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The significance of lipids at early stages of marine fish: A review
Abstract
The present work reviews the significance of lipids at different early stages of marine fish larvae. Lipids in broodstock nutrition are considered to be important for the quality of the larvae. Lipids affect the spawning and the egg quality of many fish species and a deficiency in (n−3) highly unsaturated fatty acids (HUFA) in broodstock negatively affects fecundity, fertilization rate and hatching rate of the species studied. Lipids as a source of energy at the embryonic and larval stage (before first-feeding) are evaluated in relation to other sources of energy such as protein and carbohydrates. After hatching and prior to first-feeding, some marine species show a preference in catabolizing phosphatidylcholine, whereas phosphatidylethanolamine tends to be synthesized. The effect of long-term (LT) and short-term (ST) enrichment techniques on the lipid composition of rotifers has been documented using various marine oils/emulsions. The quantitative and qualitative lipid class and fatty acid composition of diets influenced the lipid and fatty acid composition of both LT- or ST-enriched rotifers. The nutritional improvement of Artemia is also important and may follow the general methods used for rotifers. The functions of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) during early stages of marine fish larvae are apparently different. High amounts of EPA in relation to DHA may create an imbalance in the structural composition of the phospholipids, which could affect the normal growth and the quality of the larvae. Turbot larvae tended to exhibit lower pigmentation success with lower DHA:EPA ratio in the total lipid fraction of the larvae, especially when the absolute amounts of EPA were high compared to those of DHA (in the total lipid and phospholipid fraction of the larvae). Considerable research is necessary to clarify many aspects regarding the function of these fatty acids, especially how their content at the egg stage can affect further requirements for normal growth and survival.
... PLs play a crucial role as structural components within the lipid bilayer of cells, underscoring their importance in early development for cellular formation. Rainuzzo et al. [39] also emphasized the conservation of PLs across various marine fish larvae species due to their significance in maintaining cell membrane integrity. In this study, the PL content remained stable during the growth and development of yolk-sac larvae but then significantly decreased. ...
... Studies have demonstrated that marine fish exhibit a selective utilization pattern of fatty acids during the prefeeding stage of larval development [39,51]. Gunasekera et al. [52], studying the early development of Macculochella macquariensis (trout cod), found that the order of fatty acid utilization was SFAs, MUFAs, n-6 PUFA, and n-3 PUFA. ...
Simple Summary
This study assessed changes in the biochemical composition of hybrid grouper during the early larval stages. Samples were collected at various developmental stages, ranging from newly hatched larvae to 4 days after hatching. The findings reveal several key observations: (1) The total length of hybrid grouper larvae exhibited a significant increase as the yolk-sac absorption progressed from stage I to V. (2) Dry weight and total lipid content exhibited a rapid decrease throughout larval development. (3) Significant reductions were observed in the levels of triacylglycerols and wax esters/steryl esters. (4) Throughout yolk-sac larval development, a notable decrease occurred in the concentrations of essential amino acids, including leucine, valine, isoleucine, phenylalanine, glycine, alanine, serine, proline, and tyrosine. (5) There was a significant decrease in the levels of specific fatty acids, such as C16:0, saturated fatty acids (SFAa), monounsaturated fatty acids (MUFAs), C18:0, 18:1n-9, and C20:4n-6. Conversely, the levels of C22:6n-3, polyunsaturated fatty acids (PUFAs), n-3 PUFA, n-6 PUFA, and the combination of docosahexaenoic acid (DHA) + eicosapentaenoic acid (EPA), as well as the DHA/EPA ratio, remained stable from stage I to III but decreased thereafter. (6) During the early developmental stages, the utilization sequence of fatty acids followed a pattern of SFAs, MUFAs, n-6 PUFA, and n-3 PUFA. These results provide further insights into the varying efficiency of utilization among different types of fatty acids and highlight relatively stable protein utilization with selective consumption of amino acid content during hybrid grouper larval development.
Abstract
To investigate the shifts in the biochemical composition of hybrid grouper during the early larval stages, we collected samples at various developmental milestones, spanning from newly hatched larvae (stage I) to 4 days after hatching (stage V). Our findings revealed several notable trends: (1) The total length of hybrid grouper larvae exhibited a significant increase as the yolk-sac absorption progressed from stage I to V. Concurrently, there was a marked decrease in yolk volume and oil volume during the transition from stage I to III, followed by a gradual decline from stage III to V. (2) Dry weight and total lipid content displayed a rapid reduction throughout the larval development period, while the total protein content exhibited a declining trend. (3) The concentrations of triacylglycerols and wax esters/steryl esters decreased considerably, particularly at stage V. However, no differences were observed among the contents of ketones, hydrocarbons, and sterols. (4) As yolk-sac larvae developed from stage I to V, a significant reduction was observed in the levels of essential amino acids (EAAs), such as leucine, valine, isoleucine, phenylalanine, glycine, alanine, serine, proline, and tyrosine. This trend was also observed for non-EAAs and total amino acids, with fluctuations in the content of other amino acids. (5) There was a significant decrease in the levels of specific fatty acids, including C16:0, saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), C18:0, 18:1n-9, and C20:4n-6. In contrast, the contents of C22:6n-3, polyunsaturated fatty acids (PUFAs), n-3 PUFA, n-6 PUFA, and the combination of docosahexaenoic acid (DHA) + eicosapentaenoic acid (EPA), as well as the DHA/EPA ratio, remained stable from stage I to III but declined thereafter. (6) During the early developmental stages, the utilization sequence of fatty acids followed a pattern of prioritizing SFAs, followed by MUFAs, n-6 PUFA, and n-3 PUFA. These findings provide further insights into the nutritional priorities of hybrid grouper larvae during their early development, with a particular emphasis on lipids and fatty acids as vital energy sources. Additionally, our results highlight variations in the efficiency of utilization among different types of fatty acids, while protein utilization remained relatively stable, characterized by the selective consumption of amino acid content.
... A diet low in DHA contributes to the decline of cognitive abilities with age and to the onset of several diseases such as attention deficit hyperactivity disorder, cystic fibrosis, phenylketonuria, unipolar depression, aggressive hostility, and adrenoleukodystrophy. 53 For marine animals, this fatty acid, like others in the PUFA family, is essential for reproductive function, and a deficient nutrition in these fatty acids will affect the broostock fecundity, fertilization, hatching rate and viability of the eggs, as well as growth and development of larvae of marine organisms. 54,55 In this work, relatively high values of DHA were observed in the gonads of sea urchins fed with formulated fed. For those fed with macroalgae, the values were very low. ...
... 57 Also, an imbalance in the structural composition of the phospholipids caused by a higher quantity of EPA in comparison to DHA could compromise the larvae's normal growth and quality. 54 For human health foods with different DHA/EPA ratio can be used depending on the nutritional strategy. A diet with DHA:EPA in the ratios of 1:1 and 2:1 reduced inflammation and oxidative stress primarily at the 1:2 ratio. ...
Sea urchin gonads are a prized gourmet product in many areas of the globe, and wild populations are threatened by increasing demand, making this species a very desirable product in aquaculture. Due to the unique needs of each stage of the life cycle, a viable food protocol that seeks to satisfy each stage while optimizing production profitability is required. The objective of this work was to test a formulated feed for sea urchins, through the analysis of somatic growth, gonad development and their fatty acid profile. These results were compared with sea urchins fed natural food (Ulva spp.) At the end of the trial Paracentrotus lividus juveniles fed inert diet had higher total wet weight gain, total specific growth rate, and gonadosomatic index than those fed with macroalgae. However, histological observations did not reveal differences in the maturation state of the gonads. In comparison to sea urchins fed fresh Ulva spp., inert diet showed higher total wet weight gain and higher total specific growth rate. Fatty acid contents of the gonads of each treatment were found to be similar. The DHA levels in the gonads of sea-urchins fed the formulated feed were significantly higher. It was possible to record the biosynthesis activity of some fatty acids such as 20:4 ω 6, 16:4 ω 3, and 20:3 ω 3. It was found that the presence of some essential fatty acids, such as DHA and EPA, in the gonads is only dependent on the food profile. The addition of a DHA-rich ingredient in the formulated feed may have been preponderant in the constitution and development of the sea-urchins’ gonads.
... The methods for enrichment of live prey have provided great advances in the successful culture of larvae of marine species. Different modalities of formulations, with different compositions, have been used such as emulsions and/or liposomes (Hontoria et al., 1994;Rainuzzo et al., 1997;Navarro et al., 1997;Monroig, 2006), to which additives such as antibiotics, probiotics, and vitamins, among others, can be added (Lazo et al., 2000;Cahu & Zambonino-Infante, 2001). Several authors have used vitamins in Pagrus major larvae (Temminck & Schlegel, 1843) (Kolkovski, 2001;Ogata & Oku, 2001;Teshima et al., 2004;Hernández et al., 2006), Sparus aurata larvae (Henrique et al., 1998;Fernández et al., 2008;Gonzáles et al., 1995;Izquierdo et al., 2018), Acanthopagrus latus larvae (Houttuyn, 1782) (Adlo et al., 2012), and larvae of flatfishes such as Scophthalmus maximus (Linnaeus, 1758) (Estévez & Kanazawa, 1995), Solea senegalensis (Kaup, 1858) (Fernández et al., 2009;Fernández, 2017), Paralichthys olivaceus (Temminck & Schlegel, 1846) (Dedi et al., 1995). ...
... Gapasin et al. (1998) studied Chanos chanos larvae (Forsskål, 1775) using live food fortified with vitamin C at doses of 33 mg/g obtaining the best values between 24-27 mg dry weight at 40 DAH, being this dose higher than those recommended for larvae of the order Perciforme (Izquierdo et al., 2018) to which A. scapularis belongs; nevertheless, the dry weight values coincide with those found in the E1 and E2 treatments. Betancor et al. (2012) reported total weight values of 1.01 ± 0.07 mg and length of 11.24 ± 1.08 mm at 21 DAH in Dicentrarchus labrax larvae with doses of 3,600 mg/kg of vitamin C, being the weight and length values lower than those found in treatment E3 and E4 as they obtained the lowest growth compared to the other treatments and the dose used was Los métodos de enriquecimiento de las presas vivas han proporcionado grandes avances en el éxito del cultivo de larvas de especies marinas, empleándose diferentes modalidades de uso de formulaciones de composición diversa, como emulsiones y/o liposomas (Hontoria et al., 1994;Rainuzzo et al., 1997;Navarro et al., 1997;Monroig, 2006), a los cuales se puede añadir aditivos como antibióticos, probióticos y vitaminas, entre otros (Lazo et al., 2000;Cahu & Zambonino-Infante, 2001). Se han empleado vitaminas en larvas de diferentes especies como: Pagrus major (Temminck y Schlegel, 1843) (Kolkovski, 2001;Ogata & Oku, 2001;Teshima et al., 2004;Hernández et al., 2006), Sparus aurata (Henrique et al., 1998;Fernández et al., 2008;Gonzáles et al., 1995;Izquierdo et al., 2018), Acanthopagrus latus (Houttuyn, 1782) (Adlo et al., 2012) y de peces planos como Scophthalmus maximus (Linnaeus, 1758) (Estévez & Kanazawa, 1995), Solea senegalensis (Kaup, 1858) (Fernández et al., 2009;Fernández, 2017) así como Paralichthys olivaceus (Temminck y Schlegel, 1846) (Dedi et al., 1995). ...
El desarrollo larval de peces obtenidos en cautiverio, se encuentra relacionado a nutrición, y búsqueda de técnicas de habituación a dietas comerciales. En tal sentido, la presente investigación está dirigida a conocer el efecto de adicionar vitaminas a un enriquecedor comercial para conocer su influencia en crecimiento, supervivencia, presencia de malformaciones y perfil bioquímico en larvas de Anisotremus scapularis. Se utilizaron 1500 larvas, con 2,19 ± 1,30 mg de peso seco y 3,00 ± 0,23 mm de longitud total inicial, que fueron sembradas en tanques de 100 L a densidad de 10 larvas/L, con una mezcla de microalgas Nannochloropsis oceanica e Isochrysis galbana. Se elaboraron 4 tratamientos; teniendo como base al enriquecedor comercial Selco Spresso®, al que se añadieron las vitaminas: Enriquecedor 100 g (E1), Enriquecedor 99,95 g + 45.000 μg/100g vit A (E2), Enriquecedor 99,63 g + 45.000 μg/100g vit A + 180.000 μg/100g vit C + 136.000 μg/100g vit E (E3) y Enriquecedor 99,63 g + 180.000 μg/100g vit C + 136.000 μg/100g vit E (E4) y fueron añadidos al alimento vivo 6 h antes de ser suministrados a las larvas. La alimentación inició 2 días después de la eclosión (DDE) con Brachionus plicatilis hasta el día 20 DDE y luego con nauplios de artemia hasta el 35 DDE cuando inició el destete, agregando alimento inerte micro particulado comercial hasta el 60 DDE que finalizó el experimento. La calidad del agua del cultivo larval se mantuvo según parámetros del laboratorio: temperatura (19,9 ± 0,71 °C), pH (8,58 ± 0,37), oxígeno disuelto (7,33 ± 0,46 mg/L) y porcentaje de saturación (80,53 ± 4,68%). Al final del experimento, se obtuvieron promedios del peso total 29,22 ± 8,18 mg; longitud total 18,68 ± 8,53 mm; tasa de crecimiento específico 4,36 ± 0,51%g/día, supervivencia 42,78 ± 5,98%, malformaciones 11,72 ± 7,80%, DHA/EPA 0,87 ± 0,09. Los tratamientos no presentaron diferencias significativas (p > 0,05); sin embargo, el tratamiento E2 obtuvo los mejores resultados. Este estudio nos permitió conocer la influencia de las vitaminas en el desarrollo de larvas de Anisotremus scapularis bajo condiciones de laboratorio, asimismo las vitaminas utilizadas deberían servir como base para realizar otros ensayos que nos acerquen a conocer la nutrición larval de chita.
... In teleost fish, reproduction requires high energy, mainly in the form of lipids, which is used for the actual reproductive processes, the formation of gamete membranes and the constitution of yolk reserve (Lubzens et al., 2017;Tocher, 2003). Reproductive success and offspring survival are associated to lipid quality and availability for gamete synthesis (Marshall et al., 1999;Rainuzzo et al., 1997). Lipid quality is a central element because lipids have vast physiological functions: they act as structural component of (i) cell membranes and signalling pathways, mainly in the form of phospholipids (which are polar lipids; PL), cholesterol, and essential fatty acids, and (ii) energy storage, mainly in the form of triacylglycerol and sterol esters (which are neutral lipids; NL). ...
... Essential fatty acids are long chain polyunsaturated fatty acids (LC-PUFA) necessary for the correct organism function, but that consumers cannot synthetize in sufficient quantity to meet their health requirements and that must thus be acquired by their diet. Among LC-PUFA, optimal concentrations and proportions (ratios) in gonads of 20:5n-3 and 22:6n-3 (n-3 LC-PUFA family), and 20:4n-6 (n-6 LC-PUFA family), have been shown to promote fecundity, egg hatching and viability, and larvae survival (Koven et al., 2018;Lubzens et al., 2017;Rainuzzo et al., 1997). Furthermore, 22:6n-3 is especially required for neural membrane formation in brain and eyes (Koven et al., 2018;Morais et al., 2011), while 20:5n-3 and 20:4n-6 mediate the inflammatory response and reproduction processes through the production of eicosanoids and prostanoids (Chapkin et al., 2009;Xu et al., 2022). ...
