with low, medium and high inoculation doses. Only with the highest inoculation dose, 9.9 x 10^7 CFU/100g body weight, the oral challenge induced deaths. In the bath challenge deaths were induced even at the lowest inoculation dose, 2.9 x 10^3 CFU/mL water. Hemorrhagic lesions on the fins were observed in dead fish challenged by both methods. It is suspected that S. iniae entered through the body surface such as abrasive sites of the fins to cause disease
We isolated for the first time Streptococcus iniae strains associated with diseased marine fish. Diseased red drum Sciaenops ocellatus were lethargic, and presented external signs (exophthalmia and loss of orientation) resembling those of freshwater fish infected by S. iniae. Skin lesions, extending to a necrotizing myositis, were typical of S. iniae infection of red drum. Histopathological findings indicate that S. iniae infection in red drum produces a chronic disease with systemic involvement characterized by multiple necrotic foci. Molecular epidemiology (RFLP [restriction fragment length polymorphism] ribotyping) revealed that 2 different ribotypes were involved in a single outbreak. The first is the EcoRI 'Israeli' trout and tilapine ribotype (Hind III type a strains), while the second is the EcoRI 'American' ribotype (Hind III type b strains), typical of tilapines farmed in Texas and Idaho.
Streptococcus iniae was isolated from 2 moribund wild Red Sea fishes, Pomadasys stridens (Pomadasyidae) and Synodus variegatus (Synodontidae), both collected in shallow waters along the Israeli coast of the Gulf of Eilat. The site is approximately 2 km from a mariculture cage farm in which streptococcal infections were diagnosed in previous years in the red drum Sciaenops ocellatus. This is the first report of S. iniae in Red Sea fishes. Biochemical and molecular similarities between the isolates from cultured fishes and those from the wild specimens suggest that a single strain is involved, and that 'amplification' and dispersal of this pathogen from captive to feral fishes have occurred. At the molecular level, the pathogen is different from the S. iniae isolates that have been afflicting the Israeli freshwater aquaculture in recent years. Although S. iniae prevalence in the wild fish populations of the area remains to be determined, the northernmost region of the Gulf of Eilat, virtually landlocked and with generally calm seas and weak currents, seems to be particularly vulnerable to the impact of diseases that develop in this mariculture system.
Juvenile rainbow trout, weighing 0.12g on average, were fed on diets containing 0.2 and 2mg/kg of peptidoglycan (PG) derived from bifidobacterium thermophilum at a ratio of 3% body weight (BW) for 56 days, so that fish were given 6μg or 60μg PG/kg BW per day. On days 28 and 56, fish were challenged by immersing them in Vibrio anguillarum suspension, and the mortality was monitored for 21 days. PG did not influence the growth of fish at these doses. On day 28, PG-administrated groups showed a significantly higher survival rate compared with the control group. On day 56, however, no significant difference in the survival rates was observed between the PG-administrated group and the control group at either dose. These results indicate that the oral administration of PG enhances the resistance of rainbow trout against V. anguillarum infection, and a longer administration of more than 28 days may lead to a decrease in disease resistance.
Vertebral deformity occurred in cultured marine fish, yellowtail (Seriola quinqueradiata) at an occurrence rate of 2.1 % from July to September, 1982 in Mie Prefecture. Eighteen deformed fish (11-15 cm in body length) were investigated with bacteriological, soft radiographical and histopathological technics. β-hemolytic streptococcal bacterium was dominantly isolated from the brain of the diseased fish and identified as Streptococcus iniae. The soft radiographical technic confirmed that the deformity was due to vertebral lordosis, kyphosis and scoliosis at the trunk and tail parts. The histopathology of diseased fish was characterized by a massive infiltration of cocci-laden macrophages and production of granulomas containing cocci in the third ventricle, maninges and granular layer of cerebellar cortex of the brain. There were also granulomas in the hepatec capsule and peritoneum. © 1984, The Japanese Society of Fish Pathology. All rights reserved.
