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Mineral Requirements in Fish—II Magnesium Requirement of Carp
Abstract
Magnesium deficiency in carp was found to produce a loss of appetite, poor growth, high mortality, sluggishness and convulsions. The minimal requirement of young carp for magnesium was 0.04 to 0.05% of a dry diet or 12 to 15 mg per kg body weight per day under the experimental conditions. The magnesium content of vertebrae from carp fed diets containing low magnesium decreased significantly while the calcium content increased slightly. Thus, the values for Ca/Mg of the vertebrae were changed by the dietary magnesium level.
... For marine species, dietary Mg supplementation may not be necessary because Mg requirements can be met by uptake from seawater, where Mg concentrations are high (Sakamoto and Yone 1979;Ye et al. 2010;Liang et al. 2015). In contrast, if the concentration of Mg in freshwater is low (1-4 mg kg −1 ), its uptake from the environment is considered insufficient to satisfy metabolic requirements (Lall 2002), and dietary requirements of Mg have been reported for several species of freshwater fish (Ogino and Chiou 1976;Gatlin et al. 1982;Shim and Ng 1988;Reigh et al. 1991;Han et al. 2012;Liang et al. 2011;Mohammad and Khan 2018). ...
... mg kg −1 diet Mg) were used to estimate the dietary Mg requirement of grass carp. This value is similar to that reported for other fish from 326 to 745 mg kg −1 diet (Ogino and Chiou 1976;Ogino et al. 1978;Knox et al. 1981;Shim and Ng 1988;Reigh et al. 1991;El-Mowafi and Maage 1998;Duan et al., 2012). ...
... Reigh et al. (1991) reported a positive response to 30-650 mg kg −1 diet Mg supplementation of blue tilapia (Oreochromis aureus) fed casein-based diets in terms of their growth, feed, and protein efficiency. A lack of Mg in the feed can dull appetite, slow growth, increase mortality, and significantly decrease the production performance in aquatic animals (Ogino and Chiou 1976;Cowey 1976;Cowey et al. 1976;Cowey et al. 1977;Knox et al. 1981;Gatlin et al. 1982;Shim and Ng 1988;Shearer 1989;Reigh et al. 1991;Wei et al. 2017;Mohammad and Khan 2018). Not all fish respond well in terms of growth to dietary Mg, such as Atlantic salmon (Salmo salar L.) (El-Mowafi and Maage 1998), tilapia (Oreochromis mossambicus (Peters)) (Velden et al. 1991), grass carp (Ctenopharyngodon Values represent means ± SD, n = 3. Means in the same column with different superscript letters are significantly different (P< 0.05) ‡ U activity unit of enzyme Aquaculture International idella) (Wang et al., 2011), and gibel carp ). ...
Sturgeons are an economically important freshwater aquacultural fish in China and elsewhere. Research was conducted to study the magnesium requirement of juvenile hybrid sturgeon ( Acipenser schrenckii ♀ × Acipenser baerii ♂) based on mineral composition, proximate chemical analysis, antioxidant enzyme levels, and growth metrics. Different levels of magnesium supplements (43.2, 157.3, 326.5, 549.6, 743.9, 938.4, and 1118.2 mg kg ⁻¹ ) were fed to juvenile sturgeon for 8 weeks. Five hundred twenty-five juvenile hybrid sturgeons (an average initial body weight of 7.65 g) were randomly divided into 7 groups with 3 replicates each (25 fish per replicate, tanks of 100×50×50 cm, dissolved oxygen ≥ 5.0 mg L ⁻¹ , 12 light:12 dark) and fed 4 times per day with the experimental diets containing 40.78% crude protein and 10.03% crude fat. The body tissues and blood of fish were then sampled and analyzed. Growth performance was not significantly different between treatments ( P> 0.05). The optimal dietary magnesium requirement for hybrid sturgeon was estimated to be 355.16, 573.6, or 584.6 mg kg ⁻¹ dietary magnesium based on whole-body Mg retention, the whole-body or vertebrae magnesium content versus dietary magnesium levels. The whole-body calcium to phosphorus ratio of the 43.2 and 326.5 mg kg ⁻¹ groups was significantly higher than that of the 938.4 mg kg ⁻¹ group ( P < 0.05). A dietary magnesium concentration of 350–700 mg kg ⁻¹ improved the antioxidant capacity by decreasing the serum malondialdehyde and enhancing serum superoxide dismutase, glutathione peroxidase, and catalase activities.
... The dietary requirements of rainbow trout (Cowey et al. 1977;Ogino et al. 1978;Knox et al. 1981), carp, Cyprinius carpio L. (Ogino & Chiou 1976), channel catfish, Ictalurus punctatus (Raf.), fingerlings (Gatlin et al. 1982), eel, Anguilla japonica T. & S. (Nose & Arai 1979), guppy, Poecilia reticulata Peters (Shim & Ng 1988) and tilapia, Oreochromis niloticus (L.) (Dabrowska et al. 1989;Reigh et al. 1991) have been estimated in fresh water, and range from 400 to 800 mg kg -1 dry diet. Shearer (1989) reported a Mg requirement for rainbow trout of 1300-1400 mg kg -1 diet based on dose-response data of body weight and the whole-body Mg concentration of fish fed a caseinbased diet. ...
... However, the basal diet contained less Mg than the requirement reported for those fish species where the Mg requirement has been studied (Ogino & Chiou 1976;Cowey et al. 1977;Ogino et al. 1978;Nose & Arai 1979;Knox et al. 1981;Gatlin et al. 1982;Shim & Ng 1988;Dabrowska et al. 1989;Shearer 1989;Reigh et al. 1991). ...
... Mg supplementation level had no significant effect on feed efficiency in this experiment (Table 2). Poor growth and reduced feed efficiency were observed in several studies of fish fed Mgdeficient diets (Ogino & Chiou 1976;Cowey et al. 1977;Ogino et al. 1978;Gatlin et al. 1982;Shim & Ng 1988;Shearer 1989;Reigh et al. 1991). On the other hand, Dabrowska et al. (1989) found that dietary Mg levels ranging from 60 to 3360 mg kg -1 had no effect on final mean weight or weight gain of Nile tilapia (O. ...
... Magnesium deficiency symptoms have also been identified for a number of fish species; these include anorexia, sluggishness, reduced growth, reduced bone magnesium concentrations and high mortality. Although fish bone contains a relatively small amount of magnesium, it is a primary site of magnesium exchange, and changes in bone magnesium concentrations have been used to provide an index of body magnesium status (Ogino and Chiou 1976;Ogino et al. 1978;Knox et al. 198 1 ;Gatlin et al. 1982). Scale magnesium con-centrations have also been used as an index of dietary mineral adequacy in studies of the calcium and phosphorus requirements (Robinson et al. 1984(Robinson et al. , 1987 and zinc requirement (McClain and Gatlin 1988) of Oreochromis aureus. ...
... As a result, the magnesium requirements of most fishes are satisfied principally through the diet. Quantitative dietary magnesium requirements of carp Cyprinus carpio, rainbow trout Salmo gairdneri and channel catfish Zctalurus punctatus range from 0.04 to 0.05% of diet dry weight (Ogino and Chiou 1976;Ogino et al. 1978;Knox et al. 1981;Gatlin et al. 1982). These requirements are similar to the magnesium requirements of some domestic mammals and birds (Kunkel and Pearson 1948;Van Reen and Pearson 1953;Mayo In magnesium supplemented diets a portion of cellulose was replaced with M@04 (20.2% Mg) to provide graded levels of elemental magnesium. ...
... It is apparent from the lower (P < 0.05) levels of magnesium in scale and bone of tilapia fed 0.003 to 0.023% magnesium, that absorption of magnesium from the water was not sufficient to maintain optimum scale and bone mineralization in fish fed less than 0.023% magnesium. Ogino and Chiou (1976) reported that common carp (2.8 g body weight) raised in water containing 3.5 mg Mg/L were unable to absorb enough magnesium from the environment to prevent deficiency symptoms when they were fed a magnesium deficient (0.005% Mg) diet. Conspicuous magnesium deficiency signs developed in these fish after two weeks of treatment. ...