Swordfish Xiphias gladius is a large pelagic fish distributed worldwide and exploited for human consumption, however there is limited knowledge about its reproductive biology, especially regarding lipid dynamic in gonads. In teleost fish, reproductive success and offspring survival are associated to lipid availability for gamete synthesis. This study investigated the lipid composition, including lipid classes and fatty acids (FA) of cell membrane and reserve lipids (i.e., polar and neutral lipids, respectively; PL and NL), along female and male gonad development of a swordfish population from waters surrounding Corsica Island in the Mediterranean Sea. Overall, swordfish gonads contained <2% wet weight of total lipids, with testes and ovaries having similar fat content. Lipid classes and FA concentrations remained unchanged during testes maturation. However, concentrations of phosphatidyl choline (PL), triacylglycerol (NL), and some FA (16:0, 18:1n-9, and 22:6n-3) followed an “inverted U-shaped” relationship with the ovarian maturation. In both PL and NL, 22:6n-3 was the main polyunsaturated FA (>20% of total FA), while 20:5n-3 and 20:4n-6 were minor (3–6% of total FA) and varied little with maturation. 22:6n-3 and 18:1n-9 were selectively allocated to the ovarian maturation (increased in concentration and in proportion with maturation) until spawning. Finally, swordfish gonads might represent a good food source for humans given that 150 g of swordfish ovaries can cover the daily requirements in omega-3 for humans, but research on pollutants should also be conducted to evaluate their implications on the reproduction output of this species, and on the safety of swordfish gonads for human consumption.
... A importância de se conhecer o tipo e a quantidade de lipídios na dieta de animais, devido a sua influência na qualidade e quantidade de AGPI nos tecidos e nas células, foi salientada por Rainuzzo et al. 34 . Os lipídios para a nutrição de peixes foram exaustivamente estudados nas últimas duas décadas. ...
No Brasil tem ocorrido crescimento vertiginoso na criação de peixes de cativeiro de água doce; no entanto existem poucos estudos sobre identificação e quantificação de ácidos graxos em pescados provenientes de cativeiro. Sabe-se que entre diversos fatores, a dieta alimentar do peixe é o fator determinante sobre sua composição lipídica, especialmente quanto aos componentes de ácidos graxos. O objetivo deste trabalho foi de efetuar a revisão de vários estudos, com o intuito de obter um panorama sobre a composição dos ácidos graxos em pescado e, ainda, quanto à influência da dieta sobre a composição de ácidos graxos dos peixes capturados em ambiente natural e dos cultivados em diferentes sistemas. A maioria dos estudos aponta que a composição de ácidos graxos em peixes marinhos apresenta maiores proporções de ácidos graxos poliinsaturados Omega 3 (AGPI- ω 3) do que os peixes de água doce. O ácido graxo palmítico e o oléico atingem os mais altos níveis no pescado de água marinha e de água doce. Na maioria dos peixes, o DHA, o EPA e a-linolênico são as maiores fontes de AGPI ω 3, enquanto o linoléico e o araquidônico contribuem como fonte de AGPI ω 6.
... On the other hand, when this ratio was inversed, deformities diminished. Key physiological processes like growth, immunity, survival, pigmentation development (Copeman et al., 2002;Montero et al., 2010;Sotoudeh et al., 2016), as well as brain and retina development (Furuita et al., 1998;Rainuzzo et al., 1997) need the presence of eicosapentaenoic acid (EPA; 20:5ω-3) and DHA. In addition, LC PUFA support cellular membrane functions such as membrane transport, enzymatic activity and nuclear receptor activation (Roo et al., 2009;Tocher, 2003). ...
... It is a well known fact that brood stock nutrition has significant effects on gonadal growth, fecundity, fertilization, hatching rate and viability of eggs. Superior nutrition for the broodstock will be of particular importance in ensuring yolk quality for the proper endogenous nutrition of the developing embryonic larvae which has direct implications on the quantity and quality of weaned fingerlings produced [28]. While formulations to ensure optimal fecundity, gamete quality and larval survival have been attained in other species [36], for cobia no such information is available on optimized brood stock diets, and this clearly represents an important limitation which demands immediate attention. ...
Among the many candidate local species identified for development of aquaculture in the United Arab Emirates (UAE), cobia (Rachycentron canadum) has the great potential for farming in floating cage systems. Successful spawning and rearing of larvae and juveniles was first achieved by the Aquaculture and Marine studies Center, Abu Al Abyad Island, Abu Dhabi in 2008. The first trial to grow cobia in near shore cages of 55 m³was done in 2009 when the stocked fish reached an average weight of 2.87 kg in 12 months rearing period. Subsequently two more attempts were carried out in larger 15 meter diameter (636 m³) cages in 2022, the results of which were not encouraging. There are many challenges for the development of cobia farming in UAE. This article highlights the current technological challenges, sustainability issues, marketing strategies and policy matters that confront the development of commercial cobia aquaculture in the UAE and offers some recommendations.
... The potential use of lipids and proteins in the physiological processes of marine fishes has been studied by several authors who have highlighted the temporal dimension of these macronutrients during reproductive periods (Bradford, 1993;Rainuzzo et al., 1997;Zudaire et al., 2014;Hiraoka et al., 2019;Sardenne et al., 2022). Thus, Henderson et al. (1984) described that during the pre-reproductive period of female capelin Mallotus villosus, the lipid contents of the muscle and liver decreased, while those of the gonad increased. ...
The temporal dynamics of energy reserves are associated with the physiological processes (i.e., reproduction) in marine fishes, in which storage organs play a key role for efficient energy investment. We evaluated the temporal (i.e., seasons) and intra-individual (i.e., organs) dynamics of adult female swordfish (Xiphias gladius) during its feeding period off the Chilean coast in the southeastern Pacific Ocean (SEPO). The biochemical composition (i.e., lipids, proteins, and glucose), energy content and fatty acid profile of the muscle, liver and gonad were evaluated during the austral autumn, winter, and spring. Our results showed principally an intra-individual effect in both the muscle and liver in the autumn and spring. Herein, a trend of higher amounts of lipids and total energy were found in the muscle, while the liver showed greater protein and glucose contents. Consequently, the muscle showed a higher saturated, monounsaturated, and polyunsaturated fatty acid contents than the liver. Although the gonad showed no significant temporal effect in the lipids and proteins contents, an increasing trend of each biochemical constituent, fatty acid group and gonadosomatic index were found from autumn to winter. Consistently, the glucose and total energy content as well Fulton's condition factor were significantly higher in winter. These findings reflect the spatial-temporal physiological dynamic of swordfish based on the storage of energy reserves in different organs during its feeding period. In this way, the products obtained from swordfish could have an added value depending on the season and capture zone, which could benefit the exploitation and regulation measures of this resource under an ecological approach of conservation and sustainability in the SEPO.
... Essential fatty acids (EFAs) are exceptionally important in human nutrition and also in fish reproduction (Soivio et al. 1989, Rainuzzo et al. 1997, Adams 1999, Glencross 2009). Requirements for EFAs vary with habitat (marine, brackish, or freshwater) since freshwater fishes can synthesize long-chain polyunsaturated fatty acids (LC-PUFA) from the 18-C fatty acids linolenic acid (C18:3 n-3, aLNA; C18:3 n-6, gLNA) and linoleic acid (C18:2 n-6, LOA). ...
The fatty acid (FA) compositions of eggs from wild whitefish and captive broodstocks were investigated to estimate the FA requirements of Coregonus maraena. The aim of this study was to increase basic knowledge on the nutritional needs of broodstock. Whitefish eggs from two natural spawning grounds were compared with that of captive broodstocks that were fed three commercially available feeds used in fish farms in Mecklenburg-Vorpommern, Germany. Wild fish eggs differed significantly in crude protein content and FA profiles from the eggs of experimentally farmed fish groups. The percentage of monounsaturated FAs (MUFA) were significantly lower in the wild fish eggs. The most common MUFA was oleic acid in all groups, although in the wild fish eggs the value of it was almost half of that in farmed fish eggs. Wild fish eggs had significantly higher values of total polyunsaturated FAs (PUFA), especially of n-3 PUFA, which was nearly double that of the eggs of the farmed fish groups. Additionally, it was shown that egg FA composition even differed between the wild fish stocks that were from the same area, whereas there were no differences in egg proximate composition or FA composition among the three feeding groups even though the compositions of the feeds fed to these fish differed significantly. The present study suggested that the proportions of essential FAs supplied in the dry feeds fed to the captive broodstocks were inappropriate for this species, and feeds must be adapted further to meet the nutritional requirements of this species to improve the quality of farmed whitefish eggs.
... Tỷ lệ sống cao hơn khi ấu trùng được cho ăn thức ăn làm giàu n -3 HUFA cũng được báo cáo trên các loài cá chẽm [1], cá đù (Argyrosomus regius) [20] và cá cam sọc (Seriola dumerili) [34]. Thiếu hụt DHA trong khẩu phần ăn đã ảnh hưởng tiêu cực đến sự hình thành và hoạt động của một số cơ quan (thần kinh, thị giác, vận động…) làm gia tăng các biểu hiện bất thường về tập tính ăn mồi, bơi đi kèm tỷ lệ dị hình và hao hụt cao trong quá trình ương [24,33]. ...
DHA và các axít béo không no có vai trò quan trọng trong việc cải thiện kết quả ương ấu trùng cá biển nói chung. Trong nghiên cứu hiện tại, các hàm lượng DHA làm giàu thức ăn sống khác nhau (50, 100, 150 và 200 mg/L và đối chứng 0 mg/L) được thử nghiệm nhằm đánh giá ảnh hưởng lên tốc độ tăng trưởng, tỷ lệ sống và tỷ lệ biến thái của ấu trùng cá khoang cổ cam. Ấu trùng cá khoang cổ cam được ương trong các bể kính 30 lít với mật độ 1 con/ 1,5 lít nước. Ấu trùng được cho ăn thức ăn sống làm giàu DHA (A1 DHA Selco), gồm luân trùng (3 ngày đầu) và metanauplius Artemia (từ ngày thứ 2 trở đi). Thí nghiệm được thực hiện với 3 lần lặp trong thời gian 45 ngày. Kết quả nghiên cứu cho thấy việc bổ sung DHA làm giàu ở bất kỳ hàm lượng nào (50 – 200 mg/L) cũng cải thiện đáng kể tốc độ tăng trưởng, tỷ lệ sống và biến thái của ấu trùng cá khoang cổ cam so với đối chứng (P < 0,05). Trong đó, hàm lượng bổ sung 150 mg/L được xác định là tối ưu. Việc gia tăng hàm lượng lên mức 200 mg/L không những không cải thiện mà còn làm giảm kết quả ương so với mức 150 mg/L. Từ nghiên cứu này có thể kết luận rằng ấu trùng cá khoang cổ cam nên được cho ăn thức ăn làm giàu DHA (150 mg/L) nhằm đạt được các chỉ tiêu tăng trưởng, tỷ lệ sống và biến thái tối ưu.
... 11KT is responsible for ovarian lipid accumulation in eels, since elevated lipoprotein lipase (Lpl) levels were found after an increase in 11KT [10]. Lipid quantity and composition are key determinants of egg quality in marine fishes [11]. 11KT also induces the expression of the ovarian fshr [8] and stimulates the production of the phospholipoglycoprotein vitellogenin (Vtg; [12]). ...
To induce oocyte development, eels are weekly injected with salmon or carp pituitary extract (CPE). The weekly handling and hormone peaks result in inferior oocyte quality; therefore, alternative treatments that improve oocyte quality and reproductive success require investigation. The enhancement of early sexual maturation by a single injection with human chorionic gonadotropin (hCG), administered prior to CPE treatment, was investigated. Fifty feminized eels were subjected to simulated migration, after which eels received either a hCG or a sham injection. After two months, the hCG-treated eels showed an increase in eye size, gonadosomatic index (GSI), and plasma 11-ketotestosterone concentration, when compared with the sham-injected controls. The hCG-treated eels showed increases in oocyte diameter and lipid area, and in ovarian expression of aromatase (cyp19), follicle stimulating hormone receptor (fshr) and lipoprotein lipase (lpl). Yolk was present in the oocytes of the hCG-treated eels, not yet in the oocytes of the controls. The hCG-induced deposition of yolk may relate to early-life treatment with 17β-estradiol during feminization. hCG-treated eels required four CPE injections less to mature than the controls. hCG treatment may benefit reproductive success in feminized eels by initiating vitellogenesis and reducing the hypophysation period, although larvae were obtained from most females in both groups.
... For marine fish, the PUFAs are essential FAs as these fish lack the appropriate FA desaturases for the synthesis of ω3 and ω6 FAs (Tocher, 2003). Generally, the main ω3 FAs, EPA and DHA not only promote gonad maturation, fecundity, egg viability and the survival of fish larvae (Furuita et al., 2000;Mourente & Odriozola, 1990;Rainuzzo et al., 1997;Watanabe, 1982), but can also be used as energy reserves for development and reproduction (Sargent et al., 2003). The GAM results showed that there was no significant effect of DHA on energy density in muscle and gonad tissues (Figures 4 and 5), suggesting that DHA might preferentially contribute to the maintenance of the membrane phospholipid structure during sexual maturation rather than serving as energy sources (Mourente et al., 1991;Sargent et al., 1999). ...
The energy density and fatty acid composition profiles of the muscle and gonad tissues of female mackerel icefish Champsocephalus gunnari from the South Orkney Islands in Antarctica were investigated throughout ovarian development to better understand the reproductive allocation strategy and the role of specific fatty acids in the reproductive process. Energy density in gonads increased from resting to spawning stages as the ovaries developed (19.60–25.10 kJ g⁻¹ dry mass [DM]). In contrast, energy density in muscles remained constant throughout ovarian development (20.13–22.87 kJ g⁻¹ DM), suggesting that the spawning events of the C. gunnari rely on energy income from feeding rather than on the energy stored in body. In addition, the variation in fatty acid composition between muscle and gonad tissues may reflect the role of main FAs as energy source. These results suggest that C. gunnari may utilize an income breeding strategy.
... Moreover, in the present investigation, the lipase activity was initiated at 1 DPH. It is associated with lipid catabolism to provide the energy for developing larvae and is highly essential for larval development (Rainuzzo et al., 1997). ...
Anabas testudineus is one of the potential candidates for species diversification in freshwater aquaculture. The present study aimed to evaluate the consumption pattern of endogenous nutritional components available in the form of yolk and digestive enzymes status during early larval development of A. testudineus. The fatty acid profiles viz., saturated fatty acid (SFAs), monounsaturated fatty acid (MUFAs), polyunsaturated fatty acid (PUFA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachidonic acid (ARA), n-3/n-6 ratio of eggs and different stages of unfed larvae of Anabas were determined. The digestive enzyme activities were also studied from the day of fertilization to the 25-day post-hatching (DPH). The results indicated that the MUFAs were the predominant fatty acid available in eggs and all the larval stages. The total MUFAs, n-6 contents and DHA: EPA were decreased significantly (p<0.01) from the eggs to 6 days old non-feeding larvae. Total n-3, EPA, DHA, ARA and ARA: EPA were significantly increased (p<0.01) in developing larvae. Surprisingly, EPA and DHA contents were significantly less (p<0.05) during 0 to 2 DPH and increased later on from 3 to 6 DPH. Proteases like trypsin and chymotrypsin activities were significantly (p<0.01) increased from the day of fertilization and they reached a peak on 15 DPH and 12 DPH, respectively and then a decreasing trend was observed up to 21 DPH. However, the pepsin activities were negligible up to 12 DPH and subsequently increased from 15 to 25 DPH. In contrast to pepsin, the lipase activities increased from day of fertilization to 12 DPH, then decreases up to 18 DPH and increased thereafter. Amylase activities were negligible (p<0.05) up to 2 DPH, then increased from 3 DPH to 18 DPH followed by significantly reduced (p<0.05) from 18 to 25 DPH. The culture potential of this species has not realized so far due to the lack of sufficient quantity of quality seed and the non-availability of appropriate larval feed. To produce a good quality larval feed, the basic knowledge on nutrient requirement of larvae is the prerequisite. Therefore, the present investigation revealed the activities of digestive enzymes and utilization of total fatty acids from the day of fertilization to 25 DPH in the early larval development of Anabas testudineus which are very much essential for developing the quality larval diets for this species.