To determine the effects of the inclusion of exogenous nucleotides in aquaculture diets on the resistance of fish to various challenge infections, trials were carried out and results presented. When added to normal fish feed formulations at a combined inclusion level of 0.03%, these additional nucleotides were shown to increase resistance to challenge infections with bacterial, viral and rickettsial diseases as well as ectoparasitic infestation. When fed for 3 weeks prior to challenge, the nucleotide-supplemented diet was superior (31% mortalities; relative percent survival: RPS=37%) to a β-glucan-containing diet (43% mortalities; RPS=12%) in reducing mortalities due to Vibrio anguillarum infection in fish fed the control diet (49% mortalities). Mortalities resulting from infections with infectious salmon anaemia (ISA) virus and Piscirickettsia salmonis were also significantly reduced (RPS=25.7% and 42.1%, respectively) as were the numbers of infesting sea lice (Lepeophtheirus salmonis) (37.8% reduction in the mean number of attached lice per fish). The mode of action of supplemental dietary nucleotides and advantages over recognised immunostimulants are discussed.
The potential of using yeast nitrogen in fish feeds to replace proteins from conventional sources is an attractive option to nutritionists, feed manufacturers and fish farmers. Experiments were conducted to determine the effects of high dietary levels of brewer's dried yeast, with 20% of its protein represented by nucleic acid nitrogen, on the growth, feed conversion efficiency and uric acid metabolism of rainbow trout (Oncorhynchus mykiss).Growth and liver uricase activities were monitored in trout fed diets containing 0, 25, 50 or 75% yeast. Growth was faster and feed conversion more efficient in fish fed diets consisting of 25% yeast; the diets containing 50 and 75% yeast were seemingly unpalatable to trout. Liver uricase activity, present in all fish, was directly correlated with the dietary level of nucleic acids. It was concluded that although feed intake was depressed at yeast levels greater than 25%, the fish did not appear to be adversely affected physiologically by high dietary levels of nucleic acid nitrogen.
Various immunostimulants and their methods of application in fish culture are examined in this review. Important variables such as life stage and innate disease resistance of the fish; immunostimulant used, its structure and mode of action; and the fish's environment are discussed. Conflicting results have been published about the efficacy of immunostimulants in fish diets. Some researchers have had positive responses demonstrated as increased fish survival, others have not. Generally, immunostimulants enhance individual components of the non-specific immune response but that does not always translate into increased fish survival. In addition, immunostimulants fed at too high a dose or for too long can be immunosuppressive. [Article copies available for a fee from The Haworth Document Delivery Service: 1-800-342-9678. E-mail address: [email protected]
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Proper nutrition plays a critical role in maintaining normal growth and health of cultured fish. A variety of nutritional strategies may influence fish health, including adjustment of specific nutrient levels in the diet, manipulation of nutritional condition through feeding regimens, and administration of non-nutrient immunostimulants in the diet. Research with several fishes, including some marine and diadro-mous species such as salmonids, has established that immunocompet-ence and disease resistance can be compromised by deficiencies of various nutrients, especially certain vitamins and minerals. Thus, adequate levels of these micronutrients must be supplied in prepared diets to support optimal growth and production efficiency of fish in aquacul-ture. In addition, dietary supplementation of some of these micronutri-ents in excess of minimum requirement levels has been shown to significantly enhance immune responses and disease resistance of various animals. Overfortification of such nutrients as vitamin C, vitamin E, and selenium have shown positive influences on immunity and disease resistance in some studies but no effects in other studies. Management practices that affect the nutritional condition of fish also may influence their health and ability to resist disease. Recent research with freshwater fish indicates certain feeding regimens, including moderate feed deprivation, alter a fish's resistance to disease. Such feeding regimens potentially may be applied to reduce losses of marine fish in aquacul-ture. Dietary supplementation of non-nutrient immunostimulatory compounds also has attracted considerable interest due to positive responses of several fish species in terms of non-specific immunity and disease resistance. Compounds such as −1,3-glucans which are derived from yeasts and fungi have been shown to change the activation level of different parts of the non-specific immune system, resulting in significantly reduced mortality after challenge with various pathogens. Some of these compounds have become commercially available in recent years, but their efficacy has been variable when administered in the diet. Specific examples concerning application of these various nutritional strategies in aquaculture are presented. Further advancements in these areas may allow nutritional modulation of the immune response to be used as an effective and relatively inexpensive alternative to chemical therapy in combating diseases of fish in aquaculture.