Juvenile blue tilapia Oreochrornis aureus (mean weight 0.5 ± 0.05 g) were stocked into 38 liter glass aquaria receiving Row-through well water containing 0.1 mg magnesium/L and fed semipurified, casein-based diets containing graded levels of magnesium (0.003, 0.008, 0.023, 0.037, 0.050 and 0.065% magnesium, dry weight). Magnesium supplements were provided as anhydrous magnesium sulfate (MgSO4). No treatment-related mortalities occurred and no visible magnesium deficiency symptoms were observed in any treatment group during the 18 week experimental period. Magnesium concentrations in scale and bone of tilapia fed diets containing 0.023 to 0.065% magnesium were greater (P < 0.05) than in fish fed diets containing 0.003 to 0.008%. Scale and bone magnesium concentrations did not differ (P > 0.05) among fish that received dietary magnesium levels of 0.023% or greater. The magnesium content of muscle was higher (P < 0.05) in fish fed 0.037 to 0.065% magnesium than in those fed 0.003 to 0.008% magnesium. Muscle magnesium concentrations did not differ (P > 0.05) among fish that received 0.037% or more dietary magnesium. Adequate weight gain and superior feed efficiency occurred in fish fed 0.05 to 0.065% magnesium. Results indicated that diets for O. aureus should contain at least 0.05% magnesium (500 mg Mg/kg dry diet) for optimum growth and normal tissue mineralization.
... The quantitative dietary magnesium requirements for freshwater fish species such as common carp (Cyprinus carpio, Ogino and Chiou, 1976;Dabrowska et al., 1991), rainbow trout (Salmo gairdneri, Ogino et al., 1978;Knox et al., 1981;Shearer, 1989), channel catfish (Ictalurus punctatus, Gatlin III et al., 1982), guppy (Poecilia reticulate, Shim and Ng, 1988), Nile tilapia (O. niloticus, Dabrowska et al., 1989), blue tilapia (O. ...
... Weight gain, feed conversion ratio, protein efficiency ratio and protein gain of fingerling L. rohita fed varying levels of magnesium significantly improved up to 0.46 g kg −1 of diet (D 3 ) indicating the requirement of dietary magnesium of the fish under study to be 0.46 g kg −1 diet. However, broken-line regression analysis of LWG, SGR and PG against different dietary magnesium levels indicated the optimal magnesium requirement of fingerling L. rohita at 0.44, 0.44 and 0.45 g kg −1 diet, respectively, which is similar to the requirements reported for other fish species such as common carp (0.40-0.50 g kg −1 diet, Ogino and Chiou, 1976), eel (0.40 g kg −1 diet, Nose and Arai, 1979), rainbow trout (0.50 g kg −1 diet, Knox et al., 1981), channel catfish (0.40 g kg −1 diet, Gatlin III et al., 1982), guppy (0.54 g kg −1 diet, Shim and Ng, 1988), blue tilapia (0.50 g kg −1 diet, Reigh et al., 1991) but higher than that reported for Atlantic salmon (0.33 g kg −1 diet, El-Mowafi and Maage, 1998), hybrid tilapia (0.20 g kg −1 diet, Lin et al., 2013) and lower than that of rainbow trout (0.60-0.70 g kg −1 diet, Ogino et al., 1978; 1.30-1.40 g kg −1 diet, Shearer, 1989), Nile tilapia (0.60 g kg −1 diet, Dabrowska et al., 1989), common carp (0.60 g kg −1 diet, Dabrowska et al., 1991), grass carp (0.71 g kg −1 diet, Wang et al., 2011;0.69 ...
The present study was performed to quantify the dietary magnesium requirement of fingerling Labeo rohita (5.9 ± 0.14 cm; 1.73 ± 0.06 g) by feeding six casein-gelatin based (350 g kg⁻¹ crude protein; 16.72 kJ g⁻¹ gross energy) purified experimental diets with incremental levels of magnesium (0.06, 0.27, 0.46, 0.66, 0.87 and 1.07 g kg⁻¹ diet) to triplicate groups of fish at 08:00, 12:00 and 16:00 h. Live weight gain (LWG), specific growth rate (SGR), feed conversion ratio, protein efficiency ratio, protein gain (PG) and whole body crude protein improved with the increase in dietary magnesium levels up to 0.46 g kg⁻¹ and then stabilized (P >.05). Hepatosomatic index, viscerosomatic index and condition factor improved with increasing levels of dietary magnesium from 0.06 g to 0.46 g kg⁻¹ of diet. However, magnesium concentration in whole body, muscle, vertebrae and scales increased significantly with increase in dietary magnesium levels up to 0.66 g kg⁻¹ of diet, whereupon the response plateaued. Variation in dietary magnesium levels significantly affected liver malondialdehyde content and superoxide dismutase, catalase, glutathione peroxidase and serum alkaline phosphatase (ALP) activities. Broken-line regression analysis of LWG, SGR and PG against dietary levels of magnesium indicated the optimal dietary magnesium requirement of fingerling L. rohita at 0.44, 0.44 and 0.45 g kg⁻¹ of the diet, respectively, whereas that based on magnesium concentrations in whole body and vertebrae and serum ALP activity, it was found to be at 0.66, 0.68 and 0.74 g kg⁻¹ of the diet, respectively.
... Mg is needed for bone, protein, and fatty acid formation, along with the formation of new cells, B vitamin activation, muscle relaxation, blood clot formation, and energy metabolism (Özyurt et al., 2009). In fish, its deficiency can result in loss of appetite, decreased growth, sluggishness, convulsions and eventually death (Ogino and Chiou, 1976). There many literature data on Mg concentrations in fish. ...
Thirty specimens of wels catfish (Silurus glanis) were collected from six stations along the Ticino River between Maggiore Lake and Pavia. For each station the two largest specimens were selected to analyze trace metals in the first rays of the pectoral fin to determine the oldest specimens for each station. A total of 12 samples were processed for age determination and trace metal detection.
After a preliminary treatment with hydrogen peroxide to remove the perishable component, the proximal portions of the spines were cut into thin sections of < 100 μm thickness and mounted on slides. A microscopic analysis was then carried out to count growth rings (annuli) for determining the fish age. Results obtained were compared with ages calculated from the fish length. Fish age based on growth rings counting was much more differentiated (from 3 to 9) than that calculated on the fish length (from 5,3 to 8,4), implying that individual variability and environmental features like food availability and water temperature can result in different growth rates determining different ages for fish of the same length.
The same thin sections were analyzed with Laser Ablation (LA) Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) for determining metal concentrations. Analy-sis was carried out on multiple spots along a radial traversal plane of the spine. Spots near the centre of the spiny ray revealed metal concentrations deposited during the first life year, while those near the perimeter the last life years. By this high-resolution technique, metal exposure and consequent deposition in bone tissues during the fish growth could be reconstructed for a total of 48 elements. After data reprocessing, 13 elements were selected as they were present in concentrations above the detection threshold: Li, B, Mg, Mn, Co, Ni, Cu, Zn, Rb, Sr, Pb, U and Hg.
Statistical analyses were carried out to find mutual relationships among local metal concentrations (correlation analysis) and relationships among metal concentrations, fish age and sampling stations (Generalized Linear Model, GLM). Finally, a regression analysis of the metal concentrations and the distance from the lake was per-formed to verify relationships. Positive correlations were observed between Li and Sr and between Ni, Cu and Zn. Remarkable was also the positive correlation between B and Co. U showed a negative correlation with B, Co and Zn. Finally, a negative correlation between Mg and Rb was observed.