... In L. lentjan, the specific lipase activity was detected in hatchling; after initial ups and down, it steadily increased till 13 dph; later on, a slight decline in the activity was seen. Lipase activity in the early stage is essential for proper larval development because lipids are energy sources during the endogenous feeding period in most of the marine species (Sargent et al., 1989;Sargent, 1999;Rainuzzo et al., 1997;Tocher and sergeant, 1984). Oozeki and Bailey, (1995) suggested the existence of two types of lipase, one in early yolk sac absorption and other in later stages of exogenous lipids digestion. ...
Ontogenetic development of the digestive tract and associated organs of Lethrinus
lentjan larvae was were learned by observing changes in external morphology,
histology, and enzymatic changes from hatchling to 40-day post-hatching (dph).
Ontogenetic development of the L. lentjan digestive system can be divided into three
major stages; the first stage from hatching of larvae to complete absorption of yolksac, which ends on 2 dph, the second stage from 3 to 15 dph i.e., from exogenous
feeding to the formation of the gastric gland and third stage till completion of
metamorphosis (35 dph). Pyloric caeca were developed after 20 dph, which was
formed entirely by 27 dph. Enzymatic activities of amylase, lipase, trypsin and
chymotrypsin were detected before the onset of exogenous feeding and pepsin was
detected from 19 dph onwards in L. lentjan. So considering both histology of digestive
tract and enzyme development, weaning of L. lentjan larvae to artificial diet can be
practiced after 19-20 dph coinciding with the formation of pyloric caeca and
production of pepsin enzyme for better digestibility and consequently better growth
and survival. The present study can be expended as a reference guide to understand
the digestive tract development and successful hatchery rearing of other economically
important marine fishes
... In general, marine fish have poor capability to synthesize essential fatty acids, which indicates that a dietary supplement of these nutrients is crucial (Coutteau et al., 1997;Rainuzzo et al., 1997;Mejri et al.). The specific requirement on highly unsaturated fatty acids (HUFAs) could be a consequence of evolution in marine trophic relationships. ...
... A diet low in DHA contributes to the decline of cognitive abilities with age and to the onset of several diseases such as attention de cit hyperactivity disorder, cystic brosis, phenylketonuria, unipolar depression, aggressive hostility, and adrenoleukodystrophy. (Horrocks and Yeo, 1999). For marine animals, this fatty acid, like others in the PUFA family, is essential for reproductive function, and a de cient nutrition in these fatty acids will affect the broostock fecundity, fertilization, hatching rate and viability of the eggs, as well as growth and development of larvae of marine organisms (Rainuzzo et al., 1997;Watanabe, 1993). In this work, relatively high values of DHA were observed in the gonads of sea urchins fed both inert foods. ...
Sea urchin gonads are a prized gorumet product in many areas of the globe, and wild populations are threatened by increasing demand, making this species a very desirable product in aquaculture. Due to the unique needs of each stage of the life cycle, a viable food protocol that seeks to satisfy each stage while optimizing production profitability is required. The objective of this work was to test a formulated feed for sea urchins, through the analysis of somatic growth, gonad development and their fatty acid profile. These results were compared with sea urchins fed natural food ( Ulva spp.) At the end of the trial Paracentrotus lividus juveniles fed inert diet had higher total wet weight gain, total specific growth rate, and gonadosomatic index than those fed with macroalgae. In comparison to sea urchins fed fresh Ulva spp ., inert diet showed lower feed conversion ratios and higher protein efficiency ratios. Fatty acid contents of the gonads of each treatment were found to be similar. The DHA levels in the gonads of sea-urchins fed the formulated feed, were significantly higher. It was possible to record the biosynthesis activity of some fatty acids such as 20:4 ω6, 16:4 ω3, and 20:3 ω3. It was found that the presence of some essential fatty acids, such as DHA and EPA, in the gonads is only dependent on the food profile. The addition of a DHA-rich ingredient in the formulated feed may have been preponderant in the constitution and development of the sea-urchins’ gonads.
... Besides, the fatty acid profiles of the fractionated lipids in some fish eggs, such as A. japonicus [20,31], H. trimaculatus [19], Coilia reynaldi [35], Clupea harengus [36], Oncorhynchus mykiss [37], Diplodus vulgaris [38] and Conger conger [38] were also detected. However, the lipid content and composition of fish eggs were clearly discovered to be different among different fish species during the different developmental stages, environment, season and diets [37,39]. As shown in Fig. 1A, the neutral lipids were found to be palmitic acid (C16:0, 23.13%), oleic acid (C18:1n-9, 17.85%), EPA (C20:5n3, 13.48%), and DHA (22:6n3, 19.26%). ...
In the present study, total lipids were extracted from Ammodytes personatus eggs and separated into neutral lipids, glycolipids, and phospholipids. The anti-inflammatory activity of the neutral lipids, glycolipids, and phospholipids was investigated in macrophages, as well as the fatty acid profiles of the lipids. Palmitic acid, oleic acid, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) were the primary fatty acids in the three fractionated lipids. Among the lipids, the phospholipids contained the highest concentration of polyunsaturated fatty acids (PUFAs), particularly DHA and EPA (31.89 and 16.93% of the total fatty acids, respectively). The anti-inflammatory effects of the three lipids isolated from A. personatus eggs were analyzed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The three lipids significantly reduced nitric oxide (NO) production and the mRNA expression of immune-associated genes in a dose-dependent manner. All lipids down-regulated the protein expression of phosphorylated NF-κB-p65 and MAPK (p38, JNK, and ERK1/2) signaling pathways, suggesting that they could inhibit cell signaling pathways by activating NF-κB and MAPK. The expression of CD40 and CD86 in LPS-stimulated RAW264.7 cells was also significantly decreased by A. personatus lipids. Conse-quently, the neutral lipids, glycolipids, and phospholipids from A. personatus eggs could serve as anti-inflammatory agents.
... However, in recent years, the mass culture and use of the latter two species has gained momentum as their consumption by some freshwater fish larvae provided superior results compared to an inert diet (Awaïss and Kestemont 1997;Lim and Wong 1997;Sales 2011;Ogata 2017). Several researches have indicated that the fatty acid profile of rotifers was below the optimal requirements of most cultured larvae and that the quantitative and qualitative lipid class and fatty acid composition of rotifer diets dictates the lipid and fatty acid composition of both long-term and short-term enriched rotifers (Rainuzzo et al. 1997;Theodorou 2018). In addition to the essential fatty acids, a study by Hamre et al. (2016) showed that micronutrient contents like vitamin A, E, C and thiamine were also below the levels found in copepods, which are the standards for enrichment of larvae raised on a yeast-based diet. ...
The artificial propagation of commercially important fish species in Ethiopia is constrained by high mortality rate at the early stage of larval rearing and a subsequent poor growth performance during later stages. This is mainly due to absence of live feeds suited to the requirements of the larvae of the species. Although not organized, several studies have indicated that microalgae, copepods, cladocerans and rotifers are the dominant inhabitants in several water bodies that are the precursors in the larviculture of commercially important finfishes in the world. However, apart from studying the abundance and diversity of these important planktonic organisms, efforts made to culture any of them for use in the larviculture of commercially important fish species in Ethiopia is minimal. This may be due to the lack of comprehensive and organized information on the distribution and abundance of these important species in the context of their potential in aquaculture of live feeds in Ethiopia. The objective of this review is therefore to compile the available information on the abundance and distribution of the major potential live feed organisms in the Ethiopian water bodies with a special emphasis on freshwater live feed organisms currently used in larviculture of commercially important freshwater finfishes. In line with this, four potential live feeds (i.e. microalgae, rotifers, copepods and cladocerans) were included in the review. It is hoped that the review will provide baseline information for future research in the culture of economically important larval live feeds.
... This is due to the unfavourable biochemical composition of Artemia, requiring their enrichment before using them as first feeds. 179,180 In addition, the size of Artemia is too large for early feeding in many fish larvae with very small mouths. Furthermore, Artemia is harvested in the wild (in salt lakes) and its availability is subject to variation due to climatic factors and other parameters, leading to varying or, even worse, increasing prices of this feed item. ...
Aquaculture has been one of the fastest‐growing food production systems sectors for over three decades. With its growth, the demand for alternative, cheaper and high‐quality feed ingredients is also increasing. Innovation investments on providing new functional feed alternatives have yielded several viable alternative raw materials. Considering all the current feed ingredients, their circular adaption in the aquafeed manufacturing industry is clearly of the utmost importance to achieve sustainable aquaculture in the near future. The use of terrestrial plant materials and animal by‐products predominantly used in aquafeed ingredients puts a heavily reliance on terrestrial agroecosystems, which also has its own sustainability concerns. Therefore, the aquafeed industry needs to progress with functional and sustainable alternative raw materials for feed that must be more resilient and consistent, considering a circular perspective. In this review, we assess the current trends in using various marine organisms, ranging from microorganisms (including fungi, thraustochytrids, microalgae and bacteria) to macroalgae and macroinvertebrates as viable biological feed resources. This review focuses on the trend of circular use of resources and the development of new value chains. In this, we present a perspective of promoting novel circular economy value chains that promote the re‐use of biological resources as valuable feed ingredients. Thus, we highlight some potentially important marine‐derived resources that deserve further investigations for improving or addressing circular aquaculture.
... sitions of rotifer lipids have been researched for decades (reviewed by Kotani, 2017). Lipid enrichment dynamics have been studied in response to different feeding regimens, commercial products (Eryalçın, 2018;Fernández-Reiriz et al., 1993;Rainuzzo et al., 1997), microorganisms (Kotani et al., 2010;Lubzens et al., 1995;Maruyama et al., 1997), triacylglycerols versus ethyl esters versus phospholipids and dose size/delivery times Li & Olsen, 2015). In all of these studies, enrichment is measured using gas chromatography (GC) analysis of fatty acid methyl esters (FAME)-a time-consuming, multi-step process, usually beginning with oil extraction into mixtures of chloroform:methanol:water followed by acid-or base-catalysed derivitization to methyl esters (Christie, 1982). ...
Improving the lipid composition of feed‐rotifers enhances the survival and growth rates of juvenile fish in aquaculture, but monitoring enrichment profiles using gas chromatography (GC) is slow, labour‐intensive and requires expensive instrumentation. Here, we describe the potential of Raman spectroscopy as an alternative, more rapid tool for quantitation of rotifer fatty acid composition in an aquaculture setting. A compositionally diverse sample set was prepared by periodically subsampling rotifers undergoing enrichment using three different feeding regimens. Sampled rotifers were freeze‐dried and their fatty acid content and composition was measured by GC–MS (mass spectrometry). Raman spectra (1064 nm excitation) were acquired with two instruments: a state‐of‐the‐art Fourier transform (FT)‐Raman spectrometer equipped with a liquid nitrogen‐cooled Germanium detector; and a smaller, portable spectrometer equipped with an InGaAs detector. Fatty acid reference data acquired by GC–MS were related to structured variance in each Raman spectral data set using partial least squares regression. The resultant models could accurately quantitate total fatty acids (TFA) and total polyunsaturated fatty acids (PUFA) using both FT‐Raman spectra (Root Mean Square Error [RMSEV] = 5.0 mg g−1 TFA and 6.1 mg g−1 PUFA) and spectra generated using the portable instrument (RMSEV = 4.2 mg g−1 TFA and 5.3 mg g−1 PUFA). Analysis times with the portable instrument were approximately 3 min, compared to 16 min with the FT‐Raman system. Portable Raman spectroscopy may be a useful tool for high throughput screening of rotifer lipid composition when testing and optimizing enrichment protocols and developing microdiets for aquaculture species.
... At the same time, the composition and content of fatty acids varied with fish species (Shi et al., 2010;Huang et al., 2013). Rainuzzo et al. (1997) believed that for larvae starting exogenous nutrition, the ideal fatty acid composition in the diet should be similar to that of fertilized eggs or yolk-sac larvae. Evaluating the utilization of endogenous yolk-sac nutrients during embryonic and early larval development was an effective method of studying the nutritional requirements of larvae (Lanes et al., 2012;Huang et al., 2020). ...
An estimation of the utilization of endogenous nutrients from the yolk sac that occurs during embryonic and early larval development can be a valuable approach to studying the nutritional requirements of fish larvae. In this study, fertilized eggs, embryos (before the membrane, 24 hours after fertilization), newly-hatched larvae (0-d-old), and open-mouthed larvae (3-day-old, unfed rotifers) samples of cobia (Rachycentron canadum) were collected to determine the amino acid and fatty acid profiles. Crude protein composition varies significantly for cobia during the different stages of development. The total amino acids, except for lysine(Lys), histidine (His), methionine(Met), serine(Ser), and glycine(Gly), had no significant change in the early development stage (P > 0.05); the content of other six essential amino acids (EAA) and six non-essential amino acids (NEAA) was consistent with the changing trend of total essential amino acid. From hatching newly hatched larvae to open-mouthed larvae, except for Leu, Phe and Ser, decreased significantly (P<0.05). From the utilization rate of FAA, the utilization rate of Lys and Leu was the highest (60.26%) and (52.21%) in the embryonic and endogenous nutritional stages, respectively. The water content of the open-mouthed larvae of cobia was significantly higher than that of the fertilized eggs, embryos, and newly hatched larvae (P < 0.05). Three kinds of saturated fatty acids (SFA), five kinds of monounsaturated fatty acids (MUFA), and eight kinds of polyunsaturated fatty acids (PUFA) were detected in the dry samples of each developmental stage. Based on these results, juvenile cobia can thrive with a wide range of crude protein concentrations. Further refinement of commercial cobia production feeds would have beneficial consequences for economic and environmental concerns due to the positive impacts of optimizing the protein component as well as the ability to maintain the rapid growth rates. The results show that the larval development of cobia needs to consume large amounts of n3PUFA (especially DHA and EPA) to improve the larvae’s survival rate. Research methods will always have limitations when evaluating the relationship between early life nutrition interventions and well-being outcomes later in life. This study provides essential information regarding cobia larvae’s fatty acid requirements.
... The analyses showed that the lumpfish ova were mostly composed of TAGs with some phospholipids (PEs and PCs), which is in line with lipid composition of other fish eggs (Wiegand, 1996). PCs serve as both an energy reserve and are, together with PEs, the main source for structural lipids in fish eggs (Cejas et al., 2004;Rainuzzo et al., 1997;Wiegand, 1996). Ova from wild-caught females trended towards having higher TAG content, being significantly higher in NR compared to LS-BS-2 (p > 0.0001) and LS-BS-3 (p = 0.0258). ...