The cause of an ongoing mortality of hybrid tilapias Tilapia nilotica × T. aurea in a Texas fish farm was a biotype of Streptococcus iniae. Identification was based upon classical biochemical and physiological analysis as well as ribosomal RNA gene sequencing. The causative agent, a β-hemolytic Streptococcus species, grew better at 37°C than at 10, 25, or 40°C, and its growth was inhibited at pH 9.6, in 6.5% NaCl, and in 40% bile. The bacterium was resistant to ampicillin and furazolidone but was susceptible to several antibiotics including tetracycline, oxytetracycline, and sulfadimethoxine-ormetoprim (5:1). This is the first record of this bacterial species affecting fish in the USA. External signs of disease in tilapia were loss of orientation, exophthalmia, corneal opacity, and petechia around the mouth, anus, and proximal margins of the pectoral fins. Internally, fluid accumulation in the peritoneal cavity and enlargement of the liver, spleen, and kidney were observed.
Streptococcus iniae was found to be responsible for mass mortality in whitespotted rabbitfish Siganus canaliculatus in Bahrain. External signs were listless swimming and dark coloration. Internally, ascites, hepatomegaly, and splenomegaly were observed. Identification of the bacterium was based upon biochemical, physiological, serological tests and DNA–DNA hybridization. Host susceptibility was examined in five fish species. Rabbitfish was the species most susceptible to streptococcal infection. Borneo mullet Liza macrolepis and brown-spot grouper Epinephelus coioides were also susceptible to the bacterium, whereas the seabream Acanthopagrus latus (known in Bahrain as black seabream) and one-spot bream Diplodus sargus were not.
Immunostimulants are valuable for the control of fish diseases and may be useful in fish culture. The immunostimulatory effects of glucan, chitin, lactoferrin and levamisole for fish and shrimp have been reported. Nutritional factors such as Vitamins B and C, growth hormone and prolactin have also been reported to be immunostimulators. These immunostimulants mainly facilitate the function of phagocytic cells and increase their bactericidal activities. Several immunostimulants also stimulate the natural killer cells, complement, lysozyme and antibody responses of fish. The activation of these immunological functions is associated with increased protection against infectious disease. Resistance to bacterial pathogens such as Vibrio anguillarum, V. salmonicida, Aeromonas salmonicida, Yersinia rukeri and Streptococcus spp. and to parasitic infections such as white spot disease can be increased by administration of immunostimulants, but not to intracellular pathogens such as Renibacterium salmoninarum and Pasteurella piscicida. The most effective method of administration of immunostimulants to fish is by injection. Oral and immersion methods have also been reported, but the efficacy of these methods decreases with long-term administration. Overdoses of several immunostimulants induce immunosuppression in fish. The side effects of immunostimulants have not been well-studied. Growth-promoting activity has been noted in fish or shrimp treated with glucan or lactoferrin. Immunostimulants can overcome immune suppression by sex hormones. Thus, the influence of immunostimulants in mature fish should be studied. In conclusion, immunostimulants can reduce the losses caused by disease in aquaculture; however, they may not be effective against all diseases. For the effective use of immunostimulants, the timing, dosages, method of administration and the physiological condition of fish need to be taken into consideration.
An 8-week feeding trial to determine the effects of carbohydrate complexity on growth and body composition of advanced striped bass and sunshine bass fingerlings (80–85 g, initial weight) was followed by a digestibility trial to determine the effects on apparent digestibility coefficients (ADCs). Fish were fed semi-purified, isonitrogenous (35% crude protein), isolipidic (5%) diets containing either no soluble carbohydrate or glucose, maltose, or dextrin at 25% of diet. Weight gain and feed efficiency of sunshine bass was significantly greater than that of striped bass regardless of dietary treatment. Weight gain and feed efficiency of sunshine bass increased with decreasing molecular weight of dietary carbohydrate whereas only dextrin inclusion significantly increased (P
Previous studies have shown that intraperitoneal (i.p.) injection of a yeast cell wall glucan into Atlantic slamon, Salmo salar L., resulted in increased resistance to bacterial pathogens and that the glucan enhanced the protective effect of an i.p.-administered furunculosis vaccine in salmon. In the present work, the peritoneal cell responses to yeast glucan, glycogen, Freund's incomplete adjuvant (FIA) and saline were compared. Whereas saline gave no detectable peritoneal cell response, injection of the three other agents resulted in accumulation of macrophages, neutrophils and thrombocytes in the peritoneal cavity 2–22 days later. Glucan and glycogen gave maximum leucocyte responses 2 days after injection, whereas the number of leucocytes after FIA injection showed a continuous increase during the 22-day experimental period. Two days after injection, macrophages dominated in the leucocyte response to yeast glucan, whereas neutrophils dominated in response to glycogen and FIA. At 8 and 22 days post-injection of yeast glucan and FIA, thrombocytes represented the largest fraction of peritoneal cells. Except for an elevated number of neutrophils 3 weeks after injection, i.p. administration of yeast glucan gave no significant change in leucocyte numbers from the head kidney. On the other hand, head kidney macrophages from glucan-treated fish showed an increased ability to kill a virulent strain of Aeromonas salmonicida.