Concentrations of Mg, Rb, Sr and Hg were linearly related with the distance from the lake (regression analysis P < 0,05). Mg concentration increases along the river, while Rb, Sr and Hg concentrations decrease. Considering the well-conserved natural environment of the river, decreasing concentration trends of pollutants can be interpreted as an increase in distance from the source. This is confirmed for Hg contamination; it is known that heavy Hg contamination is present in Maggiore Lake deriving from an industrial plant located in Pieve Vergonte (NO) on the lake’s tributary (Toce River). The chemical production of chlorinated compounds in which Hg is involved as a catalyst stopped more than 20 years ago, but the contamination is still present .
GLM showed that some elements had non-linear relationships with stations. The concentration of Co was much higher in Lanca Ayala than in all other stations. Ni showed significant differences between Somma Lombardo and Turbigo. Pb concentrations showed that Somma Lombardo and Pavia are the most contaminated stations. These two stations are, respectively, the first after Maggiore Lake and the one at the end of the Ticino River, and they correspond to the river stretches flowing just beside urbanized areas, from which a direct input of Pb could have leaked into the river, especially before unleaded gasoline was introduced (1st January 2002).
The LA-ICP-MS methodology used for this study showed great potential. It can effectively ensure in a fast and reliable way a large amount of data with a high age resolution. Obtained data can be subsequently analyzed from multiple points of view, as demonstrated in this work. In some cases the interpretation of results was possible, like Hg and Pb, while in others it requires further insights not included in this report.
... 1981, Satoh, Yamamoto u.a. 1983, Ogino und Chiou 1976. Demgegenüber werden kardiovaskuläre Erkrankungen in der Humanpathologie hauptsächlich mit Mg 2+ -Mangel in Verbindung gebracht (Liao, Folsom u.a. ...
Die salzhaltigen Abwässer des Kalibergbaues führen in natürlichen Süßwassersystemen zu Ionenimbalanzen und einer sekundären Versalzung der Werra in Deutschland. Die Auswirkungen dieser Ionenungleichgewichte auf die Reproduktion von Süßwasserfischen wurden unter Verwendung der Modellfischart Danio rerio untersucht. Angepasst an die aktuellen Grenzwerte für die Einleitung der Abwässer aus dem Kalibergbau wurden fünf verschiedene Kombinationen erhöhter Ionenkonzentrationen getestet. Während eines partiellen Lebenszyklustests wurden adulte Fische 35 Tage lang in den Salzkombinationen exponiert. Anschließend wurden die Nachkommen dieser Fische bis zum 8. Tag nach der Befruchtung den gleichen Salzkonzentrationen ausgesetzt. Zusätzlich wurden Early-Life-Stage-Tests (ELST) mit den Nachkommen von nicht exponierten Eltern durchgeführt. Im Vergleich zu natürlich vorkommenden Ionenkonzentrationen und -verhältnissen in Süßwassersystemen war die Befruchtungsrate der Eier für alle Ionenkombinationen signifikant niedriger, die Koagulations- und Deformationsrate jedoch signifikant höher. Die ELST ergaben bei den Embryonen und Larven u.a. vorzeitige und verlängerte Schlupfzeiten, verringerte Überlebensraten, erhöhte Deformationsraten und Herzschlagfrequenzen sowie Unregelmäßigkeiten des Ganzkörpergehalts von K, Mg, Na und Ca und des Ganzkörper-Ionenverhältnisses von Ca:Mg bei erhöhten Ionenkonzentrationen und Ionenimbalanzen. Im Vergleich zu den Effekten auf die Fortpflanzung und Entwicklung der Nachkommen waren die Effekte auf die adulten Tiere moderat. Die Ergebnisse dieser Dissertation zeigen, dass Teillebenszyklus-Tests besser als Fischeitests oder ELST geeignet sind, die Effekte von durch Abwasser verursachten Ionenimbalanzen, auf die Fortpflanzung und frühe Entwicklung von Süßwasserfischen, zu untersuchen. Weder die momentan gültigen noch die zukünftig herabgesetzten Grenzwerte bis 2027 sind danach als unschädlich, für die Reproduktion von Süßwasserfischen, zu betrachten.
... Calcinosis of the kidney, vertebrae deformity, and degeneration of muscle fibers, epithelial cells of pyloric caeca and gill filaments, were also observed (Lall, 1989). The dietary requirements of rainbow trout, Salmo gairdneri (Cowey et al., 1977; Ogino et al., 1978; Knox et al., 1981), carp, Cyprinius carpio L. (Ogino and Chiou., 1976), Channel catfish, Ictalurus punctatus (Raf.), fingerlings (Gatlin et al., 1982), eel, Anguilla japonica T & S. (Nose and Arai, 1979), guppy, Poecilia reticulate (Peters) (Shim and Ng, 1988) and tilapia, Oreochromis niloticus (L.) (Dabrowska et al., 1989; Reigh et al., 1991) have been estimated in fresh water, and range from 400 to 800 mg/kg dry diet. For marine species, Mg supplementation in the diets may not be necessary (Lall and Bishop,at 45 °C. ...
Japanese seabass, Lateolabrax japonicus (mean initial weight 204.5 g) were fed one of six casein-dextrin-based diets containing graded levels of magnesium (Mg) (184, 278, 487, 929, 1299, and 1737 mg/kg) for 10 weeks with the water-borne Mg concentration of 985 mg/L. Magnesium sulphate was used as the Mg source in the diets. The experiment was carried out in floating sea cages. Growth, survival rate, superoxide dismutase (SOD) activities, glutathione peroxidase (GPx), malondiadehyde (MDA) contents and tissue mineral contents were measured to investigate the effect of dietary magnesium in seabass. After 10 weeks, dietary magnesium supplementation did not improve the growth performance or feed efficiency of adult seabass. On the contrary, negative effects on growth performance, decreased glutathione peroxidase (GPx) and increased malondiadehyde (MDA) contents were observed in seabass fed Mg diets with 929, 1299 mg/kg and 1737 mg/kg, and feed efficiency (FE) exhibited a decreasing tendency with increasing Mg supplemental levels, which indicates the Mg requirement of seabass was met in fish fed the basal diet. Survival, hepatosomatic index, viscerosomatic index, condition factor, and Mg and Ca concentration in whole-body, vertebrae, and scales were not affected by dietary Mg supplementation (P<0.05). © 2015, Israeli Journal of Aquaculture - Bamidgeh. All rights reserved.
... In the present experiment water contained 9.12 mg magnesium dm -3 (Table 1), which was well above the level of 1-3 mg dm -3 considered by Lall (2002) to be too low to meet fish demands. Dietary magnesium requirement values of 0.4-0.5 and 0.6 g kg -1 were reported for C. carpio by Ogino and Chiou (1976) and Dabrowska et al. (1991), respectively. The dietary magnesium levels required for several fish species were summarized by Watanabe et al. (1988): 0.4-0.7 g kg -1 , and by Lall (2002): 0.4-0.8 ...
Six feeding groups of 60 early juveniles (0.6 g) of a rheophilic cyprinid barbel Barbus barbus were reared in triplicate in 18 glass aquaria. Fish fed a commercial formulated dry diet Aller Futura were compared with those on natural food—commercially available frozen Chironomidae larvae at 17, 21 and 25°C. Daily food rations were adjusted according to fish biomass, differences in hydration between the two diets, and rearing temperature. No mortality occurred during experiment. Temperature, and especially diet, both affected whole body proximate and mineral composition of B. barbus juveniles. Under conditions of this experiment the formulated diet Aller Futura seems to satisfy the demands for calcium and magnesium, while an elevated lipid content in this diet was found and marginally deficient phosphorus content can be concluded. These resulted in a depressed content of phosphorus and total minerals in the body, and in elevated lipid content and condition coefficient in the Futura-fed fish, but no visible body deformities occurred. Advantages and limitations of the condition coefficient K were discussed. This is a non-destructive, express indicator that can be used as a supplementary tool for estimation of changes in body proximate composition in fish juveniles of similar size within a population.