Lumpfish (Cyclopterus lumpus) serves an important role as cleaner fish for removing salmon lice in salmon aquaculture. For this use, cultivated lumpfish are preferred over wild-caught fish to avoid overexploitation of natural stocks and provide a stable production of good quality eggs and larvae. To support this, high quality eggs containing the necessary building blocks to support high fertilization success, development into a normal embryo and high hatching success is needed. Ova from wild-caught and captive lumpfish females were collected and assessed to identify how wild and domesticated lumpfish differ in terms of ova lipid profiles, egg and larvae quality. Wild-caught lumpfish displayed higher fertilization and hatching success compared to captive lumpfish, whereas other biological variables like egg size, egg/larvae dry weight and respiration, and larval morphometry, were not significantly different between wild and captive lumpfish. Ova lipid profiles (total lipid, lipid classes, fatty acid composition and lipidomics) can separate egg batches based on their geographic origin of wild-caught females and composition of diets used for captive broodstock (lipid and carbohydrate content). Multivariate statistics were applied to identify lipid markers that can be used to predict the quality of lumpfish ova. Lumpfish ova lipidomic profiles covaried with several biological parameters, indicating that the former can be used to predict the latter. Lumpfish eggs were mostly composed of triacylglycerides (TAGs) with some phosphatidylethanolamines (PEs) and phosphatidylcholines (PCs), and their lipid profiles were more sensitive to the different origins, mother weight/size and fertilization success than variables such as eggs size or larvae morphometric measures. PC and PE content of lumpfish eggs were positively correlated to both hatching success and fertilization rates, thus the lipidomic profiles, with some key highlighted lipid species were putative predictors of egg quality.
... Broodstock must be fed a good-quality diet for several months before spawning (Rainuzzo et al., 1997). In this feeding trial, dietary algae inclusion as a replacement of fish meal resulted in a significant increase in reproductive performance (total fry production) of guppy. ...
In this study, fishmeal was partially replaced by Nannochloropsis sp. to evaluate its effect on growth, proximate composition, pigment and reproductive performance in guppy. Commercial feed and formulated diets with Nannochloropsis sp. incorporated at different levels were used for comparative study. Results showed that the lipid profile was significantly (P < 0.05) higher in 15 % inclusion of Nannochloropsis sp. whereas there was no significant (P > 0.05) differences in protein and carbohydrate content among all groups. However, feed conversion ratio, specific growth rate, average daily gain, length increment and condition factor were relatively similar in all groups except 15 % and commercial feed. The carotenoid content of fin and muscle was significantly (P < 0.05) higher in 15 % inclusion. In addition, the fish in 15, 10, and 5 % inclusions performed significantly (P < 0.05) earlier breeding with a higher number of offspring, respectively than the control and commercial feed fed groups.
... Knowing the first feeding requirements is a crucial factor influencing successful breeding in the majority of marine fish aquarium species (Koven et al., 1999;Rainuzzo et al.,1997;Rønnestad et al., 1999Rønnestad et al., , 2003. The urgent need for fast growing in economic species, such as A. bicinctus, is that the larval diet must match each energetics and nutritional needs. ...
Two experiments were performed in this investigation. The first was
established to compare the use of enriched rotifers (EROT) against
AF Artemia (AF Art) for substituting rotifer as start feeding for Clownfish
larvae and lasted 7 days. The observations showed a relatively lower capture
rate in AF Art treatments on 1st day, although, the intake and assimilation of
AFArt nauplii were clearly observed. Accordingly, growth and survival data
were non-significant. The second was performed on larvae from 8-21 days after
hatching (DAH), evaluating the enrichment impact of EG Art with four
microalgae spp., Chlorella salina, Tetraselmis chuii, and a novel trail
(Rhodomonas salina) which represented as (CEA, TEA& REA), respectively
against Nannochloroposis oculata (NEA) as control concerning growth
performance, pigmentation, metamorphosis and survival. Additionally,
detection of unsaturated fatty acids grouping mainly omega3 ratios in various
enriched Artemia was performed. Results revealed that the percentage of PUFA,
HUFA and n-3 fatty acids were significantly higher (p<0.01) in (REA)
compared with (TEA) followed by (NEA) & (CEA), respectively. Otherwise,
DHA/EPA and EPA/AA ratios were promoted in REA then NEA whereas no
values for DHA/EPA were detected in both TEA & CEA treatments due to
DHA absence. Larvae group C4 achieved maximum growth of 111.06 ± 0.2mg;
on contrary (C2) attained the lowest results. In C4 group; metamorphosis took 9
days, while it extended to 10, 11, and 12 days in C1, C3, and C2, respectively.
However, the onset pigmentation of larvae was surpassed in TEA followed by
REA within 3-4 days from the beginning of the experiment shorter than NEA.
Moreover, the C4 group achieved the highest survival of 80 ± 2.4%, while C2
attained the lowest records. This study authenticated the possibility of using AFArt
as the first feed to facilitate breeding intricacy as also suggested R.
salina alga enrichment as a prime candidate for improving the Clownfish
industry.
... Knowing the first feeding requirements is a crucial factor influencing successful breeding in the majority of marine fish aquarium species (Koven et al., 1999;Rainuzzo et al.,1997;Rønnestad et al., 1999Rønnestad et al., , 2003. The urgent need for fast growing in economic species, such as A. bicinctus, is that the larval diet must match each energetics and nutritional needs. ...
Two experiments were performed in this investigation. The first was established to compare the use of enriched rotifers (EROT) against AF Artemia (AF Art) for substituting rotifer as start feeding for Clownfish larvae and lasted 7 days. The observations showed a relatively lower capture rate in AF Art treatments on 1st day, although, the intake and assimilation of AFArt nauplii were clearly observed. Accordingly, growth and survival data were non-significant. The second was performed on larvae from 8-21 days after hatching (DAH), evaluating the enrichment impact of EG Art with four microalgae spp., Chlorella salina, Tetraselmis chuii, and a novel trail (Rhodomonas salina) which represented as (CEA, TEA& REA), respectively against Nannochloroposis oculata (NEA) as control concerning growth performance, pigmentation, metamorphosis and survival. Additionally, detection of unsaturated fatty acids grouping mainly omega3 ratios in various enriched Artemia was performed. Results revealed that the percentage of PUFA, HUFA and n-3 fatty acids were significantly higher (p < 0.01) in (REA) compared with (TEA) followed by (NEA) & (CEA), respectively. Otherwise, DHA/EPA and EPA/AA ratios were promoted in REA then NEA whereas no values for DHA/EPA were detected in both TEA & CEA treatments due to DHA absence. Larvae group C4 achieved maximum growth of 111.06 ± 0.2mg; on contrary (C2) attained the lowest results. In C4 group; metamorphosis took 9 days, while it extended to 10, 11, and 12 days in C1, C3, and C2, respectively. However, the onset pigmentation of larvae was surpassed in TEA followed by REA within 3-4 days from the beginning of the experiment shorter than NEA. Moreover, the C4 group achieved the highest survival of 80 ± 2.4%, while C2 attained the lowest records. This study authenticated the possibility of using AF-Art as the first feed to facilitate breeding intricacy as also suggested R. salina alga enrichment as a prime candidate for improving the Clownfish industry.
Keywords
Amphiprion bicinctus; Artemia Enrichments; Rhodomonas salina; Nannochloropsis oculata; Tetraselmis chuii; Chlorella salina
Statistics
... Knowing the first feeding requirements is a crucial factor influencing successful breeding in the majority of marine fish aquarium species (Koven et al., 1999;Rainuzzo et al.,1997;Rønnestad et al., 1999Rønnestad et al., , 2003. The urgent need for fast growing in economic species, such as A. bicinctus, is that the larval diet must match each energetics and nutritional needs. ...
Two experiments were performed in this investigation. The first was
established to compare the use of enriched rotifers (EROT) against
AF Artemia (AF Art) for substituting rotifer as start feeding for Clownfish
larvae and lasted 7 days. The observations showed a relatively lower capture
rate in AF Art treatments on 1
st
day, although, the intake and assimilation of
AFArt nauplii were clearly observed. Accordingly, growth and survival data
were non-significant. The second was performed on larvae from 8-21 days after
hatching (DAH), evaluating the enrichment impact of EG Art with four
microalgae spp., Chlorella salina, Tetraselmis chuii, and a novel trail
(Rhodomonas salina) which represented as (CEA, TEA& REA), respectively
against Nannochloroposis oculata (NEA) as control concerning growth
performance, pigmentation, metamorphosis and survival. Additionally,
detection of unsaturated fatty acids grouping mainly omega3 ratios in various
enriched Artemia was performed. Results revealed that the percentage of PUFA,
HUFA and n-3 fatty acids were significantly higher (p<0.01) in (REA)
compared with (TEA) followed by (NEA) & (CEA), respectively. Otherwise,
DHA/EPA and EPA/AA ratios were promoted in REA then NEA whereas no
values for DHA/EPA were detected in both TEA & CEA treatments due to
DHA absence. Larvae group C4 achieved maximum growth of 111.06 ± 0.2mg;
on contrary (C2) attained the lowest results. In C4 group; metamorphosis took 9
days, while it extended to 10, 11, and 12 days in C1, C3, and C2, respectively.
However, the onset pigmentation of larvae was surpassed in TEA followed by
REA within 3-4 days from the beginning of the experiment shorter than NEA.
Moreover, the C4 group achieved the highest survival of 80 ± 2.4%, while C2
attained the lowest records. This study authenticated the possibility of using AF�Art as the first feed to facilitate breeding intricacy as also suggested R.
salina alga enrichment as a prime candidate for improving the Clownfish
industry
... Compared to the eggs (stage B), the small degree of δ 15 N-enrichment in pre-released larvae (stages H-J) suggests a fast protein turnover in developing embryos, resulting in the excretion of lighter nitrogen and leading to 15 N-enrichment. Additionally, the selective use of some yolk reserves such as lipids and free amino acids would occur, which is a common feature in many developing fish embryos [91][92][93][94]. ...
The great pipefish Syngnathus acus is one of the most representative European syngnathids, being highly associated with seagrass and macroalgal beds. Surprisingly, the ecology of this large ovoviviparous marine fish has received scanty attention. The population inhabiting three sites on Cíes Archipelago (Atlantic Islands National Park, NW Spain) was monitored in 2017–2018 for spatial and temporal changes in abundances, reproduction traits, trophic niche occupancy, and dietary regimes across reproduction states, through an isotopic (δ
13C and δ15N) approach. Abundances were highly variable across seasons and sites, decreasing significantly from mid-autumn. The population consisted almost exclusively of large adults that migrate by the end of the breeding season, which extended from mid-spring to summer. Operational sex ratios suggest that the species is sex-role
reversed. S. acus is a secondary consumer (Trophic position = 3.36 ± 0.05), preferring amphipods but displaying annual and seasonal dietary plasticity. Mature fish were less selective than immatures
(especially females), with a higher preference for amphipods (36–68%) in the former. The second most preferred prey were carideans, copepods, or isopods, depending on the year and the reproduction
state. Overall, the wider trophic niches in females and immature specimens compared to males and mature fish would indicate a higher variability in both the use of prey resources and/or their origin.
The present study highlights the trophic plasticity and unique features of S. acus population in the Cíes Archipelago, especially regarding the outstanding size of the fish and the exceptional occurrence of breeders.
... Compared to eggs (stage B), the small δ 15 N-enrichment in pre-released larvae (stages H-J) suggests a fast protein turnover in developing embryos resulting in the excretion of lighter nitrogen and leading to a 15 Nenrichment. Besides, selective use of some yolk reserves such as lipids and free amino acids would occur, which is a common feature in many developing fish embryos [91][92][93][94]. ...
The great pipefish Syngnathus acus is one of the most representative European syngnathid, being highly associated with seagrass and macroalgal beds. Surprisingly, the ecology of this ovoviviparous marine fish has received scanty attention. The population inhabiting three sites on Cíes Archipelago (Atlantic Islands National Park, NW Spain) was monitored in 2017-2018 for spatial and temporal changes in abundances, reproduction traits, trophic niche occupancy and dietary regimes across reproduction states through an isotopic (δ13C and δ15N) approach. Abundances were highly variable across seasons and sites, decreasing significantly from mid-autumn. The population consisted almost exclusively of large adults that migrate by the end of the breeding season, which extended from mid-spring to summer. Operational sex ratios suggest that the species is sex-role reversed. S. acus is a secondary consumer (Trophic position= 3.36 ± 0.05) preferring amphipods but displaying annual and seasonal dietary plasticity. Mature fish were less selective than immatures (especially females) with a higher preference for amphipods (36-68%) in the former. The second most preferred prey were carideans, copepods or isopods, depending on the year and reproduction state. Overall, the wider trophic niches in females and immature specimens compared to males and mature fish would indicate a higher variability in both the use of prey resources and/or their origin. The present study highlights the trophic plasticity and unique features of S. acus population in Cíes Archipelago, especially regarding the outstanding size of the fish and the exceptional occurrence of breeders.
... Thus, the endogenous energy source in eggs is not defined by egg size alone. Some studies suggest that nutritional demands change during embryonic development and depend on broodstock management and physiological events [29][30][31]. Accordingly, further studies are needed to better understand the changes in organ development during embryogenesis. ...
Changes in nutritional constituents and enzyme activities were clarified in yellowfin tuna (YFT, Thunnus albacares) eggs during embryonic development, from eggs immediately after fertilization to hatching. The protein levels in the eggs gradually increased with development until the completion of hatching. In contrast, the triglyceride (TG) and free amino acid (FAA) levels in the eggs gradually declined with embryonic development until hatching was complete, although the energy composition of the FAAs was lower than that of the TGs throughout embryonic development. These results indicate that endogenous TGs are preferentially expended as an energy source during embryonic development. Overall, changes in the activities of aspartate aminotransferase, alanine aminotransferase, creatine kinase, and alkaline phosphatase showed similar patterns throughout development. First, the enzyme levels diminished; then, they remained at constant, low levels just before hatching, when they rapidly increased. This rapid increase was consistent with the protein content, suggesting that organ differentiation and functionalization were promoted during this period. These results will contribute to the establishment of mass-seeding production of YFT.
... Broodstock must be fed a good-quality diet for several months before spawning (Rainuzzo et al., 1997). In this feeding trial, dietary algae inclusion as a replacement of fish meal resulted in a significant increase in reproductive performance (total fry production) of guppy. ...
... The lipid and fatty acid composition of the breeders' diet have been identified as the main factor determining the successful reproduction and survival of the offspring. Some fish species will incorporate highly unsaturated fatty acids in the eggs, even during spawning; these HUFAS with 20 or more carbon atoms directly affect the maturation of fish and steroidogenesis through their metabolites 22,23 . ...
Sustainability in aquaculture is a necessity of the future, not only as the most promising means of supplying the protein that the world will require to feed its growing population but to offer needed conservation of the world’s ocean resources. The use of wild fish inputs in farm-raised fish outputs has been a primary concern of sustainability in aquaculture production. Herbivorous fish are more efficient converters of protein into fish flesh. Species of the genus Medialuna fish have been reported as a fast-growing, short-lived species. The native fish Acha ( Medialuna ancietae Chirichigno 1987) in the Northern part of Chile is an over-exploited fish that has been associated with aquatic vegetation as a food source. We studied the feeding habits and nutritional composition of M. ancietae. For this, we developed a reference collection of marine macroalga (epidermis and nutritional composition) observed in the diet of individuals of this species for the study of digestive material. More than 90% of the components found were marine macroalgae, indicating that M. ancietae is an herbivorous fish. Compared to non-herbivorous fish our results showed that most of the nutrients present in the Medialuna diet are found at much lower levels including n-3 long-chain polyunsaturated fatty acids (49.7%) and protein (13–60%). M. ancietae meat provides essential components of human nutrition with a significant protein content (18.99 ± 0.26%) and 268 ± 5.9 mg/100 g of the essential n-3 long-chain polyunsaturated fatty acids. Most fed aquaculture non-herbivorous species rely on wild-captured fish for these essential nutrients, while M. ancietae can obtain and concentrate them from potentially cultivable macroalgae. M. ancietae has potential for sustainable aquaculture production as a contribution to nutrition security and the re-stocking of wild populations.