A trial was conducted to test the effect of partial replacement of fishmeal (Danish LT fishmeal - the only protein source in the control diet) by brewers yeast, in isonitrogenous (48% CP) and isoenergetic (22 MJ kg-1) diets for sea bass juveniles with an initial average weight of 12 g. Diets were formulated to include 0%, 10%, 20%, 30% or 50% of dietary N from yeast (diets D0, D10, D20, D30, D50, respectively); another diet supplemented with methionine (diet D50M) was also prepared. Each diet was distributed by hand to satiation to duplicate groups of 25 fish and the growth trial lasted 12 weeks. During the trial, feed intake (g kg-1 day-1) was identical in all groups. At the end of the trial growth rate was not significantly different among groups, except for the D50M diet, which was significantly lower than diet D30. Feed conversion was better for diets D10, D20 and D30, containing yeast than for the control diet. N retention (% N intake) was significantly higher in fish fed diets containing yeast (except for the D50M diet) than in those fed the control diet. There were no significant differences among groups in energy retention (% E intake). The protein content of the fish was significantly higher in fish fed diets containing yeast (except for the D50M diet) than in those fed the control diet. Apparent digestibility of the diets was determined in a separate trial with fish weighing 62 g. Feces collection was performed according to the Guelph system. Apparent digestibility coefficients of dry matter and energy significantly decreased with the increase of dietary yeast level. ADC of protein was significantly lower for the D50 diet than for the other diets. Results of this trial indicate that brewers yeast can replace 50% of fishmeal protein with no negative effects in fish performance. Moreover, the inclusion of up to 30% brewers yeast in the diet improved feed efficiency. There was no beneficial effect of supplementing the brewers yeast diets with methionine.
The activities of lysozyme, alkaline and acid phosphatase, N-acetyl-glucosaminidase and complement (as spontaneous haemolytic activity) were measured in plasma of Atlantic salmon, Salmo salar L., after intraperitoneal injection of a β-1,3 and β-1,6 linked glucan from Saccharomyces cerevisiae. The glucan has previously been shown to induce resistance of Atlantic salmon to several bacterial pathogens. The glucan treatment resulted in increased activities of lysozyme 1–3 weeks and complement 2–4 weeks after injection. The activities of alkaline phosphatase and N-acetyl-glucosaminidase showed a decrease 1 week after injection and then slowly restored to normal levels, whereas acid phosphatase was only slightly altered during the experimental period. These results indicate that the glucan induces a selective increase in lysozyme rather than a general release of lysosomal enzymes. The time intervals of enhanced activities of lysozyme and complement partially overlapped with the time intervals of expected enhanced protection against pathogens. Thus, induction of increased activities of lysozyme and complement may, at least in part, explain the mechanisms by which glucan induces protection against bacterial pathogens in salmon.
Streptococcus iniae infection was evaluated in hybrid striped bass and tilapia following experimental, bilateral inoculation of a virulent isolate of S. iniae onto their eyes or into their nares. Inoculation of eyes did not result in mortality or disease signs in either species. In contrast, mortality and disease signs were observed in both species following nares inoculation. Hybrid striped bass were susceptible to 4.8×103S. iniae colony forming units (CFU), an inoculum 100 times lower than that affecting tilapia. We observed decreased mortality of hybrid striped bass administrated 4.8×105 CFU dose of S. iniae. Following S. iniae infection, the disease signs observed in hybrid striped bass and tilapia were erratic, serpentine, rising and falling, and head-up swimming, slow acceptance or refusal of food, lethargy and darkened skin. We did not observe exophthalmia, eye opacity or body curvature. We were able to recover S. iniae from either nares, eyes, brains, or head kidney of 87.5% and 66.7% of the morbid hybrid striped bass and tilapia, respectively. Both hybrid striped bass and tilapia produced significant anti-streptococcal titers 14 days post nares inoculation with 4.8×103 CFU of S. iniae. Successful experimental S. inaie infection of fish following nares inoculation suggest that nares may be a potential route of S. iniae infection in cultured fish species. This route of experimental infection for S. iniae has not been previously described in fish.