... Concentrations of dissolved Mg are low (1-4 mg Mg L −1 ) in freshwater, and uptake of Mg from the environment is considered insufficient to satisfy the metabolic requirements of freshwater fish (Lall, 2002). The dietary Mg requirements of freshwater fish species have been reported for channel catfish (Gatlin et al., 1982), rainbow trout (Knox et al., 1981;Ogino et al., 1978), blue tilapia (Reigh et al., 1991) and common carp (Ogino and Chiou, 1976); the requirements are ranging from 0.2 to 0.7 g Mg kg −1 diet. However, the essentiality of dietary Mg of seawater fish species has not been well studied. ...
A growth trial was conducted to quantify the dietary magnesium (Mg) requirement for hybrid tilapia, Oreochromis niloticus × Oreochromis aureus, reared in freshwater and seawater. A semi-purified basal diet was supplemented with eight levels of magnesium sulfate (0.025, 0.061, 0.082, 0.15, 0.23, 0.30, 0.36 and 0.57 g Mg kg− 1 diet), each was fed to triplicate groups of tilapia (initial body weight: 0.88 ± 0.01 g) reared either in the freshwater or seawater for 8 weeks. The Mg concentration in freshwater and seawater was approximately 4 and 1,400 mg Mg L− 1, respectively. Tilapia reared in freshwater, weight gain (WG) was highest (P < 0.05) in fish fed diets supplemented with ≥ 0.15 g Mg kg− 1 diet, followed by fish fed the diet with 0.061 g Mg kg− 1 diet, and lowest in fish fed the diet with 0.025 g Mg kg− 1 diet. Plasma alkaline phosphatase (ALP) activity was higher in fish fed diets with 0.23 and 0.30 g Mg kg− 1 diet than that in fish fed the unsupplemented diet. The concentration of Mg in whole body, scale, muscle and plasma increased when dietary Mg concentration increase from 0.025 to 0.23 g Mg kg− 1 diet and then stabilized after further increase in dietary Mg. In the seawater reared group, WG, plasma ALP activity, whole body, scale, muscle and plasma Mg concentration of tilapia were similar (P > 0.05) among all dietary treatments. Analysis of WG, ALP activity, whole body, scale, muscle and plasma Mg concentration by broken-line model and whole body Mg retention by linear regression of the fish indicated the optimum dietary Mg requirement for tilapia reared in freshwater is about 0.2 g Mg kg− 1 diet. The result also suggests that dietary Mg beyond 0.025 g Mg kg− 1 is required for tilapia reared in seawater.
Minerals are essential inorganic elements that have a significant impact on growth development and health of fish. Among vertebrates, fish are unique in their ability to absorb minerals from their diets but also from water across gills and skin. Although significant progress has been made in the past 2 decades on requirements of certain minerals (phosphorus, zinc, copper, and selenium), a major gap exists in the uptake, function, biological availability, and excretion of most minerals. Several deficiency signs including cataracts, skeletal deformities, and hatchability of eggs have been linked to trace element deficiencies. In recent years, major shifts from the use of fishmeal to plant ingredients have resulted in a focus on mineral bioavailability; however, interactions between minerals and their uptake from water justify a much broader approach in this area. This chapter provides a brief overview of the known functions, deficiencies, requirements, and bioavailability of minerals and identifies certain issues yet to be resolved.
To investigate the effects of dietary magnesium on growth, feed utilization, nucleic acid ratio and antioxidant status of Heteropneustes fossilis and determine the optimum dietary magnesium requirement, basal diet (400 g/kg crude protein and 17.89 MJ/kg gross energy) supplemented with magnesium sulfate at 0, 2.02, 4.05, 6.08, 8.11 and 10.14 g/kg diet, yielding 0, 0.20, 0.40, 0.60, 0.80 and 1.0 g magnesium per kg of the diet were fed to triplicate groups of fishes. Analyzed values of dietary magnesium were found to be 0.06, 0.28, 0.45, 0.68, 0.88 and 1.05 g/kg. Increasing dietary magnesium levels significantly (P < 0.05) enhanced the absolute weight gain (AWG), specific growth rate (SGR), RNA-DNA ratio, protein retention efficiency (PRE) and protein gain (PG) up to 0.68 g/kg. Biometric indices were also found to improve up to 0.68 g/kg magnesium and then remained static. Antioxidant status in terms of superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) also exhibited significant improvement (P < 0.05) in response to incremental levels of dietary magnesium up to 0.68 g/kg. The whole-body composition also reflected significant changes up to magnesium level of 0.68 g/kg diet. Serum alkaline phosphatase (ALP) activity and magnesium concentration improved with the increasing magnesium level up to 0.88 g/kg diet. Improvement in whole-body and vertebrae mineralization in response to increasing dietary magnesium levels was also noted up to 0.88 g/kg diet. Broken-line regression analysis of SGR, PG, RNA-DNA ratio, serum SOD activity and vertebrae magnesium data against increasing levels of dietary magnesium indicated the optimum requirement of H. fossilis in the range of 0.65-0.79 g/kg diet.
While magnesium requirements for teleost fish highlight the physiological importance of this cation for homeostasis, little is known regarding the molecular identity of transporters responsible for magnesium absorption or secretion. The recent characterization of the vertebrate magnesium transporter solute carrier 41a1 (SLC41a1) in the kidney of a euryhaline fish has provided a glimpse of possible moieties involved in piscine magnesium regulation. The present study obtained a novel SLC41a1 coding sequence for Carassius auratus and demonstrated ubiquitous expression in all tissues examined. Transcriptional regulation of SLC41a1 in response to dietary and environmental magnesium concentrations was observed across tissues. Specifically, decreased environmental magnesium correlated with decreased expression of SLC41a1 in the intestine, whereas the gill and kidney were unaffected. Dietary magnesium restriction correlated with decreased expression of SLC41a1 in the intestine and gill, while again no effects were detected in the kidney. Finally, elevated dietary magnesium correlated with increased expression of SLC41a1 in the kidney, while expression in the intestine and gill remained stable. Plasma magnesium was maintained in all treatments, and dietary assimilation efficiency increased with decreased dietary magnesium. Consumption of a single meal failed to impact SLC41a1 expression, and transcript abundance remained stable over the course of digestion in all treatments. Transcriptional regulation occurred between 7 and 14 days following dietary and environmental manipulations and short-term regulation (e.g. < 24 h) was not observed. Overall the data supports transcriptional regulation of SLC41a1 reflecting a possible role in magnesium loss or secretion across tissues in fish.
In contrast to terrestrial animals, fish can ingest minerals from food or directly from water. Although micro- and macro-elements are needed in small quantities, they play a key role in many metabolic processes. Trace mineral and macromineral deficiencies may go unnoticed due to an absence of clear clinical symptoms in fish. Absorption processes are determined by various factors, mostly mineral concentrations in water but also other water parameters. The required dietary supplementation of macronutrients and micronutrients is very difficult to determine, and the amount of nutrients absorbed by fish from water is equally difficult to measure. Interactions between elements should also be taken into consideration. Many authors emphasize that phosphates may reduce the absorption of most micronutrients. Also, the current parameters of the water can affect the bioavailability. Some elements such as calcium, chlorine and sodium can be absorbed from ambient water in a quantity sufficient to meet the demand for this element. Other elements, however, require supplementation in a diet. For example, studies indicate the need for supplementation of phosphorus, zinc, copper and manganese. Most research concentrates on feedstuff as a source of micro- and macronutrients. Meanwhile, information concerning bioavailability of minerals directly from water is scarce. The aim of this study was to analyse literature from a different perspective, and concentrate on water as a source of minerals in fish nutrition. Measurements of water parameters such as temperature, pH, nitrate and nitrite levels and the amount of dissolved oxygen are a regular component of environmental control in fish farming. Determination of micro- and macro-element levels, however, remains uncommon in aquaculture. Measurements of these parameters could suggest which elements need to be supplemented and which are found in water in amounts that satisfy the needs of the fish.