... In this study, fish size in the range of 11 to 20 cm had relatively higher levels of PUFAs than fish in the categories of 1 to 10 cm, 21 to 30 cm, and 31 to 40 cm size classes. PUFAs play an important role in the gonadal maturation (Rainuzzo et al., 1997;Izquierdo et al., 2001;Sargent et al., 2002). Thus, the relatively high levels of PUFAs observed in the range of 11 to 20 cm might be related to the reproductive stage and size at maturity for this fish. ...
The objective of this study was to establish the fatty acid profile of Alestes baremoze, with a view of establishing its dietary fatty acid requirements. Fish samples from Lake Albert were categorized into four classes according to fork lengths (1–10 cm, 11–20 cm, 21–30 cm, and 31–40 cm), with each class comprising of six fish. In addition, eggs were collected from six sexually mature females. A total of 35 fatty acids were identified and categorized into saturated fatty acids (SFAs), monounsaturated acids (MUFAs), and polyunsaturated fatty acids (PUFAs). SFAs accounted for 5.07% to 37.05%, MUFAs and PUFAs constituted 20.65% to 53.78%, and 10.34% to 66.10% respectively, of total fatty acids in all studied fish size classes. The results from this study indicated that fatty acid composition in A. baremoze varied significantly with size classes. The findings may provide guidance on the fatty acid inclusions for diets formulated for this fish under culture conditions.
... As far as the polyunsaturated fatty acids (PUFA) are concerned, arachidonic acid (20:4n-6), eicosapentaenoic acid (20:5n-3), and docosahexaenoic acid (22:6n-3) were the most abundant PUFA in the muscle lipids of both species, which is followed by linoleic acid (18:2n-6). The importance of these fatty acids, especially of n-3 highly unsaturated fatty acids, in fish and crustacean nutrition is well known [46,47], while they are critical nutrients for human nutrition [48]. In crustaceans, it has been shown that 20:5n-3 and 22:6n-3 play significant roles in the reproduction process [49], as well as in molting and growth [50]. ...
The European spiny lobster is a species of great commercial value, yet a limited scientific knowledge exists on its biology, ecology, and physiology, especially for the stocks from east Mediterranean waters. The northern brown shrimp, a non-indigenous established species, is commercially exploited in regions of the Mediterranean Sea. Both species’ proximate composition and fatty acid profile were assessed for the first time in the Mediterranean region, exhibiting an overall significant statistical difference. Protein, fat, and energy contents were significantly higher in the northern brown shrimp, whereas moisture and ash contents were significantly higher in the European spiny lobster. The proximate composition for both species was well within the reported range for other lobster and prawn species in the Mediterranean Sea.
... Microalgae are a natural source of n-3 fatty acids, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are accumulated in the marine food chain (Reitan et al. , 1997Brown et al. 1997;Shah et al. 2018). The chemical composition of microalgae varies with species and classes, and the lipid content typically ranges from 10 to 60% of dry matter Brown et al. 1997;Chiu et al. 2009;Rodolfi et al. 2009;Doan et al. 2011;Wang et al. 2019). ...
Marine microalgae are a promising sustainable source of lipids, omega-3 fatty acids, and carbohydrates. Selected microalgae species belonging to the Bacillariophyceae, Haptophyceae, Eustigmatophyceae, and Prasinophyceae were characterised for cellular content of carbon and nitrogen, and for production yields of lipids, fatty acids, total carbohydrates, and β-glucans. Carbon and nitrogen content showed a hyperbolic decrease with increasing cell numbers for Chaetoceros calcitrans , C. muelleri , Skeletonema costatum , Tetraselmis sp., and Nannochloropsis oculata . Cultures of Pavlova lutheri and Tisochrysis lutea showed an increase in carbon content per cell, but a decrease in nitrogen content. The total lipid content of C. muelleri , C. calcitrans , N. oculata , and T. lutea increased with decreasing relative growth rate; however, the highest productivity of lipids was found in T. lutea grown at 40% of the maximum specific growth rate. The highest content of eicosapentaenoic acid was found in C. muelleri , C. calcitrans , and N. oculata , and the highest content of docosahexaenoic acid was found in T. lutea . The β-glucan fraction of the carbohydrates was highest in C. muelleri and C. calcitrans and was very low in N. oculata . Out of the species investigated, C. muelleri had the highest production yield of β-glucans, obtained when cultivated at a 40% relative growth rate.
Temperature modifies the reproductive success of fish, yet, in many species, we lack the information on its role in the early development. In this study, the effect of temperature on the relation between maternal traits (length, age, somatic condition, and muscle lipid and ovarian thyroid hormone concentrations), egg quality (fertilization success, development rate, mortality, and hatching success), and offspring traits (size-at-hatch, yolk sac size, and proportion of malformations) were studied in Baltic herring (Clupea harengus membras) in the northern Baltic Sea. The experiments were conducted at an ambient temperature of 7°C and at an elevated temperature of 14°C using 5 to 15 females and 3 replicates per female. The results indicate that elevated temperature may result in a faster developmental rate, a lower early-stage mortality and hatching success, smaller size-at-hatch, a larger yolk sac size and a higher amount of larval malformations when compared to an ambient temperature. The egg and offspring traits were also associated with the maternal traits, indicating especially that thyroid hormones play a mediating role in the physiological processes.
Bonefish are members of one of the oldest extant teleost superorders, Elopomorpha, which also includes eels, tarpons, and ladyfish. All share a common larval stage called the leptocephalus or “glass eel” stage. Though bonefish serve an important role in Caribbean ecosystems and fisheries, little is known about their life history and reproductive process. In order to observe and better describe bonefish spawning characteristics, wild bonefish (Albula goreensis) were collected off of Stuart, FL, USA. The group was transported to Harbor Branch Oceanographic Institute and acclimated to captive habitats where they underwent monthly hormonal manipulation to induce spawning. Spawning events occurred on October 4 and 6, 2020. For both spawns, eggs were collected in an egg collector and transferred to Kreisel tanks to hatch. Samples of eggs were collected prior to hatching to determine biometrics such as size, fertilization success, and hatching success. Leptocephalus larvae were collected daily for up to 3 days post-hatch, and biometric data was recorded for a subsample of larvae. Total fatty acids were extracted from egg and larvae samples and analyzed using GC–MS detection methods. Larvae samples showed a general decrease in polyunsaturated fatty acids (PUFAs) coinciding with growth after hatching, supporting the notion that PUFAs are utilized for growth and metabolic processes. This project is part of a multi-year effort to successfully spawn bonefish in captivity and can be utilized as a baseline in future studies intended to inform conservation methods for wild populations.
Saline-alkalinity is one of the important ecological parameter that has an impact function on the physiological metabolism, osmoregulation, survival, growth, development and distribution of teleost fish. Oreochromis mossambicus, a species of euryhaline that can withstand a wide variety of salinities, may be used as a research model animal in environmental studies. In order to detect the metabolism responses and mechanisms of different osmotic stresses tolerance in the gills of O. mossambicus, in present study, the metabolic responses of O. mossambicus subjected to salinity (25 g/L, S_S), alkalinity (4 g/L, A_S) and saline-alkalinity stress (salinity: 25 g/L, alkalinity: 4 g/L; SA_S) with the control environment (freshwater, C_S) were investigated by LC-MS/MS-based metabolomics. The metabolism results indicated that numerous metabolites were identified between the stress groups and the control group. In addition, under three osmotic stresses, the amino acid and carbohydrate metabolism, levels of amino acids, osmolytes and energy substances, such as L-lysine, arachidonic acid, docosahexaenoic acids, creatine and taurine, were significantly affected and changed in the metabolism of the gills of O. mossambicus. The metabolism data indicated that signal transduction and regulation pathways, including FoxO signaling pathway, mTOR signaling pathway and prolactin signaling pathway, were enriched in the gill during adaptation to high salinity, alkalinity and saline-alkalinity stress. The results of this study provide more comprehensive and reliable data for the osmotic pressure regulation mechanism and biological response of euryhaline teleost, and provide reliable scientific basis for the breeding and research of high salinity tolerance population, and further promote the development and utilization of saline-alkalinity water resources.
Temperature is a fundamental physical regulatory factor in the lives of fishes and this effect is expressed particularly strong in the control of all reproductive stages viz. gametogenesis and gamete maturation, ovulation/spermiation, spawning and early developmental stages and survival. An improvement in broodstock nutrition and feeding greatly improved not only egg and milt quality but also seed production. Thus, more attention has been paid to the level of different nutrients in broodstock diets under the changing climate condition. The fact that for the success of reproduction and finally to the vitality of progeny, maternal nutrition with well-balanced nutrients has high priority.KeywordsClimate changeBroodstockReproductionFeed
This datasheet on Live food covers Identity, Description, Further Information.
Lipid is one of the most important nutritional factors affecting growth and survival of larval fish. This study aims to determine optimum level of lipid in formulated microdiets for the 10-day old rockfish (Sebastes schlegeli) larvae. Five granulated microdiets (CL11, CL14, CL17, CL20, and CL23) containing various (11%, 14%, 17%, 20%, and 23%, respectively) levels of lipid were prepared, and their lipid levels were controlled by adding fish oil at the expense of dextrin. The effects of feeding rockfish larvae with these formulated microdiets were compared with two commercial microdiets (Belgium and Japan), and local crumble diet. At the end of the 29-day feeding trial, weight gain (%) and total length (mm) of larval fish fed the CL20 diet were significantly (P < 0.0001 for both) greater and longer than those of larval fish fed all other formulated (CL11, CL14, CL17, and CL23) microdiets, and crumble diet. The proximate composition of the whole-body fish, except for lipid content was not significantly (P > 0.05) affected by the experimental diets. Crude lipid content of the whole-body fish was relatively well reflected from lipid levels of the experimental diets. In conclusion, the greatest weight gain and longest total length were obtained in larval fish fed the CL20 diet among the experimentally formulated microdiets. The optimum lipid level in the experimentally formulated microdiet was estimated to be 17.3% for rockfish larvae based on the broken-line analysis.
The Florida pompano, Trachinotus carolinus, is a prime marine finfish candidate for commercial production in the United States (U.S.). Low salinity conditions (i.e., < 30 parts per thousand, ppt) can affect the early development of T. carolinus by increasing osmoregulatory stress. To address the knowledge gap regarding the impact of low salinity on Florida pompano health, we conducted an experiment to determine the optimal salinity for the culture of fingerlings. Larvae were reared in three salinities (10, 20, and 30 ppt) at local producers' farms and growth, fatty acid profiles, and transcriptome responses were quantified every three days after hatching (3, 6, 9, 12, 15, 18, and 24 days post hatch) and results were compared across salinities. Larvae reared at 10 ppt grew at a normal rate and the developmental stage had a greater impact than salinity on fatty acid composition and larval gene expression. Although there were few differentially expressed genes between salinities (n = 17), there was an upregulation of gene sets associated with ribosomes and oxidative phosphorylation and a downregulation of glycerophospholipid and carbon metabolism at lower salinities in comparison to higher salinities. In the early days of development, the fatty acids linoleic acid (LA), alpha linoleic acid (LNA), and 18:3 n-6 were proven to be important as potential energy fuels and precursors for long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis, which was supported by the whole transcriptomics analysis. The gene expression of fatty acid synthesis genes coincided with changes in the fatty acid levels suggesting the ability of Florida pompano larvae to biosynthesize LC-PUFAs from LA and LNA precursors. Overall, this study suggests that it is possible to raise Florida pompano larvae for 24 DPH under low salinity conditions as low as 10 ppt. However, it is important to run this study for a longer period to investigate the long-term effects of low salinity on larval health and development. Importantly, this research serves as a model study for future on-farm collaborations and helps build a bridge between scientists and farmers in aquaculture.
Compromised nutritional conditions associated with dietary transitions and feeding cessation in the wild and during fish aquaculture operations are common and can impact growth and survival. These effects are especially prevalent during early ontogenetic stages. We quantified phenotypic and GI tract microbial community responses with an emphasis on protease-producing bacteria of lake sturgeon (Acipenser fulvescens) larvae, a species of aquacultural and conservational importance. To quantify responses associated with experimental food transition and feeding cessation, we performed a 36-day feeding experiment using two treatments: control and diet transition. However, larvae in the diet transition treatment failed to undergo transition and ceased feeding. Larvae in the diet transition treatment exhibited lower growth (total length and body weight) and survival than control larvae. Treatment had a greater effect than ontogenetic changes on taxonomic composition and diversity of the GI tract microbial community. Proteobacteria dominated the GI tract microbial community of the diet transition larvae whereas Firmicutes dominated the GI tracts of control larvae. Most of the 98 identified protease-producing isolates in both treatments were from genera Pseudomonas and Aeromonas: taxonomic groups that include known fish pathogens. Overall, failing to transition diets affected responses in growth and GI tract microbiome composition and diversity, with the later dysbiosis being an indicator of morbidity and mortality in larval lake sturgeon. Thus, microbiological interrogations can characterize responses to dietary regimes. The results can inform fish culturalists and microbiologists of the importance of dietary practices consistent with the establishment and maintenance of healthy GI tract microbiota and optimal growth during early ontogeny.
In order to increase omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA) availability and to improve the design of rotifer's enrichment protocols for marine larvae production, the endogenous fatty acid (FA) metabolism of the marine rotifer, Brachionus plicatilis was determined. To this purpose, the in vivo ability of this species to incorporate, esterify into the different lipid classes and to elongate/desaturate unsaturated FAs was investigated. Rotifers were incubated in 75 cm² tissue culture flasks, at a density of 75,000 rotifers per incubation, for 4 h. Incubations (n = 4) were performed at 21 °C, with 0.3 μCi of [1-¹⁴C]FAs including C18 FAs (18:1n-9, OA; 18:2n-6, LA; 18:3n-3, ALA) and LC-PUFA (20:4n-6, ARA; 20:5n-3, EPA; 22:6n-3, DHA). The present study demonstrates that rotifers possess an active metabolism over dietary FAs, being this species able to produce LC-PUFA from its C18 FA precursors. Interestingly, the action of a Δ12 desaturase that converts OA to LA and of a Δ15 desaturase over LA to produce ALA, seems to be also present, in agreement with previously reported functional characterization of ωx desaturases genes in this species. However, a globally low transformation rate was obtained, in addition to a lower incorporation of DHA into rotifer tissues compared to the other incubated substrates. The aforementioned factors, together with a competitive esterification pattern of DHA, LA and ALA into phosphatidylcholine (PC) or of EPA and ARA into phosphatidylinositol (PI), may give rise to rotifers with inadequate essential FA ratios for marine larvae nutrition, if ignored or incorrectly handled in the lipid enrichment process of this live prey species.
This book resumes many years of research experience of the authors and their colleagues, as well as numerous European and Chinese experimental and field studies on the developmental biology and physiology of valuable commercial fish, the Black Sea kalkan (Scophthalmus maeoticus) and the Atlantic turbot (Scophthalmus maximus), closest relatives and, according to modern genetic research, presumably, one species. The history of formation of currently powerful industrial turbot aquaculture presented in this book is based on the analysis of numerous scientific and applied research on turbot mariculture and economic features of formation of its European, in particular, Spanish and Chinese clusters. Recommended for researchers – biologists and biotechnologists, university professors, students of biological and biotechnology specialties, specialists in aquaculture, fish farming, ecology, as well as for a wider range of readers, managers, economists and operators of aquaculture enterprises.