Immunostimulant preparations Macrogard®, Candida utilis, Saccharomyces cerevisiae, Evetsel®, Chitosan®, or FinnStim® were mixed into semipurified diets and fed to groups of rainbow trout for 1 week. Fish were bled by non-lethal caudal puncture and blood samples assayed for changes in non-specific cellular immunity and humoral protein levels. In the immunostimulated fish, hematocrit levels and lymphocyte counts remained relatively stable; however, elevations were observed in oxidative radical release, myeloperoxidase activity, phagocytic indexes, and potential killing activities of phagocytic cells including neutrophils. Total plasma protein and total immunoglobulin levels were elevated by the dietary immunostimulants. A challenge with the virulent pathogen that causes furunculosis, Aeromonas salmonicida, showed that the immunostimulated groups of fish were more resistant to the disease, confirming the potential use of these substances in fish culture for the prevention of disease.
Some epizootiological aspects of a bacterial septicemia of hybrid tilapia (Tilapia nilotica X T. aurea) caused by a biotype of Streptococcus iniae were investigated. Bacterial growth in Brain Heart Infusion broth was detected at 10, 25, 35 and 45 °C, between pH 5.5–8.5, and at salinities of up to 30 ppt. After suspension of the bacteria in distilled water, viable cocci were recovered for up to 5 days at 5 °C and < 24 h at 25 °C. The 96 and 168 h LD50 in 30–90 g fish was found to be 4.9 × 105 and 3.18 × 105 colony forming units (injected intraperitoneally), respectively. Artificial infection was achieved through oral administration as well as by dipping fish in water containing the bacterium. Greater rates of mortality were observed in artificially infected tilapia maintained at 20 °C than those kept at 15, 25, 30 or 35 °C; and in water of pH 9 compared with fish maintained in more acidic water. Sodium azide based selective media were not successful at recovering any viable cells from earthen growout-ponds that had contained infected fish. Hybrid striped bass were found susceptible whilst red drum and channel catfish were resistant to artificial infection.
We evaluated the effectiveness of Streptococcus iniae vaccines prepared from formalin-killed cells and concentrated extracellular products (greater than 2 kDa) of a single isolate of S. iniae (ARS-10) and a combination of ARS-10+ARS-60 S. iniae isolates in tilapia, Oreochromis niloticus, for the prevention of streptococcal disease. Two routes of administration, intraperitoneal (i.p.) and intramuscular (i.m.) injection, were evaluated for vaccine efficacy. Tilapia were vaccinated by i.p. or i.m. injection of the vaccine or tryptic soy broth (control) and challenged by i.p. injection with 1×108 colony-forming units of S. iniae 30 days post-immunization. Tilapia i.p. immunized with ARS-10 vaccine and challenged with the homologous isolate (ARS-10) had a relative percent survival (RPS) of 45.6%. Tilapia i.p. immunized with ARS-10 vaccine and challenged with a heterologous isolate (ARS-60) had an RPS of 93.7%. In contrast, we found that the RPS was 17.7% in tilapia i.m. immunized with the ARS-10 vaccine and challenged with the same isolate, ARS-10. Heterologous (ARS-60) isolate challenge resulted in an RPS of 59.5%. However, the i.m. administration of a vaccine combining the ARS-10+ARS-60 isolates provided an RPS of 63.1 against ARS-10 isolate and RPS of 87.3% against ARS-60 isolate in comparison to RPS of 17.7 and 59.5 against ARS-10 and -60 isolates provided by the single isolate ARS-10 vaccine. Vaccination significantly reduced abnormal behavior and morphology. We found a highly significant (P<0.01) negative correlation between the behavioral and morphological score and RPS. Serologic evaluation revealed that both i.p. and i.m. immunizations stimulated significant (P<0.05) antibody titers in comparison to the non-immunized tilapia. Significantly (P<0.05) increased antibody titers were also produced by i.m. immunization of the combined ARS-10+ARS-60 vaccine. Administration of the single isolate ARS-10 vaccine by i.m. injection was marginally protective in preventing streptococcal disease caused by homologous and heterologous isolates of S. iniae. The variability seen in the protective ability of a single S. iniae isolate vaccine indicates that antigenic heterogeneity exist in S. iniae. Recognition of this antigenic variability is very important to development of efficacious streptococcal vaccines. Thus, this research suggests that efficacious vaccines, that may be administered by either i.p. or i.m. injection, are dependent on the antigenic composition of the S. iniae.