One of the most important aspects in aquaculture is the nutrition, as for optimum development of organisms, it is essential to have all the necessary nutrients, in terms both of quantity and quality. Nutrients are important for species in culture to stay alive, be healthy and to grow. Even though nutritional principles are similar for all animals, the required level of nutrients varies between species. Animals in production systems need a diet that is properly balanced for the specific requirements of species; however it must also be considered that nutritional requirements are affected by the growth rate, growing conditions, and environmental factors. Knowledge of these allows the formulation of well-balanced and cost-effective feeds. This chapter summarizes information concerning the fate of energy and nutritional requirements of fish and shrimp.
Literature on the mechanisms of magnesium transport through fish intestine is scarce. Indirect evidence for a net magnesium transport via the intestinal tract of fish has been established by dietary experiments (e.g. with carp Cyprinus carpio L. and nile perch Oreochromis niloticus Peters), showing that dietary magnesium is essential for the growth of these fish (Ogino and Chiou, 1976; Dabrowska et al. 1989). Nakamura and Hirano (1986) suggested ‘solvent drag’ as a mechanism for net magnesium transport in eel Anguilla japonica intestine. For mammals, the reports on this topic are equivocal. In the small intestine of the rat, diffusion (Ross, 1962; Aldor and Moore, 1970; O’Donnell and Smith, 1973) as well as solvent drag (Behar, 1974) were reported to underlie magnesium absorption, although the possibility of an active transport component was kept open by these authors. For the intestine of guinea pig, active transport of magnesium was demonstrated (Ross and Care, 1962; Partridge et al. 1987). This communication deals with magnesium transport across stripped intestinal epithelium of freshwater tilapia and its possible mechanisms.
Six semi-purified casein based diets were formulated to contain either a complete mineral mixture (control) or mineral premixes from which a specific test mineral was deleted to obtain phosphorus(P)-free, magnesium(Mg)-free, iron(Fe)-free, zinc(Zn)-free, or manganese(Mn)-free diets. These diets were fed to juvenile milkfish (mean initial weight 2.60±0.08g) for a 22-week experimental period. Final mean percent weight gain ranged from 1022 to 1379% with P-free (1022%) and Fe-free (1066%) diets obtaining a significantly lower weight gain (p<0.01) than the control diet (1270%). Survival was greater than 90% and did not differ significantly among treatments.
Upon termination of the growth experiment, milkfish flesh, bones, and combined samples of head, skin, and scales were dissected and analyzed for ash, P, Ca, Mg, Fe, Zn, and Mn content. The deletion of P or Fe from mineral mixture lowered P content in flesh and bone. Zn content in bone of fish was also lowered by exclusion of Zn, Mn, Mg or Fe. The result of this study demonstrated that it is necessary to supplement P and Fe even to semi-purified casein based diets.
This experiment was conducted to investigate the differences in proximate and mineral compositions between hatchery reared and wild caught yellowtail Seriola quinqueradiata juveniles. The body excluding the stomach, intestine and pyloric cecum of 58- and 70-day-old juveniles produced at Nagasaki Prefectural Institute of Fisheries in 1999 and those of juveniles caught from the coastal area of Kagoshima Prefecture in 1998 and Nagasaki Prefecture in 1999 were analyzed. The crude lipid contents were higher in reared fish than the wild ones. On the other hand, the amount of crude protein in the wild fish was higher compared to the reared ones. Furthermore, the amount of calcium, magnesium, iron, zinc, and copper were different in the two types of fish. These nutritional elements could be important factors in health of the yellowtail juvenile.
Yellow croaker Nibea albiflora, (mean initial weight 28.7 g) were fed on casein based semi purified diets with (control) or without supplement of either magnesium (No-Mg) or iron (No-Fe) over a 14 weeks period at 22-23.5°C. At the end of feeding trial growth performance, hematological characteristics and chemical analysis of the body composition were examined. Growth, feed efficiency and hepatosomatic index in fish fed Fe deficient diet differed significantly from those of control fish. Moreover, hemoglobin content, hematocrit value and plasma Fe content of the fish fed on diet without Fe supplement exhibited significantly lower values, while higher values of plasma triglyceride, total cholesterol and unsaturated iron binding capacity (UIBC) were detected compared to the control group. No difference, however, was noted in the hematological characteristics between the Mg deficient diet and the control. In fish fed Fe deficient diet, slight reduction in bone lipid and in the ash contents of Mn and Cu was observed, though Fe level remained similar to the control. The results obtained from the present study show that Mg requirement can be met from either or both diet or surrounding water, whereas, dietary Fe is essential to prevent anemia in yellow croaker.
Meta-analysis of literature data on mineral and trace element requirements of fish was performed with the major objectives of identifying appropriate response criteria and the factors affecting the minimal dietary inclusion levels. The primary data set included 25 studies on available P, 20 on Ca, 24 on Mg, 5 on K, 37 for Zn, 23 for Se, 19 for Mn, 16 for Fe and 13 for Cu. Broken line regression analysis with linear plateau model (P, Ca, Mg and K) or two-linear line model (Zn, Cu, Fe, Mn and Se) was used for determining the minimal dietary inclusion levels. Vertebral mineral concentration (P, Ca, Zn and Mn), whole-body mineral levels (Mg, K and Fe) and hepatic enzyme activity (Se) were found to be the most appropriate criteria for the respective minerals analysed. In general, weight gain as the criterion resulted in a lower estimate (by 18–42%) than those obtained using whole-body or vertebral mineral concentrations as response criteria. The analysis also showed that different fish species do not show large variations in the mineral and trace element concentrations in the whole body and tissues. Factors such as species group and digestive physiology, type of experimental diet used and dietary interactions, type of mineral source and mineral concentration of water were found to affect the minimal dietary inclusion levels of certain minerals. Besides the meta-analysis, research needs in mineral nutrition of fish with reference to growing changes in dietary strategies and rearing systems are discussed.
A 56-day feed trial was conducted to examine the effect of feeding graded levels of a saltmixture (0-6%), as compared with an established mineral supplement (4%, McCollum’s salt-mixture no. 185 plus trace elements), on the growth and body composition of carp. Fish fed the ration containing 4% McCollum’s salt-mixture plus trace elements displayed the highest overall growth response and feed efficiency over the experimental test period. For those fish fed graded levels of the salt-mixtures, maximum growth was obtained at the 2% inclusion level. In contrast to fish fed mineral supplemented rations, fish fed a ration containing no mineral supplement displayed reduced growth, low feed efficiency, loss of muscle tone, decreased heamatocrit, decreased haemoglobin and serum glucose concentration, elevated carcass moisture, Ca, P and Na content, and reduced carcass protein, lipid, Mg, Fe, Zn and Cu content. The data present indicates the necessity of a dietary mineral supplement for carp fed a purified ration based on casein, potato starch, dextrin and lipid. © 1984, The Japanese Society of Fisheries Science. All rights reserved.
This chapter examines the mineral requirements of finfish and compares the mineral metabolism of fish with that of other animals. Fifteen trace elements are considered to be essential in animals. Among these, the physiological role of a deficiency of chromium, cobalt, copper, fluorine, iodine, iron, manganese, molybdenum, selenium, and zinc is well recognized. Most of these trace elements have been detected in fish tissues; however, the essentiality of only a few of these elements has been demonstrated. The main functions of essential elements in the body include the formation of skeletal structure, maintenance of colloidal systems (osmotic pressure, viscosity, diffusion), and regulation of acid–base equilibrium. They are important components of hormones, enzymes, and activators of enzymes. Calcium and phosphorus are required for the formation of the skeletal structures of the body. Sodium, potassium, and chloride, along with phosphates and bicarbonates, maintain homeostasis and the acid–base balance. A fixed number of specific trace metals are firmly associated with a specific protein in metalloenzymes, which produce a unique catalytic function. Although aquatic organisms readily absorb metals from the environment, their ability to regulate abnormal concentrations varies with the species. Defining the role of inorganic elements in immune response, disease prevention, and reproduction of fish is an important and interesting area of research. Recent advances in molecular biology, microscopy, and analytical chemistry now provide us with many opportunities to explore the trace element metabolism and regulation in fish.