A 12-week feeding trial was designed to evaluate the potential of mealworm, Tenebrio molitor, meal (MW) as a locally available unconventional alternative source of protein for fish meal (FM) in a practical diet for juvenile black porgy. Five hundred twenty-five healthy fish (initial weight; 6.43 ± 0.00 g) were randomly distributed into five dietary groups in triplicate (35 fish per tank) and each group was hand-fed with one of the experimental diets containing graded level of a MW replacing 0%, 15%, 30%, 45%, and 60% of FM protein designated as MW0, MW15, MW30, MW45, and MW60, respectively. Although replacing 60% of dietary FM protein resulted in lower daily feed intake, juvenile porgies fed the highest level of dietary MW (MW60) still performed as well as control group (MW0). A significant negative trend was detected between fillet lipid content and increasing inclusion levels of MW in the diets. There was a notable reduction in the n-3 highly unsaturated fatty acids (HUFA) in the fillets of fish fed the MW containing diets, which became more prominent with greater levels of dietary FM replacement. Serum lysozyme activity improved with increasing inclusion levels of MW in the diet. Furthermore, expression of the antioxidant enzyme-related genes including glutathione peroxidase (GPx) and catalase (CAT) were markedly upregulated in liver of the fish fed diets replacing FM with MW when compared to fish fed the MW0 diet. Overall, the efficacy of MW as a promising alternative dietary protein source for juvenile black porgy has been proved not only in relation to weight gain and efficiency of feed utilization, but also the view point of health-promoting effects in fish.
Embryonic and early larval development and metabolism are fueled entirely by maternally derived nutritional resources (yolk and oil) before the onset of exogenous feeding. Composition of these maternally derived nutrients depends partly on maternal diet. Diet-egg relationships for fatty acids are well described for some species, but little is known about lipid transfer to eggs. To examine the effects of maternal diet on the egg composition, we fed adult red drum Sciaenops ocellatus six different diets, and measured lipid class and fatty acid composition of eggs they produced. Egg lipid class profiles remained relatively stable with only subtle differences in the concentrations of several lipid classes. Neutral lipid classes (wax ester/steryl ester (WE/SE), triglyceride (TG), sterol) varied more than polar lipid classes, with egg TG content being directly related to TG content of maternal diets. Dietary variations rapidly affected fatty acid composition of all major lipid classes in eggs (TG, WE/SE, phosphatidylcholine), with greater effects on neutral lipids than on the polar lipid. Results suggest a degree of maternal control over the provisioning of lipids as structural components (phospholipids) and energy substrates (neutral lipids), which may ensure proper development of larvae. But, egg fatty acid composition within lipid classes is more variable, and this may have consequences for larval survival and performance. This study also suggests that the pathways of maternal-offspring nutrient transfer are likely different for neutral and polar lipids.
The selection of the proper feed in combination with application of appropriate feed management strategies is the critical aspect of efficient aquaculture production. Matching feeding practices that account for nutrient density and physical characteristics of feed to provide the optimum daily supply of nutrients to optimize growth and health of the culture species is one of the most difficult aspects of aquaculture production to manage. There is no single set of feed management practices that cover the large number of farmed fish species, fish farming systems, and feed types. This chapter presents general feed management principles that will provide a basic knowledge base to use as a foundation for developing and applying science-based aquaculture feed management practices.
The lipid and fatty acid compositions of rotifers (Brachionus plicatilis) fed on yeast or on the unicellular prymnesiophyte Pavlova lutheri, an alga commonly used in Australian hatcheries, were compared by TLC-FID, GC and GC-MS. Significantly higher relative proportions of energy-rich triacylglycerol were present in the Pavlova-fed rotifers than in the yeast-fed animals, and total lipid content reached a maximum between 12 and 24 h. High incorporation of the essential fatty acids eicosapentaenoic acid (EPA; 20: 5ω3) and docosahexaenoic acid (DHA; 22:6ω3) occurred in the Pavlova-fed rotifers. EPA and DHA content was 11.6% of total fatty acids after 3 h of feeding and reached 20 and 23% after 24 and 48 h respectively. The proportion of essential fatty acids in rotifers fed Pavlova compares very favourably with data obtained by overseas workers using a variety of microalgae and dietary supplements. On the basis of fatty acid composition alone, these results confirm the suitability of P. lutheri as a feedstock for Australian mariculture operations.
The n−3 fatty acids and the lipid class requirement of larval Sparus aurata were studied by comparing patterns of conservation and loss of lipid levels and their content of selected fatty acid groups in starved (for 6 days) and feeding (fed 17 days on Isochrysis enriched rotifers) larvae.There was a marked decrease in the neutral fraction while the reduction in the polar fraction was more moderate in both feeding and starved larvae. In starved fish the pattern of fatty acid loss (percent decrease in μg/mg of dry weight larvae) in the total, neutral and polar fractions was expressed as n−6 >n−9 >n−3. However, the polar lipid in fed fish exhibited a reverse trend that can be described as n−3 >n−9 >n−6. Docosahexaenoic acid (22:6 n−3) was also observed to be more strongly conserved than eicosapentaenoic acid (20:5 n−3) during starvation but more drawn upon in feeding.The results suggest a larval biochemical strategy to conserve the important n−3 fatty acids during starvation. However, their loss during feeding implies that Isochrysis-enriched rotifers do not provide sufficient levels of these fatty acids for growing Sparus aurata larvae.
SUMMARY Gas-liqiiid chromatographic analyses of the Clz to CB saturated and unsaturated fatty acids of lipids from Pacific sardine ovaries, mesenteric fat, whole blood, and planktonic eggs are presented and compared. Lipids from planktonic eggs and ovaries, with ova in different stages of matura- tion, have strikingly similar and constant fatty acid compositions. Changes are shown to occur in the fatty acid pattern of mesenteric fat, blood, and ovarian lipids when sardines are fed an artificial diet rich in oleic and linoleic acids. Lipids from sardines fed chiefly on a natural crustacean diet were analyzed for comparison. In general, whole blood lipids have a fatty acid composition similar to the ovary; mesenteric fat differs from ovarian and blood lipide by having a lower content of linoleic acid. In the Pacific sardine, Sardinops caerulea Girard, the gonads increase greatly in weight and size prepara- tory to spawning. Each ripening egg contains a small (0.2 mm diameter) oil droplet. After the eggs ale spawned into sea water and during embryological development, the larvae consume the oil and the proteinaceous yolk. An active synthesis and turnover of organic constituents seem likely during ovarian deposition of this oil. Although the complex mixture of fatty acids in fish fats seems to reflect the composi- tion of the fat in the food eaten (l), fishes occasionally alter the fatty acid composition of their fat by virtue of their own metabolism (2). The purpose of this study was to investigate the changes occurring in the fatty acid composition of lipid during its deposition in the maturing sardine ovary. Because diet usually alters the fatty acid composition of fish lipids, an artificial diet was fed to sardines and its effect on mesenteric fat, blood, and ovarian lipids was examined.
Four emulsions differing in lipid class composition: triacylglycerols, ethyl esters, phospholipids and wax esters were used to enrich rotifers either through short-term (ST) enrichment (24 h) or through long-term (LT) enrichment (10 days). Higher lipid levels were obtained by using the ST enrichment method. This was particularly marked in the high triacylglycerol accumulation in rotifers enriched on the phospholipid-based emulsion. Ethyl esters were effectively assimilated and incorporated into triacylglycerol by rotifers in both the ST and LT techniques. A high docosaehexanoic/eicosapentaenoic acid (DHA/EPA) ratio was obtained in the LT technique using the ethyl ester-based emulsion. However, the other emulsion treatments gave higher or equal DHA/ EPA ratios using the ST technique. Absolute phospholipid levels were independent of both dietary lipid composition and enrichment method used, whereas triacylglycerol levels depended on these parameters. During starvation the level of phospholipid, in absolute terms, decreased slightly whereas the triacylglycerol fraction decreased considerably. Rotifers enriched on the wax ester-based emulsion using the LT technique exhibited higher levels of long-chain monoenes (i.e. 20:1 and 22:1 isomers) than when the ST technique was used. This suggests that hydrolysis of the wax esters and oxidation of the liberated fatty alcohols to fatty acids occurred when the LT technique was applied.
The effect of different lipid compositions of live feed on the survival, growth rate and pigmentation success of turbot larvae, Scophthalmus maximus (L.), was investigated. Rotifers, Brachionus plicatilis, together with the algae Tetraselmis sp., were administered until day 12, and Artemia was fed until day 27. The experimentally treated live feeds were enriched with four formulated emulsions, resulting in a gradient in the relative contents of Ω3 HUFA (highly unsaturated fatty acids) and in DHA (docosahexaenoic acid, 22:6 Ω3)/EPA (eicosapentaenoic acid, 20:5 Ω3) ratios in both the rotifers and Artemia.
There were no differences in larval growth rate, and only small differences in survival rate throughout the feeding experiment, probably because of satisfactory levels of Ω3 HUFA in the live feed to sustain growth and survival. A correlation was obtained between the percentage of completely pigmented 27 d old turbot and the DHA/EPA ratio in the total lipids of 12 d old larvae, which again was correlated with the corresponding ratio in the live feed used. The results suggest that normal pigmentation in turbot requires dietary DHA in the early larval feeding period, and that this requirement cannot be replaced by EPA.
Rotifer cultures of Brachionus plicatilis (SINTEF-strain, length 250 μm) rich in ω3 fatty acids were starved for > 5 days at variable temperature (0–18 °C). The net specific loss rate of rotifer numbers were 0.04 day−1 (range 0–0.08 day−1) at 5–18 °C, but reached values up to 0.25 day−1 at 0–3 °C. The loss rate was independent on culture density (range 40–1000 ind ml−1), but was to some extent dependent on the initial physiological state of the rotifers (i.e., egg ratio).
The loss rate of lipids was 0.02–0.05 day−1 below 10 °C, where the potential growth rate of the rotifer is low (0–0.09 day−1). The loss rate of lipids increased rapidly for higher temperatures where the rotifer can maintain positive growth, and reached 0.19 day−1 at 18 °C. The Q10 for the lipid loss rate versus temperature was higher than the Q10 for respiration found in other strains. This may suggest that other processes than respiration were involved in lipid catabolism. The content of ω3 fatty acids became reduced somewhat faster than the lipids (i.e. in particular 22:6 ω3), but the fatty acid per cent distribution remained remarkably unaffected by the temperature during starvation.
The results showed that rotifer cultures could be starved for up to 4 days at 5–8 °C without essential quantitative losses of lipids, ω3 fatty acids, and rotifers. The rotifers exhausted their endogenous lipids through reproduction (anabolism) and respiration (including enhanced locomotion) at higher temperatures. At lower temperatures, the mortality rate became very high.
Plaice (Pleuronectes platessa L.) were sampled during periods of growth and starvation, from the end of the yolk-sac stage through metamorphosis, for changes in water, triglyceride, carbohydrate, total nitrogen, total carbon, and ash. The percentage of water in larvae decreased continuously during development. During post-hatching growth (up to late Stage 2) nitrogen and carbohydrate were laid down faster than triglyceride. The pattern changed during later larval development. The early deposition of protein in preference to neutral fat suggests that conversion of food during growth, without simultaneously laying down fatty energy stores, may be advantageous to pelagic marine fish larvae. During starvation the percentage of water in plaice larvae increased. Triglyceride, carbohydrate, nitrogen and carbon (as a percentage of the dry body weight) decreased during starvation, but ash increased sharply. The continuous use of nitrogen during starvation may be a catabolic adaptation to the marine environment.
Fertilized Atlantic halibut (Hippoglossus hippoglossus L.) eggs in different developmental stages (Days 0 to 18) were sampled from plankton in North Norway in February 1986 and analysed for lipid classes and fatty acid content. In unfertilized ovulated eggs taken from ripe fish caught in 1983/1984, polar and neutral lipids comprised ca. 71 and 30% of the total lipids, respectively, decreasing and increasing to 67 and 33%, respectively, in Stage III (11 to 18 d old) fertilized eggs. Of the polar lipids, phosphatidylcholine decreased markedly from 62% in unfertilized ovulated eggs to ca. 40% in Stage I (0 to 3 d old) fertilized eggs, while phosphatidylethanolamine increased from ca. 7 to 33%. Triacylglycerols, the major neutral lipids, increased from ca. 13% in unfertilized ovulated eggs to 16% in Stage III fertilized eggs. The total lipid in Stage I fertilized eggs had relatively low levels of polyunsaturated fatty acids (PUFA), with (n-3) PUFA accounting for only ca. 25% of the total fatty acids. The (n-3) PUFA increased to ca. 40% of the total fatty acids in Stage III, while the (n-3): (n-6) ratio increased from 4.1 to 7.0.
In order to define the nutritional role of dietary phospholipids (PL) in larval fish, the PL classes and possible fatty acid combinations of phosphatidylcholine (PC) were investigated on the food organisms such as the micro-algae and rotifers Brachionus plicatilis, post-larval prawns (P-30) Penaeus japonicus, and larval fish. PC and phosphatidylethanolamine were the major PL classes in a marine Chlorella (CH), Tetraselmis (TS), rotifers cultured with either CH or TS, red sea bfeam (40-days old) Chrysophrys major, knife jaw (30 days-old) Oplegnathus fasciatus, Ayu (74-days old) Ptecoglossus altivelis, and prawn. The major PC in the larval fish and prawn were those having fatty acid combinations of C16C20 (mainly C16:0, C20:5ω3), C16C22 (mainly C16:0C22:6ω3), and C18C22 (mainly C18:0C22:6ω3 and/or C18:1ω9C22:6ω3). Because larval fish are incapable of de novo synthesis of ω3-and ω6-series of fatty acids and also possibly have a limited ability for the synthesis of some PC, a part of these PC occurring in the larval fish may be derived from food organisms such as the rotifers which contained PC with fatty acid combinations of C16C20 (mainly Cl6:0C20:5ω3).
The eight stages from fertilized egg to swim fry in the half beak Hemiramphus sajori were determined from changes of chemical composition during early development. 1. Wet weight of the egg was not very much changed before hatching and wet weight of the larva increased gradually until the end of yolk sac stage after hatching. 2. 0.238mg Protein was contained in the fertilized egg. There was more consumed after hatching than before hatching. 3. 73.2μg lipid was contained in the fertillzed egg. There was more consumed before hatching than after hatching. 4. Phospho-lipids were mainly consumed during developmental stages before hatching and neutral lipids were mainly used after hatching. 5. The amount of Carbohydrate contained was 33.8μg, 1.4%in wet material. This value was 7 times as much as much as the carbohydrate contents of rainbow trout and pacific sardine. However, there was no decrease in carbohydrats of the larva after hatching. Therefore carbohydrate contents were very important as an energy source for formation of the embryo in the before-eyed egg stage of the half beak. 6. The average calorie value of the fertilized egg was 4.726 kcal per gram dry wight This value was lower because the half beak egg contained more carbohydrate of the lower calorie/unit type than rainbow trout and pacific sardine. 7. The number of calories consumed per a day in the before-eyed egg stage was larger than in any other stages, that in the yolk sac stage was second.