Schizophyllan and scleroglucan, which are β-1,3-glucans derived from Schizophyllum commune and Sclerotium glucanicum, were evaluated for their ability to enhance protection against bacterial infection in yellowtail. Intraperitoneal injections of the β-1,3-glucans (2–10 mg/kg) into fish 6 and 3 days prior to intraperitoneal challenge with Streptococcus sp. resulted in a significantly increased survival rate, but the injection did not enhance resistance against Pasteurella piscicida. In β-1,3-glucan-treated fish, an elevation of serum complement and lysozyme activity was observed in addition to an increase in the phagocytic activity of pronephros cells. This suggests that the β-1,3-glucans enhanced the resistance of yellowtail against Streptococcus sp. infection through the activation of the non-specific immune system. The ineffectiveness of the β-1,3-glucans in enhancing the resistance against P. piscicida is discussed.
This article provides a broad overview of microbial pathogens associated with marine and fresh water aquatic animals, including Vibrio species, Escherichia coli, Streptococcus iniae, Salmonella species, and Edwardsiella tarda. Historically, cultured fish were not considered important vectors of human pathogens. This situation is changing, partly due to increasing animal densities as a consequence of a rapidly growing industry and partly due to increasing awareness by health care providers of pathogens in aquatic species that may result in human illness. Concerns facing the industry are also discussed along with possible solutions.
Two kinds of selective agar were developed for the isolation of Streptococcus iniae, the causal agent of streptococcosis, from Japanese flounder (Paralichthys olivaceus) and from culture tanks in flounder farms. The selective agars were heart infusion agar with added thallium acetate and oxlinic acid (TAOA), and colistin sulphate and oxolinic acid (CSOA). For samples containing various bacterial flora, selective agars were supplemented with defibrinated horse blood in order to distinguish beta-haemolytic colonies of Strep. iniae. Streptococcus iniae was quantitatively isolated from the brain and kidney of diseased flounders in pure culture. Two-thirds of isolates picked up from selective blood agars inoculated with intestinal samples were identified as Strep. iniae. The bacterial colony numbers of deposits and water from culture tanks on selective blood agars were about 10-10(5) times smaller than those on control heart infusion agar; Strep. iniae was isolated from few deposit and water samples.
Clinical and macroscopic findings (anorexia, lethargy, loss of orientation and exophthalmia) indicate that Streptococcus iniae and Lactococcus garvieae infections of trout share some common features, but histopathology reveals notable differences between the 2 diseases. Meningitis and panophthalmitis are the main lesions among S. iniae infected trout, whereas L. garvieae infection results in a hyperacute systemic disease. Differences in the LD50s of the 2 pathogens and the sudden onset of signs and death correlate with the histopathological findings, indicating the severity of L. garvieae infection of trout.
To examine the mechanism by which vitamins C and E alter phagocyte function, a series of in vitro manipulations were conducted with cells isolated from the head-kidney of hybrid striped bass (average weight 680 g) fed a diet supplemented with minimum requirement levels of vitamins C and E for 2 weeks. Head-kidney phagocytes were cultured in media containing physiologically deficient (23 microM, adequate (45 microM) or excessive (182 microM) concentrations of vitamin C, and physiologically deficient (5 microM), adequate (9 microM) or excessive (32 microM) concentrations of vitamin E for 18 h. Following culture and stimulation, levels of reactive oxygen intermediates and hydrogen peroxide were determined. There were no effects of vitamin C or vitamin E concentrations on hydrogen peroxide or extracellular O2- generation. Intracellular O2- production, however, was significantly (P < or = 0.05) affected. When vitamin C was supplied at deficient levels to the medium, vitamin E elevated O2- production to levels not different from those of cells incubated with requirement levels of both vitamins. Similarly, when vitamin E was deficient in the media, vitamin C supplementation at requirement levels normalised intracellular O2- production. This data provides support for the presence of a vitamin C and vitamin E sparing mechanism in phagocytic head-kidney cells of hybrid striped bass and yield some insight into the mechanisms by which vitamin C and vitamin E function in immunomodulation.