Feeding experiments were conducted to examine the availability to rainbow trout of manganese (Mn) and magnesium (Mg) contained in white fish meal and to determine the minimum supplemental Mn and Mg levels to white fish meal based diet for the normal growth of rainbow trout. The lowest growth was observed in fish receiving a diet without supplemental Mn or Mg and the growth was effectively improved by the addition of Mn and Mg at levels of more than 15 μg/g and 0.5 mg/g, respectively. The Mn content of vertebrae was lowest in fish fed a diet without supplemental Mn and was proportional to dietary Mn levels, reaching a plataeu by supplementing more than 15 μg/g diet. The ratio of Ca to Mg in the vertebrae was highest in fish fed a diet without supplemental Mg and effectively decreased to lower levels by Mg supplementation at levels more than 0.5 mg/g diet. The results of these experiments have demonstrated that supplementation of Mn and Mg at more than 15 μg/g and 0.5 mg/g, respectively, to white fish meal diet is necessary to sustain the normal growth of rainbow trout. The results also suggested that the availability of Mn in white fish meal was very low and that the utilization of Mg absorbed was distorted by a certain substance in white fish meal. © 1991, The Japanese Society of Fisheries Science. All rights reserved.
One of the macro elements, Magnesium (Mg) found in the heart, liver and kidney tissues was analyzed and compared between wild/fattened and female/male Bluefin Tuna (BFT) in the Turkish region of the Eastern Mediterranean. For this purpose, 110 individual (i.e., 55 female and 55 male) samples of wild and fattened tuna were investigated. Mean Mg levels in the heart, liver and kidney tissues of wild BFT were found to be as follows: 42.52, 46.73 and 38.60 mg/100 g w wt. Analogous data for the fattened fish were as follows: 38.06, 49.74 and 41.13 mg/100 g w wt. In comparison of wild with fattened fish, Mg differences in the heart, liver and kidney tissues were significant (p<0.05). In terms of gender, mean Mg values in the heart, liver and kidney tissues of 55 wild and 55 fattened individual female BFT were analyzed, respectively to be as follows: 45.12, 49.47, 41.08 and 38.37, 51.02, 44.24 mg/1 OOg w wt. Additionally, these parameters for the same tissues of 55 wild and 55 fattened male specimens were detected, respectively to be as follows: 39.93, 43.98, 36.12 and 37.74, 48.45, 38.02 mg/100 g w wt. According to gender, differences in levels of Mg in the heart and kidney tissues of wild vs. fattened female samples were significant except for liver tissues (p<0.01) however, for male specimens, differences in Mg in the same tissues of wilds vs. females were significant (p<0.05).
The experiment tested three formulated dry diets at 25°C to determine their effects on larval Barbus barbus (L.) body mineral composition, growth, and survival. Live Artemia nauplii were fed to all the larvae for the first 5 days of the experiment. From day 6 to day 25 inclusive, nauplii were the reference diet in one group, whereas the three other groups were fed dry diets exclusively. On D1 the fish body comprised 6.71% ash, 1.20% P, 0.35% Ca, and 0.09% Mg (dry matter), but initial feeding with nauplii resulted in increased values of all these components. The highest statistically significant (P ≤ 0.05) final body ash and mineral content was recorded for larvae fed nauplii (ash 13.22%; P 2.04%; Ca 2.95% and Mg 0.15%; d.m.). Fish fed nauplii grew faster than those fed dry diets (final mean BW 214.5 mg and 84.3-118.9 mg, respectively; all differences significant), and their final survival rate was also significantly the highest (99.9% and 96.5-99.4%, respectively). As evidenced by the current results, even short-term (20 days) feeding exclusively dry formulated diets can lead to considerable deficiencies in essential minerals in the larval body.
Meta-analysis of literature data on mineral and trace element requirements of fish was performed with the major objectives of identifying appropriate response criteria and the factors affecting the minimal dietary inclusion levels. The primary data set included 25 studies on available P, 20 on Ca, 24 on Mg, 5 on K, 37 for Zn, 23 for Se, 19 for Mn, 16 for Fe and 13 for Cu. Broken line regression analysis with linear plateau model (P, Ca, Mg and K) or two-linear line model (Zn, Cu, Fe, Mn and Se) was used for determining the minimal dietary inclusion levels. Vertebral mineral concentration (P, Ca, Zn and Mn), whole-body mineral levels (Mg, K and Fe) and hepatic enzyme activity (Se) were found to be the most appropriate criteria for the respective minerals analysed. In general, weight gain as the criterion resulted in a lower estimate (by 18–42%) than those obtained using whole-body or vertebral mineral concentrations as response criteria. The analysis also showed that different fish species do not show large variations in the mineral and trace element concentrations in the whole body and tissues. Factors such as species group and digestive physiology, type of experimental diet used and dietary interactions, type of mineral source and mineral concentration of water were found to affect the minimal dietary inclusion levels of certain minerals. Besides the meta-analysis, research needs in mineral nutrition of fish with reference to growing changes in dietary strategies and rearing systems are discussed.
Information on nutritional requirement of some Brazilian farmed fish species, especially essential amino acids (EAA) requirements, is scarce. The estimation of amino acids requirements based on amino acid composition of fish is a fast and reliable alternative. Matrinxa, Brycon amazonicus, and curimbata, Prochilodus lineatus, are two important Brazilian fish with potential for aquaculture. The objective of the present study was to estimate amino acid requirements of these species and analyze similarities among amino acid composition of different fish species by cluster analysis. To estimate amino acid requirement, the following formula was used: amino acid requirement = [(amount of an individual amino acid in fish muscle tissue) × (average totalEAA requirement among channel catfish, Ictalurus punctatus, Nile tilapia, Oreochromis niloticus, and common carp, Cyprinus carpio)]/(average fish muscle totalEAA). Most values found lie within the range of requirements determined for other omnivorous fish species, in exception of leucine requirement estimated for both species, and arginine requirement estimated for matrinxa alone. Rather than writing off the need for regular dose–response assays under the ideal protein concept to determine EAA requirements of curimbata and matrinxa, results set solid base for the study of tropical species dietary amino acids requirements.
Objective: The objective of the present study is to study the toxicity of Magnesium oxide nanoparticle and Magnesium oxide bulk against two fishes (Tilapia (Oreochromis mossambicus) and Zebra fish (Danio rerio) for toxicity. The Biochemical and antioxidant activity were also studied in both control and the injected fish. Bioaccumulation was also studied. Methods: Magnesium oxide bulk and Nano particles were prepared by dissolving it in 1μg/mL concentration and sonicated for half an hour. Different concentrations of Magnesium oxide both bulk and nano particles from 10 to 200 ppm were determined. Results: There was a significant decrease in protein. In the Catalase activity there was a gradual and sporadic increase. The specific activity of GST enzyme increased significantly with an increase in the concentration of Magnesium nanoparticles. There was an increase in the concentration of Magnesium nanoparticles and more accumulation was seen. Conclusion: Heavy metals are common pollutants and restricted to frequent inhalation in aquatic organism due to their larger size. The results revealed that magnesium oxide bulk particle was found to be more toxic when compared to nano particle.
Common carp juveniles were fed for 9 weeks one of the eight semipurified diets containing graded levels of magnesium, 0.08, 0.6, 1.1, 3, 2 g Mg kg−1 and 25 or 44% protein.
Fish growth and feed utilization were significantly affected by both Mg and protein levels in the diets. Significant interaction between these two studied variables existed in relation to the fish performance as well as to mean deposition rate of several minerals in common carp body. The fish fed diets containing 0.08 g Mg kg−1 had reduced growth and developed deficiency signs such as muscle flaccidity and skin hemorrhages.