A feeding experiment was conducted to ensure a relationship between quality of the feed and spawning or quality of eggs produced by feeding red sea bream broodstock with various diets with different nutritional quality. In the broodstock fed on the control white fish meal diet the average amount of eggs produced during the experimental period of about 2 months was 100.5 × l0⁴ eggs per fish, and 80.9% of these eggs were buoyant. In the group fed on the low-protein diet without supplemental phosphorus these values were lower than those in the control. The total amount of eggs produced by female fish given the EFA-deficient diet was comparable to that in the control, but proportion of buoyant eggs was the lowest, more than 75 % of eggs produced were deposited. Both values were highest in the group receiving the diet containing cuttlefish meal as a protein source, and moreover these eggs were mostly normal and showed a high rate of hatching, leading to a high productivity of viable larvae available as fish seed. The female broodstock receiving respectively the low-protein, the phosphorus-deficient and the EFA-deficient diets produced eggs significantly low in hatchability and in addition most of the hatched larvae showed deformity in the body and number or position of oil globules in egg yolk. Thus the present results have demonstrated that the reproduction of red sea bream is greatly affected by the nutritional quality of broodstock diets and that cuttlefish meal is superior to white fish meal as a protein source in diets for red sea bream broodstock. © 1984, The Japanese Society of Fisheries Science. All rights reserved.
It is generally accepted that the size of a marine fish year class is determined by the recruitment within the first year of life. The greatest proportion of the mortality occurs before the fish complete their larval stages. Many factors influence survival of young fishes: predation, genetic defects, perturbations of the physical environment, and starvation. The relative importance of each of these forms of mortality is not known, but it is thought that starvation may be a major source.
A study was conducted to examine the effects of low protein-high calory diets and the total deletion of trace elements from the mineral mixture in white fish meal diets on reproduction of rainbow trout and chemical components of eggs produced.
The results showed that eggs produced from the fish fed on the low protein diet with a high energy value gave good yields of eyes eggs with high hatchability compared to those fed on the control commercial diet. But, eggs from the fish fed on hte diet without supplement of trace elements were significantly low in both precentages of eyed eggs and hatchability. However, there was no marked difference in general compositions of eggs due to the difference of diets. The contents of Mn, Zn, and Fe in the bones and of Mn in eggs were significantly lower in the fish fed on the diet without supplement of trace elements than those in the fish receiving the commercial diets.
Thus, the results obtained in this study have demonstrated that the low protein-high calory diets supplemented with beef tallow has no adverse effects on reproduction of rainbow trout, and that a supplement of trace elements to fish meal diets is indispensable for reproduction of rainbow trout, although white fish meal contains various kinds of minerals.
This chapter discusses the yolk absorption in embryonic and larval fishes. The rate and efficiency of yolk absorption are influenced by a number of environmental factors, including temperature, light, oxygen concentration, and salinity. Fish eggs are not motile, and thus developing embryos are unable to actively exploit the most favorable environments available, at least until after hatching. In teleost eggs, the yolk syncytium together with overlaying mesoderm and ectoderm spreads to enclose the entire yolk mass. Endoderm does not follow the movement of the teleost blastodisc rim and, consequently, the yolk is not enclosed by an endodermal layer. Yolk platelets are mobilized more rapidly than the oil globule from the yolk mass, especially after hatching. The rate at which yolk reserves are depleted must be a function of the surface area of the absorptive layer and the metabolic activity of that layer.
This study was conducted to examine the effect of nutritional quality of diets given to broodstock on the ve ?? ge of spawning on reproduction of red sea bream, and to clarify whether or not egg quality is improved by enhancing incorpration of pigments from diets. The percentage of buoyant eggs was found to be improved by supplementing pigments such as β-carotene and canthaxanthin or astaxanthin to the diets given to broodstock on the eve of spawning. Feeding frozen raw krill shortly before spawning also resulted in marked improvement in both the tatal eggs produced and the percentage of buoyant eggs. On the other hand, in the group fed on the corn oil diet on the verge of spawning the proportion of buoyant eggs was markedly reduced from the original value by replacement of cuttlefish liver oil with corn oil. The rate of hatching was not improved by addition of pigments, but abnormality in number and position of oil globules was reduced and consequently the total number of normal larvae obtained became higher than in the original broodstock. These values were also effectively improved by feeding on frozen raw krill and the percentage of normal larvae obtained from buoyant eggs was elevated from the original value of 51.6% to 91.2%, whereas replacement of cuttlefish liver oil with corn oil in the given to broodstock even in a short period during spawning resulted in lowering of these values.
A feeding experiment was conducted to compare the EFA value between eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in juvenile red seabream, and to determine their requirements for both fatty acids by feeding them defatted fish meal diets containing different levels of EPA and/or DHA ranging from 0 to 1% in diet.
Juvenile red seabream fed a diet without supplemental EFA began to show a high mortality and poor appetite after one week feeding. The cumulative mortality of this group was 46% after 24 days. The growth and feed efficiency were effectively improved by elevating EPA or DHA levels to 1% or 0.5% in the diet, respectively. However, further elevation of the DHA level from 0.5 to 1% and addition of both EPA and DHA in diets at levels of 0.25 and 0.5% each did not result in further improvement of these parameters. The hepatosomatic index was high in the fish fed low levels of EPA or DHA and was reduced by elevating EPA levels to 1% in diets, although DHA was more effective than EPA.
Thus, the requirement of EPA and DHA was estimated to be around 1% and 0.5% in diet for juvenile red seabream, respectively. The EFA efficiency of DHA was also found to be about twice as high as that of EPA, and there was no additive effect of EPA and DHA on growth and feed efficiency.
A feeding experiment was conducted to investigate effects of quality of diets, given to rainbow trout broodstock for 3 months before their spawning, on the reproduction and egg quality by feeding various diets, with different levels of protein and lipid or a diet without supplemental essential fatty aid (EFA).
The growth rate and feed efficiency were high in the broodstock receiving the diet containing 36% protein and 18% lipid and in addition eyed rate and total hatch were also high in the eggs produced by the broodstock of this group. The growth and feed efficiency in the fish kept on the diet containing 28% protein becamen slow from around 60 days after feeding. Feeding the diet containing beef tallow as a part of energy source gave good results with regard to reproduction, comparable to those obtained in the broodstock fed on a commercial high protein diet. The EFA-deficient diet was found to result in low growth rates, eyed eggs and hatchability, and these results were also found to be effectively improved by supplementing ethyl linoleate to the diet, indicating importance of EFA for reproduction.
The results of this study have demonstrated that egg quality was greatly affected by the nutritional quality of diets given to rainbow trout broodstock for a short-period of 3 months before their spawning.
The fatty acid compositions of brain phosphoglycerides from a freshwater fish, the rainbow trout (Salmo gairdneri), and a marine fish, the cod (Gadus morhua), were determined and compared with those from a terrestrial mammal, the rat. Fish brain lipids were characterized by a higher degree of unsaturation encompassing increased percentages of (n-3)PUFA (22∶6 and 20∶5) and lower percentages of (n-6)PUFA (20∶4 and 22∶4). However the distribution of fatty acids and specific PUFA between different phosphoglycerides was essentially similar in rat and fish brain tissue. PE and PS contained the highest percentages of 22∶6(n-3), PI was characterized by higher 18∶0 and 20∶4(n-6)/20∶5(n-3), and PC had higher 16∶0 and the lowest percentage of PUFA in all species. A generally similar pattern was found in the fish retinal phosphoglycerides except that PC was also rich in 22∶6(n-3). Overall trout brain phosphoglycerides were slightly more unsaturated than the cod lipids but with lower (n-3)/(n-6) ratios whereas cod retinal lipids were more unsaturated than the trout retinal lipids.
Total lipid content, total lipid fatty acids, lipid classes and their fatty acid compositions were studied in eggs of gilthead sea bream from two different broodstocks.
The two broodstock diets used had the same total lipid content, but differed with respect to their fatty acid levels. The lipid class composition of eggs from different origins was not significantly different. The predominant polar lipids were phosphatidylcholine, phosphatidylethanolamine and sphingomyelin, and the main neutral lipid classes were cholesterol esters and triacylglycerols.
The fatty acid composition of total lipids and main lipid classes in the two groups of eggs showed marked differences, reflecting the influence of fatty acid levels in the broodstock diets.
The present study tested the effect of dietary lecithin and exogenous lipase on the incorporation of oleic acid in the tissue lipids of gilthead seabream larvae (Sparus aurata). Two of four microdiets were prepared by the addition of [14C]oleic acid as free fatty acid (FFA) to diets containing either 5% cuttlefish liver oil (CLO) or 5% soybean lecithin. Glycerol tri[1-14C]oleate was similarly incorporated in two other diets identical in lipid (4% cuttlefish liver oil, 1% soybean lecithin) and non-lipid composition but differed in that one contained a supplement of 0.05% porcine lipase. The effect of these diets was tested by following the incorporation of the label (dpm/mg larvae DBW) in the neutral and phospholipid fractions of seabream larvae at four different ages (21, 27, 32 and 45 days after hatching).
A significant (p<0.05) effect of dietary lecithin on the incorporation of labelled FFA in both larval neutral and phospholipid fractions was demonstrated at all ages. This was particularly pronounced during early development (day 21) where fish fed the lecithin supplement incorporated 6.75 times more label than the diet containing [14C]oleic acid in CLO. The dietary lecithin enhancing effect diminished with age but was still significant at day 45 (2.17 times more label). In addition, the label was considerably higher in the phospholipid fraction compared to the neutral lipid, reflecting the high demand for membrane synthesis during rapid growth. Lecithin fed larvae demonstrated a higher consumption rate and efficiency of incorporation than fish consuming the cuttlefish liver oil diet, suggesting an emulsifying function for dietary phospholipid.
In contrast, the supplementation with lipase showed a clear effect only in older fish where 45 day old larvae fed the lipase diet demonstrated a 3.42 times increase in radioactivity in their tissue lipids. This late lipase response may be the result of an insufficient level of dietary lecithin (M) and a short intestinal length being ineffective, in the early larval stages, in incorporating labelled free fatty acid from dietary glycerol tri[1-14C]oleate breakdown.
In five separate experiments, eggs from a single female goldfish were fertilized at 20°C. They were incubated at 22°C for 6 hours, after which some of the eggs were transferred to 13°C. When a defined post-hatch developmental stage was reached, lipid extracts were prepared from larvae, both with yolk sacs intact and after removal of the yolk sac by dissection. Other larvae were sampled at yolk exhaustion. Gas chromatographic analysis of fatty acid profiles revealed that larvae incorporated 16:0, 18:0, 20:4 (n-6) and 22:6 (n-3) into their tissues in proportions higher than those present in the eggs from which they were derived. At 22°C, these trends were particularly apparent at yolk exhaustion. At 13°C, proportions of polyunsaturated fatty acids in the bodies of newly hatched larvae were higher than those in the 22°C larval bodies. Monounsaturated fatty acids were preferentially depleted during development, especially in larvae from high quality eggs. No dependence of egg quality, as assessed by larval viability at 22°C, on total egg lipid mass or fatty acid composition was found. Larvae from the lowest quality eggs showed a reduced preference for incorporation of (n-3) polyunsaturated fatty acids into their tissues.
1.1. Two main forms of neutral lipid are available to fish in the natural environment, namely triacylglycerols and wax esters.2.2. There is evidence that triacylglycerols can be hydrolysed completely to free fatty acids and glycerol in the gastro-intestinal tract and absorbed as such. Fatty alcohols resulting from wax ester hydrolysis are oxidized to the corresponding acid and thereafter follow pathways of fatty acid metabolism.3.3. Polyunsaturated fatty acids in fish tissues are predominantly of the ω3 series.4.4. Fatty acids of the ω3 series have essential fatty acid activity for fish. Some species have the ability to convert linolenic acid (18:3ω3) rapidly to longer chain polyunsaturated acids (20:5ω3, 22:6ω3) that have full essential fatty acid activity. Other species lack this ability and the polyunsaturated ω3 acid must be supplied preformed in the diet for maximal growth and freedom from pathology.
The use of enrichment emulsions to increase the (n−3) HUFA content of rotifers before feeding to marine culture organisms has been shown to increase growth and survival. These emulsions require (n−3) HUFA-rich oils which are not always available. A technique for the low temperature separation of unsaturated from saturated fatty acids is described, which can be used to enrich oils otherwise poor in (n−3) HUFA. Capelin fish oil that underwent low temperature crystallization separation at −70°C for 8 h produced an enriched fraction containing 50% less saturated fatty acids and 50% more polyunsaturates (2–6 double bonds). Emulsions containing this enriched fraction were fed to rotifers and resulted in a three-fold increase in the polyunsaturates of the rotifers.
1.1. The roe lipids of Baltic herring, roach, perch, burbot and rainbow trout, and a commercially processed cod roe, were studied quantitatively by TLC-FID.2.2. Depending on the fish species, lipids comprise 2.4–9.2% of the roe weight. During the maturation of Baltic herring and rainbow trout there was an increase in the proportion of polar lipids.3.3. The major lipids in the mature roe of Baltic herring and roach were polar lipids (75–90%); of rainbow trout, polar lipids and triglycerides (95%); and of perch and burbot, wax and sterol esters (80–85%).4.4. Variations in the lipid compositions suggest that major differences relate to individual species and not to families and orders.
1.1. Fatty acid and lipid class composition were determined in larvae of four marine species: Atlantic halibut (Hippoglossus hippoglossus L.), plaice (Pleuronectes platessa), cod (Gadus morhua) and turbot (Scophthalmus maximus) at hatching and prior to first feeding.2.2. Total fatty acid content decreased in the four species with up to 50% reduction in one of the halibut groups. Docosahexanaoic acid (22:6 n-3) was especially utilized.3.3. Low lipid utilization was found in turbot in relation to the other three species.4.4. Water environmental temperature may explain some of the differences in the fatty acid utilization and the source of metabolic energy between cold water species (halibut, cod, and plaice) and temperate species (turbot), in the period from hatching to prior to first feeding.5.5. Relative amounts of neutral lipids and phospholipids were similar in plaice, cod and halibut, approximately 25% and 75% of total lipids, respectively, and were approximately constant during the yolk-sac stage. Neutral lipids were dominant for turbot at hatching, accounting for 53–55% of the total lipids, while phospholipids predominated prior to first feeding, being 56–59%.6.6. Phosphatidylcholine was catabolized in halibut, plaice and cod but not in turbot, while phosphatidylethanolamine tended to be synthesized in all four species.
Varying egg quality is one of the limiting factors for successful mass production of fish fry. It may also cause some of the variability in recruitment observed in many wild stocks, since poor egg quality may decrease the survival potential of the hatched larvae. In the literature, the term egg quality has been defined and used in various ways by different authors. Due to the limited knowledge in the field, it has been difficult to pinpoint valid quality criteria. The only definition of egg quality that has general validity is probably the egg's potential to produce viable fry. The egg's potential to produce viable fry is determined by several physical, genetic, and chemical parameters, as well as the initial physiological processes occurring in the egg. If one of the essential factors is lacking, or is incomplete, egg development will fail at some stage. Thus, egg quality should be regarded as determined when the egg has left the female fish and the fertilization process is complete. This definition is, however, of very little practical value, since fry viability obviously cannot be determined before the fry is produced. Good practical criteria for the determination of egg quality should be both possible to identify early in development, and be simple to use. The problems of egg quality have received increasing attention, in relation to cultivation as well as to the assessment of reproduction of wild fishes. This chapter discusses the possible criteria for the determination of quality of fish eggs.