Juvenile hybrid striped bass (initially 12.0 g) were fed diets containing deficient, adequate or excessive amounts of vitamin C and/or vitamin E in a factorial arrangement to investigate potential nutritional interaction and effects on immune responses. Nine semipurified diets were supplemented with 0, 25 or 2500 mg vitamin C/kg and 0, 30 or 300 mg vitamin E/kg and fed to fish in triplicate aquaria for 10 wk. Weight gain, feed efficiency, mortality and tissue vitamin levels were significantly (P < or = 0.05) affected by dietary vitamin levels. In addition, a significant interaction between vitamin C and vitamin E was observed. At inclusion levels of 25 and 2500 mg/kg, dietary vitamin C improved feed efficiency and protected fish fed vitamin E-deficient diets from growth depression and mortality. At inclusion levels of 30 and 300 mg/kg, vitamin E prevented mortality in fish fed vitamin C-deficient diets; however, 300 mg vitamin E/kg was necessary to prevent growth depression in vitamin C-deficient fish but was unable to improve feed efficiency. Lysozyme, bacterial killing ability, as well as plasma protein and total immunoglobulin levels of fish were not affected by dietary vitamin levels, whereas respiratory burst activity increased with vitamin E supplementation. Thus, interactions between vitamin C and vitamin E were observed in hybrid striped bass. These interactions may be due to the ability of vitamin C to regenerate vitamin E to its functional form but also suggest an ability of vitamin E to spare vitamin C.
Hybrid striped bass (Morone chrysops X Morone saxatilis ) are an important aquaculture species yet there are few diagnostic tools available to assess their health. Hematology and clinical chemistry analyses are not used extensively in fish medicine due to the lack of reference intervals for various fish species, and because factors such as age can affect blood values. There is little published information regarding age-related changes in blood values of juvenile fish. It is important to evaluate juvenile fish, as this is the time they are raised in aquaculture settings. Determining age-related changes in the blood values of fishes would further develop clinical pathology as a diagnostic tool, enhancing both fish medicine and the aquaculture industry. The results of standard hematology and clinical chemistry analysis were evaluated in juvenile hybrid striped bass at 4, 6, 9, 15, and 19 months of age. Values for PCV and RBC indices were significantly lower, and plasma protein concentration was significantly higher in younger fish. Total WBC and lymphocyte counts were significantly higher in fish at 6 and 9 months of age, while neutrophil and monocyte counts were higher at 6, 9, and 15 months. Eosinophil counts were significantly higher in 9-month-old fish. The majority of hematologic values fell within previously established reference intervals, indicating that only slight modification to the intervals is necessary for evaluating hematologic results of hybrid striped bass at different ages. The following analytes deviated sufficiently from adult reference intervals to warrant separate reference values: plasma protein concentration at 4 months, WBC and lymphocyte counts at 15 and 19 months, and thrombocyte-like-cells at 9 months of age. Values for most biochemical analytes were significantly different among age groups except for creatinine and potassium concentrations. Comparisons with reference intervals were not made for biochemical analytes, because established reference intervals were not available. Age-related changes in hematologic and biochemical values of striped bass were similar to those reported for rainbow trout and mammals.
Immunohistochemical examination of experimental Strepto-coccus iniae infection in Japanese flounder Paralichthys olivaceus Partial replacement of fishmeal by brewers yeast Saccaromyces cerevisae in diets for sea bass Dicentrarchus labrax juveniles
- P Li
- D M Gatlin
- H T Rnguyen
- K Kanai
- K Yoshikoshi
P. Li, D.M. Gatlin III / Aquaculture 219 (2003) 681–692 691 rNguyen, H.T., Kanai, K., Yoshikoshi, K., 2001b. Immunohistochemical examination of experimental Strepto-coccus iniae infection in Japanese flounder Paralichthys olivaceus. Fish Pathol. 36, 169–178. Oliva-Teles, A., Goncalves, P., 2001. Partial replacement of fishmeal by brewers yeast Saccaromyces cerevisae in diets for sea bass Dicentrarchus labrax juveniles. Aquaculture 202, 269–278
Diseases in Asian Aquaculture: II. Fish Health Section
- M Shariff
- J R Arthur
- R P Subasinghe
Shariff, M., Arthur, J.R., Subasinghe, R.P. (Eds.), Diseases in Asian Aquaculture: II. Fish Health Section.
Asian Fisheries Society, Manila, pp. 413 – 426.