Results indicated that a minimum Mg level of 0.6 g Mg kg−1 was required to elevate plasma and bone magnesium content and to reduce the whole body Ca concentration (hypercalcinosis symptom). Further increase of dietary Mg up to 3.2 g Mg kg−1 improved growth rate of fish insignificantly, but the deposition rate of dietary Mg fell to as low as 7.4 and 10.7 percent in low- and high-protein diet fed fish, respectively. In Mg-deficient fish, considerable amount of magnesium was absorbed via extra-oral routes, however, this way of the covering magnesium need becomes insufficient in fast growing fish.
Lysine is a strictly essential amino acid, the reference for dose-response trials to determine dietary amino acids requirements of fish. This study compares estimation of amino acids requirements of largemouth bass, Micropterus salmoides, from data of lysine dose-response trials, analyzed through different statistical methods: Polynomial regression analysis, broken-line regression analysis, and specific mathematical modeling. Amino acids requirements were estimated through the A/E relationship [A/E = (essential amino acid ÷ total essential amino acids + cystine + tyrosine) × 1.000]. Groups of 25 feed-conditioned largemouth bass fingerlings (1.29 ± 0.03 g; 4.35 ± 0.17 cm) were stocked in 60-L cages (5 mm mesh) housed in 1,000-L plastic, indoor tanks, closed circulation system, and fed diets containing 1.0, 1.5, 2.0, 2.5, 3.0, or 3.5% lysine, in a totally randomized experimental design trial (n = 4). The broken-line analysis method yielded more reliable and precise estimations of lysine requirements–2.1% of diet or 4.9% dietary protein–for final weight, weight gain, and specific growth rate. Best-feed conversion ratio was attained with 1.69% lysine in the diet or 3.9% lysine in dietary protein. Body amino acids profile was an adequate reference for estimation of largemouth bass amino acids requirements.
The growth rate and magnesium concentration in scales, bone and muscle of freshwater tilapia, Oreochronüs mossambicus (Peters), initially weighing between 70 and 300 g, were followed during low-magnesium feeding. The growth rate decreased in fish on low-magnesium diets, but no changes were observed in the magnesium concentration in the scales, bone or muscle. No changes were observed in calcium or sodium concentrations in these tissues. We conclude that adult tilapia fed a low-magnesium diet manage, in contrast to other fish species, to maintain their magnesium balance and must therefore obtain magnesium from the water.
The value of a biochemical approach to animal and particularly fish nutrition is frequently questioned. This chapter points out that there is no sharp dividing line between proper nutrition and inadequate nutrition. It seems abundantly clear that progress toward attaining optimal nutrition depends on an understanding of the metabolism of both the whole organism and of the cell.. The most significant recent advance has been the quantitative definition of the essential amino acids required by the Japanese eel—Anguilla japonica—and by the carp—Cyprinus carpio. Few amino acid deficiencies are known to lead to characteristic pathological symptoms. Rather, nearly all give rise to a loss of appetite, resulting in low food intake with a consequent fall in growth rate and activity. Recently, however, more specific symptoms have been described in rainbow trout given diets lacking tryptophan. Trout deficient in tryptophan showed transient scoliosis, and the notochord of all scoliotic fish was affected by a protrusion of fibrous material, on the concave side of the fish, between the cartilaginous processes.
Whole body magnesium concentrations were found to reflect the magnesium status of juvenile rainbow trout (Salmo gairdneri) fed semi-purified diets containing graded levels of magnesium (36–2120 mg/kg diet). Low whole body concentrations (<300 mg/kg wet basis) preceded growth reduction or other signs of clinical deficiency. Whole body concentrations greater than 370 mg/kg were indicative of magnesium sufficiency. Trout met a considerable portion of their requirement by direct uptake from the environment in fresh water containing a low level of magnesium (1.3 mg/l). Analysis of growth and whole body Mg concentration data using analysis of variance suggests that trout require about 0.06% of their diet as Mg. Analysis of the same data using dose-response curves indicates an optimum dietary Mg level near 0.14% of the diet.
The requirement of the guppy (Poecilia reticulata Peters) for dietary magnesium was investigated by feeding diets containing levels of magnesium (0.0, 0.18, 0.36, 0.54, 0.72, 0.90 g/kg of dry diet) for about 3.5 months. Poor growth, low feed efficiency, and high mortality were demonstrated in magnesium-deficient guppies. Magnesium, calcium, sodium and potassium content of the kidney, heart, liver, muscle and bone were determined. Most of the organs in magnesium-deficient fish tended to have low magnesium and potassium but high calcium and sodium concentrations. The level of magnesium required for optimal growth was found to be 0.54 g/kg of diet.
The incorporation of powdered marine microalgae in fish diets can substitute, at least in part, for the addition of minerals to the diet. In diets for freshwater fishes, the incorporation of 33% of powdered marine microalgae can supply some of the mineral element requirements. The incorporation of microalgal powder in diets for marine fishes appears more effective, since lower percentages are needed to cover the mineral requirements. Most mineral needs of turbot can be covered with low percentages of marine microalgal powder in the diet: 3.8% of Tetraselmis suecica, 5.7% of Isochrysis galbana, 3.57% of Dunaliella tertiolecta and 3.9% of Chlorella stigmatophora. Mn and Co must, however, be added. Thus, incorporation of small amounts of marine microalgae in diets can replace a mineral mixture.
The concentrations of 14 mineral elements (Na, K, Ca, P, Mg, Fe, Zn, Cu, Mn, Co, Cr, Ni, Cd and Pb), together with pH, moisture, ash and NaCl content, were determined in 38 feeds commonly available in Europe for trout (starter, fingerling, grower, brood), salmon (starter, fingerling, grower), eel (grower), and larval fishes.Large differences in the mineral composition, particularly the trace elements Fe, Zn, Cu, Mn, Co and Pb, exist within and between the different feed categories tested. The results obtained are discussed in the context of available information on the dietary mineral requirements of these fish species.
Neutron activation analysis and 28Mg2+ as radiotracer were used to measure magnesium distribution in fish and magnesium flows between carp and water. A novel tracer kinetic approach was applied to determine magnesium flows “to fish from water” and “to water from plasma (fish)” (Fwp). This revealed that and thus pointing to another magnesium source than water, namely food.
The magnesium handling of freshwater teleost fish is discussed, with an emphasis on the role of branchial, intestinal and renal transport. In response to the eminent threat of constant diffusive losses of minerals such as magnesium, freshwater fish have developed efficient mechanisms for magnesium homeostasis. Magnesium losses are overcome by the uptake of magnesium from the food, making the intestine an important route for magnesium uptake. Some evidence suggests that intestinal magnesium uptake in fish is a regulated, cellular process. The ambient water is an additional magnesium source for fish, implicating the gills as a secondary route for magnesium uptake. Certainly, in some species, direct uptake from the water, probably via branchial routes, ameliorates the effects of a low-magnesium diet. The hard tissues, representing over 50 % of the total body magnesium pool, form a reservoir from which magnesium can be recruited to perform its functions in the cellular metabolism of soft tissues such as muscle. In fish, as in terrestrial vertebrates, the balance of a variety of elements becomes disturbed when the magnesium homeostasis of the soft tissues is disrupted. However, fish appear to be less sensitive than terrestrial vertebrates to these perturbations. Magnesium is reabsorbed in the kidneys to minimise losses. For renal cells, part of a cellular pathway has been elucidated that would allow absorptive magnesium transport (a magnesium conductive pathway in renal brush-border membranes). In some euryhaline teleosts, the kidneys appear to switch instantaneously to rapid magnesium secretion upon magnesium loading, a response common to marine fish that are threatened by diffusive magnesium entry. This enigmatic mechanism underlies the capacity of some euryhaline species to acclimate rapidly to sea water. Despite the progress made over the last decade, much of the cellular and molecular basis of magnesium transport in the gills, intestine and kidneys remains obscure. The application of fluorescent, radioactive and molecular probes, some of which have only recently become available, may yield rapid progress in the field of magnesium research.