Changes in the lipid class and fatty acid composition of developing eggs and unfed larvae of cod (Gadus morhua L.) were studied with the objective of determining probable requirements of cod larvae for dietary lipid. The eggs were collected on 24 March 1985 from holding tanks containing cod which had been caught off the northwest coast of Scotland. Phosphatidylcholine (PC) was the only lipid class to decline in absolute terms during embryogenesis. Catabolism of neutral lipid was initiated during the first week after hatching, and the rate of neutral lipid utilisation increased after the larvae had completely absorbed their yolk sacs. The quantity of triacylglycerol (TAG) remained constant during embryogenesis, but the percentage of 22:6(n-3) int TAG increased substantially during this period. It was calculated that ca. 33% of the 22:6(m-3) released during the process of PC catabolism was incorporated into TAG and sterol ester. The results suggest that PC, replete in appropriate essential fatty acids, should represent a major proportion of the lipid in artificial diets for fish and crustacean larvae.
Turbot and rainbow trout, which had previously received diets free of fat, were fed [1-14C] fatty acids. The distribution of radioactivity in the tissue fatty acids was examined 6 days later. In rainbow trout fed
[1-14C] 18∶3ω3, 70% of the radioactivity was present in 22∶6ω3 fatty acid. In contrast, turbot fed [1-14C] 18∶1ω9, 18∶2ω6, or 18∶3ω3 converted only small amounts of labeled fatty acids (3–15%) into fatty acids of longer chain
length. The major product of the limited modification found in turbot was the dietary acid elongated by 2 carbon atoms.
Eggs and larvae of the winter flounder Pseudopleuronectes americanus Walbaum were hatched and raised in the laboratory under controlled conditions. Biochemical composition was measured during development and found to be similar to that of other species: 65 to 80 percent protein, 15 to 30 percent fat, and 0 to 5 percent carbohydrate. Ash content was 7 to 10 percent of dry weight. The chorion comprised more than half of the weight of an egg and the data suggested that it was possibly a source of nutrition to the developing embryo. The sequence of utilization appeared to be carbohydrate and then protein to hatching, lipid, mixed lipid and protein, the predominantly protein until feeding began. Carbohydrate was accumulated at first feeding and depleted when growth began. Protein and lipid were deposited in approximately constant proportions. Respiration rates of eggs were low, 0.002–0.015 l O2 egg-1 h-1, but rose gradually from fertilization to hatching. Respiration rates of early larvae were from two to eight times that of eggs (0.033–0.131 l O2 larva-1 h-1). Variation in larval respiration rates indicated a three-fold difference in rate according to level of activity. Eggs excreted ammonia at an increasing rate from fertilization to hatching. Larvae excreted ammonia, primary amines, and other unidentified organic nitrogenous substances. Rates of excretion and proportions of excretory products varied with stage of development. Primary amine excretion was variable and a major component in early stages. Ammonia-N excreted was two to 20 times primary amine N excreted. Unidentified substances were the predominant form of N excretion during early feeding. Ammonia accounted for most of the N excreted in older larvae. Early specific growth rates were 2.1 and 5.5%. Net caloric conversion and net and gross nitrogen efficiencies were low in first feeding larvae compared to adult fishes (32.2, 27.7, and 10.7% respectively).
The molecular species composition of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) from
white muscle, liver, retina and brain of cod (Gadus morhua) were determined by high-performance liquid chromatography of the respective 1,2-diacylglycerol 3,5-dinitrobenzoyl derivatives.
A minimum of 69 diacyl species was identified. In muscle and liver saturated fatty acid/polyunsaturated fatty acid (PUFA)
and monounsaturated fatty acid/PUFA molecular species were predominant, particularly 16∶0/20∶5 and 16∶0/22∶6 in PC, 16∶0/22∶6
and 18∶1/22∶6 in PE and 18∶0/22∶6 and 18∶1/22∶6 in PS. Didocosahexaenoyl species were major components of PC, PE and PS from
retina, comprising 29.3, 71.8 and 59.7% of the respective totals. Didocosahexaenoyl species were also abundant in PE and PS
from brain, accounting for 13.8 and 24.0% of the totals, respectively. DiPUFA species were important in muscle, totalling
21.2% in PC and 38.3% in PE. PC from all tissues had the largest amounts of species containing only saturated or monounsaturated
fatty acids, accounting for 59.8% of PC from brain, including 12.8% of 18∶1/24∶1 plus 24∶1/18∶1.
In the retina of herring (Clupea harengus L.), rods are recruited from about 8 wk after hatching, and from this time there is a linear relationship between the number
of rods in the photoreceptor cell population and the content of di22∶6n−3 molecular species of phospholipids. Juvenile herring
were reared from four weeks' post-hatching for 15 wk on eitherArtemia nauplii deficient in 22∶6n−3 or on enrichedArtemia nauplii containing 4.3% 22∶6n−3. The visual performance of the fish was then determined at three light intensities (0.01,
0.1, and 1.0 lux) by observing their frequency of striking at liveArtemia nauplii using infrared video recording. Herring reared on the diet containing no 22∶6n−3 were less active predators, especially
at the lowest light intensity where very few strikes were observed. The eyes of these fish contained greatly reduced levels
of di22∶6n−3 molecular species of total phospholipid, 2.1% vs. 12.0% in fish supplemented with 22∶6n−3. The contribution of
saturated and monounsaturated fatty acids in the molecular species of phosphatidylethanolamine (PE), phosphatidylserine (PS),
and phosphatidylcholine (PC) was virtually unchanged, while 20∶5n−3 and 22∶5n−3 largely replaced 22∶6n−3. There was an almost
complete disappearance of di22∶6n−3 PC, while the amounts of di22∶6n−3 PE and PS fell by 18.1 and 20.6% to 2.7 and 7.6%, respectively.
The dipolyunsaturated molecular species di20∶5n−3, 20∶5n−3/22∶5n−3, and di22∶5n−3 made up a substantial part of the deficit.
We conclude that a dietary deficiency of 22∶6n−3 during the period early in rod development impairs visual performance such
that the fish can no longer feed at low light intensities.
The changes in the lipid class and the fatty acid compositions of total lipids and individual glycerophospholipids which occur
in brain during development of juvenile turbot (Scophthalmus maximus L.) were investigated. Fish were sampled during a 10-week period immediately following weaning from a live feed to a pellet
diet. During this period, brain dry weight increased over 6-fold. The percentages of protein, cholesterol and galactolipids
increased in brain during development, presumably reflecting increased membrane maturation and myelination processes. The
percentages of docosahexaenoic acid (DHA; 22∶6n−3) were low at the beginning of the study period. However, DHA specifically
accumulated in juvenile turbot brain during development. The percentages of DHA increased in total lipid, total diradyl glycerophosphocholine
(GPC), total diradyl glycerophosphoethanolamine (GPE), phosphatidylserine (PS) and phosphatidylinositol (PI) reaching 26.1%,
25.8%, 40.8%, 47.1% and 17.9% of the total fatty acids, respectively, by the end of the 10-week period. The percentages of
other n−3 polyunsaturated fatty acids (PUFA) and n−6 PUFA generally decreased during this period, as did that of monoenes;
the percentages of saturated fatty acids remained relatively constant. Non-linear regression analysis showed that the increase
in DHA in total lipid, GPC, GPE and PS fitted 1st order rate kinetics (plus offset) allowing maximum values for the percentages
of DHA in each lipid class to be estimated.
1.1. The influence of hypo- and hypersalinity on the content of total proteins, lipids, carbohydrates, glycogen, free amino acids, protein amino acids, lipid class composition and fatty acids of total, polar and neutral lipids in Brachionus plicatilis has been examined.2.2. The protein, carbohydrate and glycogen content decreased with a simultaneous increase in the free amino acid content on an increase in salinity from 0.5 to 28%.. Salinity exerts the most appreciable effect on the content of such free amino acids as glycine, alanine, proline, arginine and glutamic acids. Alterations in the protein amino acid content were not observed.3.3. At salinities of less than 17%. and more than 17%., the lipid content decreased. Proportionally this effect was larger at high salinities.4.4. Lipid class composition was invariable in the range of salinity from 0.5 to 17%.. With a rise of salinity from 17 to 28%. the portion of phospholipids increased while that of triacylglycerols, sterol and wax esters decreased.5.5. An increase in the proportion of saturated acids and decrease of polyunsaturated acids with increased salinity were characteristic for the fatty acid composition of polar and neutral lipids. This was most perceptible in the range between 0.5 and 4%..6.6. The possible mechanisms of biochemical adaptation of the rotifer B. plicatilis are discussed.
Fatty acid and lipid class compositions were determined in eggs and larvae of turbot (Scophthalmus maximus L.). The larvae were fed on rotifers and Anemia fed on various lipid emulsions. Starving larvae were also studied. The lipid class compositions of the emulsions affect the fatty acid composition of the rotifers. Ethyl ester-based emulsion exhibited the highest assimilation by the rotifers and Artemia and were possibly incorporated in their triacylglycerol fraction. During larval starvation docosahexaenoic acid and arachidonic acid levels tended to be conserved whereas eicosapentaenoic acid was highly reduced. Moreover, the relative proportion of phosphatidylethanolamine increased whereas that of phosphatidylcholine decreased in starved larvae. Increasing the n-3 highly unsaturated fatty acid levels in rotifers and Artemia did not influence the survival and growth of the turbot larvae. A positive correlation was found between pigmentation success and the ratios of docosahexaenoic/ eicosapentaenoic acids in the total and polar lipid fractions of the turbot larvae. Furthermore, the amounts of these polyunsaturated fatty acids in the phosphatidylethanolamine fraction of the larvae are suggested to be of particular importance in turbot pigmentation.
Feeding incidence, survival and growth rates of Atlantic halibut larvae (Hippoglossus hippoglossus L.) were compared during first feeding in a suspension of natural phytoplankton (green water) vs. in filtered (clear) water. The larvae were fed nonenriched Artemia instar II. Feeding incidence at day 3 was 47% in green water and 0% in clear water. Both growth and survival were higher in green water compared to clear water. From a total of 2250 halibut larvae in the green water tanks, 684 survived to the end of the experiment (day 21). The corresponding number for the clear water tanks was 57 out of 4500. The results did not indicate direct or indirect nutritional effects of the phytoplankton, and no improved performance could be related to the quality of Artemia. Other aspects of green water, such as turbidity and effects on the light regime, are discussed in relation to perceptive distance and behaviour of fish larvae.
The mass production of zooplankton, in particular the rotifer, Brachionus plicatilis, and the brine shrimp, Artemia salina, is considered to be of vital importance for the rearing of larval fish (up to 30–50 mm total body length) in Japan. Data on the proximal, mineral, protein and essential fatty acid (EFA) contents of live food organisms are reviewed: the EFA content chiefly determines the dietary value for fish larvae. The EFA content of rotifers supplied with yeast during the culture period was less favourable for larval fish growth than that of rotifers given marine Chlorella. The nutritional value of yeast-fed rotifers may be improved either by the use of the recently developed ω-yeast (indirect method) or by feeding with a mixture of homogenized lipids and baker's yeast (direct method). Artemia could be classified into two types, marine — containing a high content of 20:5ω3 (an EFA for marine fish), and freshwater — containing a high content of 18:3ω3 (an EFA for freshwater fish). The fish mortalities sometimes encountered with Artemia may be related to this difference. Either type may be used for freshwater fish larval nutrition. For marine fish, the marine Artemia type is adequate but the freshwater type should be fed together with marine copepods or should be enriched by feeding on lipids with high ω3 HUFA contents.
The objective of this study was to determine the relative essential fatty acid (EFA) growth-promoting activities of pure arachidonic (AA, 20:4n−6) and docosahexaenoic (DHA, 22:6n−3) acids and various concentrations of these two acids in the diet of juvenile turbot (Scophthalmus maximus). Casein-based, semi-purified diets containing 15% fish oil or 14% hydrogenated coconut oil/oleic acid (1:1) supplemented with 1% 20:4n−6, 1% 22:6n−3 or 1% of various combinations of these two acids were fed to duplicate groups of 26 juvenile turbot for 11 weeks. In this trial, feeding the diet containing 20:4n−6 as the only highly unsaturated fatty acid (HUFA) resulted in higher growth and survival than any of the mixtures of the two fatty acids or 22:6n−3 alone. The diet containing 22:6n−3 as the sole HUFA resulted in the lowest growth and survival of all dietary treatments. The control diet with 15% fish oil resulted in a greater growth rate than any of the pure HUFA-supplemented diets. There was a significant effect of dietary lipid on the somatic index of the brain but not heart, kidney or liver. The percentage of lipid in the liver, but not of heart, brain, eyes, gills or kidney, was influenced by dietary lipid, with the highest percentage in fish supplemented with DHA alone. After 11 weeks, the 20:4n−6 and 22:6n−3 levels in whole-body total lipids were strongly influenced by the content of these fatty acids in the diets. The relative effect of dietary levels of these two fatty acids on their content in fish lipids varied considerably among the various organs and tissues of the fish that were analyzed. Brain and eye lipids were generally highest in 22:6n−3 while gill and kidney lipids were consistently higher in 20:4n−6 than the other organs analyzed. The effect of dietary 20:4n−6 on the content of that HUFA in organ lipid was greatest in gill and liver. The greatest impact of dietary 22:6n−3 level on content of that acid in organ lipid was seen in gill and kidney. There were also significant effects of dietary HUFA content on organ lipid levels of saturated, mono-unsaturated fatty acids and other members of the n−3 and n−6 PUFA, and HUFA series. The present study suggests that the EFA growth-promoting activity of arachidonic acid provides strong support for the contention that dietary 20:4n−6 is essential for juvenile turbot.
Two Artemia species (Artemia franciscana, GSL strain and a population from Artemia sinica, ARC No. 1188) were enriched with two different emulsions containing high levels of docosahexaenoic acid (DHA) (23 and 44% of total fatty acids, respectively) in filtered seawater (30 ppt) at 28 °C. After enrichment nauplii were starved for 72 h at three different temperatures (6.1, 12.2 and 22 °C). Following enrichment the DHA content and ratio reached a maximum 41.2 and 42.8 mg g−1 dry weight and 1.88 and 2.09 in A. franciscana and A. sinica, respectively. During starvation at 12.2 °C the DHA content in A. franciscana decreased steadily throughout the starvation period towards 1.11–2.89 mg g−1 dry weight ( ratio of 0.4) after 72 h, whereas in A. sinica the DHA content was > 20 mg g−1 dry weight ( ratio of 1.7–2). A quantitative reduction of DHA in A. sinica was observed only during the first 24 h of the starvation period. The degradation rate of DHA in A. franciscana increased with rising temperature (22 °C) and decreased at the lowest temperature (6.1 °C). This was not the case for A. sinica, during starvation at different temperatures the DHA level in A. sinica remained at a relatively high and constant level.
Cultures of the rotifer Brachionus plicatilis (200 ind./ml, 0.5 μg dry weight/ind.) pre-fed on yeast and capelin oil (10:1 w/w) were given different enriched diets and harvested after 24 h. The fatty acid composition of the rotifers was affected by that of the feed. The highest level of n−3 highly unsaturated fatty acids (HUFA) 38%) and 22:6 n−3 (19%) was obtained after enrichment of the rotifers fed with squid meal. A positive relation was found between the n−3 HUFA in the enrichment diet and that of the rotifers (P < 0.05, t-test). The cultivation feed of the rotifers may nevertheless be more important for the n−3 HUFA level than the enrichment feed. Starvation for 49 h did not change the fatty acid composition of the rotifers.