Freshwater tilapia feeding on a diet containing 1 mmol kg−1 magnesium (control diet: 30 mmol kg−1) grow although at a decreased rate. The diet does not noticeably affect the blood ionic composition. Prolactin cell activity increases in these fish as judged from the enhanced rate of synthesis of 3H-leucine labelled prolactins in vitro and the ultrastructure of the cells. Na+ intake and Na+ loss decreases, and chloride cell density increases, phenomena typical for enhanced prolactin cell activity in tilapia. We conclude that tilapia manage to cope with a dietary magnesium insufficiency and suggest that prolactin is involved in the acclimation to this diet.
The euryhaline Mozambique tilapia (Oreochromis mossambicus) shows a more marked ability to adapt to low magnesium levels in food and water than many other fish species. Nonetheless, the internal distribution of magnesium is altered under low-magnesium conditions. The amount of magnesium in scales, and to a lesser extent the vertebral bone, is reduced and hence serve as magnesium reservoirs. The magnesium concentration of muscle is only marginally reduced by low external magnesium, suggesting that magnesium is partitioned to ensure normal muscle functioning. The water magnesium is of vital importance, as exposure to low-magnesium water markedly deminished the ability of tilapia to adapt to low-magnesium feeding. However, magnesium intake from the water, eithervia the integument or drinking, does not increase in lowmagnesium fed fish, despite an increased opercular chloride cell density. The growth related magnesium accumulation of tilapia under low-magnesium conditions approximates the total intake of the element (from the food and from the water), indicating that magnesium losses are minimized and that the magnesium absorption from the gastrointestinal tract may be highly efficient and very important.
Rapsmehl in Rationen für Warmwasser-Karpfen II. Biochemische Parameter als Indices für die Proteinqualität
Es wurde der Einfluß von unterschiedlichen Proteinquellen auf die Zusammensetzung und das Niveau der freien Aminosäuren im Muskelgewebe und des Hepatopankreas des Karp-fens untersucht. Darüberhinaus wurde die Aktivität der Aminotransferasen (GOT und GPT) in beiden Geweben bestimmt. Sowohl der Einsatz von Fischmehl als auch von ver-schieden hergestellten Rapsmehlen führte zu deutlichen Unterschieden im Gehalt von freien Aminosäuren im Muskelgewebe und Hepatopancreas. Bei niedrigen Proteingehalten in der Ration stieg der Gehalt an Serin und Alanin. Die Aktivität der Aminotransferasen zeigte im Fischgewebe eine gewisse Variation, die aber nicht in Beziehung zu den eingesetzten Proteinquellen stand.
A growth trial was conducted to estimate the optimum concentration of dietary magnesium (Mg) for grass carp (Ctenopharyngodon idella). Triplicate groups of grass carp (5.56 ± 0.02 g) were fed diets containing graded levels (187, 331, 473, 637, 779 and 937 mg kg−1) of Mg for 8 weeks. Weight gain, specific growth rate and feed efficiency were linearly increased up to 637 mg kg−1 dietary Mg and then levelled off beyond this level. For body composition, dietary Mg levels higher than 473 mg kg−1 significantly decreased the moisture content but increased the lipid content of whole body, muscle and liver. Dietary Mg levels higher than 473 mg kg−1 significantly decreased the ash contents of vertebrae, scales and muscle. Mg contents in whole body, vertebrae, scales and plasma were increased up to 637 mg kg−1 dietary Mg and then levelled off beyond this level. However, Ca and P contents seem to be inversely related to dietary Mg. Dietary Mg levels higher than 473 mg kg−1 significantly decreased Zn and Fe contents in whole body and vertebrae. Broken-line analysis indicated that 687 mg kg−1 dietary Mg was required for maximal tissue Mg storage, as well as satisfied for the optimal growth.
To determine dietary magnesium (Mg) requirements of juvenile grass carp, Ctenopharyngodon idella, magnesium sulphate was added to the basal diet at 0, 150, 300, 600, 1200, 2400 mg Mg kg−1 diet. Each diet was fed to three replicate groups of juvenile grass carp (initial weight: 7.69 ± 0.13 g) in a closed, recirculating rearing system for 76 days. No mortality or nutritional deficiency signs were observed except the growth depression in fish fed the Mg-deficient diet. Growth performance and activities of serum superoxide dismutase (SOD), glutathione peroxidase (GPx) and lysozyme (LSZ) were highest (P <0.05) in fish fed the diet supplemented with 600 mg Mg kg−1. The serum malondialdehyde (MDA) content was higher (P <0.05) in fish fed the diets supplemented with 0 and 150 mg Mg kg−1 than that in fish fed the diets with ≥300 mg Mg kg−1. Mg concentrations both in whole-body and vertebrae increased with the increase in dietary Mg level up to 300 mg kg−1, whereupon the response reached a plateau. Analysis by second-order polynomial regression of weight gain, by broken-line regression of vertebrae Mg concentration and by linear regression of whole-body Mg retention of fish indicated that the adequate dietary Mg concentration for juvenile grass carp was 713.5, 627.7 and 469.8 mg kg−1 diet, respectively.
Most of magnesium (Mg) in fish is located in the bone. Dietary calcium (Ca) and phosphorous (P) has been reported to affect scales and vertebrae Mg dramatically in juvenile grouper, but the effect of dietary Mg on tissue Ca and P is unknown. This study was conducted to investigate the effect of dietary Mg supplement on growth, feed efficiency, morphometry, and the ash and Ca, P, sodium (Na) content in scales and vertebrae of juvenile grouper. Seven experimental diets were formulated to contain graded levels of Mg by supplementing the basal diet with 0, 200, 400, 600, 800, 1000 and 2000 mg kg−1 Mg in the form of Mg sulphate (MgSO4·7H2O). Juvenile grouper with an initial body weight of 11.8 ± 0.1 g were fed to apparent satiation twice per day for 10 weeks. Dietary Mg supplement had no significant effect on growth, feed efficiency, and Mg concentration in scales and vertebrae of grouper, which indicates the Mg requirement of grouper was met in fish fed the basal diet. Mg supplements had significant effect on morphometry index such as body length, condition factor, viscera somatic index and mesenteric fat index. Extra dietary Mg supplement to the basal diet had no negative effect on ash, Ca and P concentrations in scales and vertebrae.
Replacement of fish meal with plant products in aquafeeds results in the elimination of dietary compounds which may be important for optimal growth and physiology. A study was conducted to determine if supplementation with macro-minerals and/or inositol would improve performance of rainbow trout (Oncorhynchus mykiss) fed a plant-based diet. Four iso-caloric and iso-nitrogenous diets (40 g kg−1 protein and 15 g kg−1 lipid) were formulated and consisted of a fish meal-based control diet (control) and three plant-based experimental diets. Plant-based diets were supplemented with either macro-minerals and inositol (+MM+I), no macro-minerals with inositol (−MM+I), and no macro-minerals and no inositol (−MM−I). Sodium chloride, potassium chloride and magnesium oxide were the sources used in the macro-mineral premix. There was no effect of diet on survival, but there was an effect of diet on weight gain, FCR, feed intake, HSI and nutrient retentions. Significant liver pathology was observed in trout fed plant-based diets without MM supplementation. Supplementation of MM and inositol significantly improved weight gain of trout fed a plant-based diet. Supplementation of MM and/or inositol also improved PRE and ERE. This study demonstrates the importance of supplementing these nutrients to trout fed fish meal free diets.
Diets containing graded levels of salt-mixture (McCOLLUM's salt-mixture no. 185 plus trace elements) were given to young rainbow trout and carp for 50 days. Dietary levels of the salt-mixture exerted a strong influence on growth and mortality in rainbow trout and on growth in carp. Rainbow trout were more sensitive to the lack of the dietary salt-mixture than carp. The diet deficient in the salt-mixture resulted in retarded growth, high mortality, anemia and malformation of the head in rainbow trout. The optimal content of the salt-mixture in the diet was proven to be 4 to 5% for both species under the present experimental conditions.