Dietary copper requirement of fingerling channel catfish

Purified egg white diets containing incremental levels of copper (as CuSO₄·5 H₂O) were fed to fingerling channel catfish (Ictalurus punctatus) to determine their dietary copper (Cu) requirement. Catfish in aquaria were fed diets containing 0, 2, 4, 6, 8 or 10 mg of supplemental copper/kg diet for 13 weeks. Growth and feed efficiency data, as well as hemoglobin, hematocrit and erythrocyte count values were similar for catfish fed the basal diet which contained 0.89 mg Cu/kg diet and all copper-supplemented diets. A diet containing 40 mg of supplemental copper/kg was also fed in this experiment since 16 and 32 mg of supplemental copper/kg had previously been reported to cause suppressed growth of channel catfish. Those fed the 40 mg of supplemental copper/kg diet had similar growth and feed efficiency values as catfish fed the other diets. At the end of week 13, heart cytochrome c oxidase and liver copper—zinc superoxide dismutase activities were significantly reduced in catfish fed diets containing 0 and 2 mg of supplemental copper/kg as compared to those fed 4 mg/kg or more of supplemental copper. Based on the enzymatic data, the minimum dietary copper requirement of channel catfish was determined to be approximately 5 mg of total copper/kg diet.     

Studies on the manganese requirement of fingerling channel catfish

Fingerling channel catfish (Ictalurus punctatus) were fed purified diets containing varying levels of manganese for 13 weeks in two experiments. Weight gain and feed efficiency data of catfish fed the basal diet (2.4 mg Mn/kg diet) were not significantly different from those of catfish fed manganese-supplemented diets in both experiments. Liver manganese superoxide dismutase activity, liver manganese concentration, serum alkaline phosphatase activity and hexosamine content of gill filament cartilage did not differ in catfish fed basal and manganese-supplemented diets. Bone manganese concentration increased almost linearly with increasing dietary manganese levels. The 2.4 mg Mn/kg supplied by the basal diet was apparently sufficient to meet the manganese requirement of fingerling channel catfish during these experiments.     

Dietary arginine requirement of fingerling Indian catfish (Heteropneustes fossilis, Bloch)

An 8-week feeding trial was conducted to determine the dietary arginine requirement of fingerling Indian catfish, Heteropneustes fossilis (6.25 ± 1.30 cm, 4.8 ± 0.65 g). Six isonitrogenous (400 g Kg^?1) and isoenergetic (17.90 kJ g^?1) amino acid test diets were formulated with gradation of 2.5 g Kg^?1 containing graded levels of l-arginine (8.5–21.0 g Kg^?1, dry diet). Fish were randomly stocked in triplicate groups, in 75-l circular trough with flow-through system and fed experimental diets at 4 % BW/day at 0800 and 1800 h. Maximum live weight gain (277 %), best feed conversion ratio (FCR) (1.52) and protein efficiency ratio (PER) (1.64) were obtained in fish fed diet containing 16.0 g Kg^?1 arginine. However, quadratic regression analysis of live weight gain, FCR, PER and body protein deposition (BPD) data indicated requirements for dietary arginine at 16.80, 16.30, 16.11 and 16.10 g Kg^?1 of dry diet, respectively. Significantly (p < 0.05) higher whole body protein content, minimum carcass moisture and intermediate carcass fat contents were recorded at 16.0 g Kg^?1 dietary arginine diet. Ash content remained insignificantly (p > 0.05) low among all the treatments except at diet I and diet II. Based on the above results, it is recommended that the diet for young H. fossilis should contain arginine at 16.32 g Kg^?1, dry diet, corresponding to 40.80 g Kg^?1 dietary protein for optimum growth and efficient feed utilization.     

Quantifying the dietary biotin requirement of the catfish,Clarias batrachus

Asian catfish, Clarias batrachus, were fed semi-purified basaldiets containing 0, 0.1, 0.5, 1, 3 and 5 mg biotin kg^–1diet for 60 days. Fish fed the control diet (no biotin) showed(P < 0.05) higher mortality, lower weight gain, specificgrowth rate (SGR), feed efficiency ratio (FER) and protein efficiencyratio (PER) than in fish fed diets supplemented with biotin. The highestweight gain, SGR, FER and PER were noticed in fish fed 1 mg biotinkg^–1, followed by 0.5, 5, 3 and 0.1 mg biotinkg^–1, except for PER (followed by 0.5, 5, 0.1 and 3 mgbiotin kg^–1). Quadratic analysis showed that the optimumdietary biotin requirements for maximal weight gain, PER and PER were2.49, 2.54 and 2.52 mg kg^–1, respectively. Liver biotinconcentrations were influenced by levels of biotin in the diet.Concentration of liver biotin increased as level of dietarysupplementation increased and no biotin was detected in the liver of thecontrol fish. Liver pyruvate carboxylase and acetyl CoA carboxylaseactivities were higher in fish fed biotin-supplemented diets than incontrols. Biotin concentrations, pyruvate carboxylase and acetyl CoAcarboxylase activities in liver associated with normal growth rangedfrom 10.59 to 10.66 g g^–1, 147.97 to 148.18 units mgprotein^–1 and 12.76 to 12.78 units mg protein^–1, respectively. Biotin deficiency symptoms such as anorexia, darkskin colour and convulsions were observed in fish fed the control diet.The optimum dietary biotin requirement for maximal growth of C.batrachus is about 2.49 mg kg^–1 diet.     

An estimate of the dietary calcium requirement of fingerling Tilapia aurea reared in calcium-free water

Seven isocaloric and isonitrogenous semi-purified diets which contained graded levels of calcium ranging from 0.17 to 3.20% were fed to fingerling Tilapia aurea for a period of 11 weeks. The fish were maintained in a flow-through aquarium system supplied with calcium-free well water. Growth, feed conversion and bone composition data indicated that between 0.17 and 0.65% dietary calcium was adequate for optimum growth and normal bone mineralization.     

Dietary L‐tryptophan requirement of fingerling stinging catfish,Heteropneustes fossilis (Bloch)

To quantify dietary L‐tryptophan requirement of fingerling Heteropneustes fossilis (6.66 ± 0.08 g), casein–gelatin‐based isonitrogenous (38% CP) and isoenergetic (14.72 kJ g^?1 DE) purified diets with eight levels of L‐tryptophan (0.12%, 0.16%, 0.20%, 0.24%, 0.28%, 0.32%, 0.36%, 0.40% dry diet) were fed to triplicate groups of fish twice daily to apparent satiation for 12 weeks. Incremental levels of dietary tryptophan from 0.12 to 0.28% significantly (P < 0.05) improved absolute weight gain (AWG; 14.3–65.9 g fish^?1), feed conversion ratio (FCR; 5.9–1.5), protein retention efficiency (PRE; 6.2–32.2%), haemoglobin (Hb; 6.5 to 11.9 g dL^?1) and haematocrit (Hct; 23.5–33.8%). To determine the precise information on tryptophan requirement, data were subjected to broken‐line and second‐degree polynomial regression analysis. Broken‐line regression analysis reflected highest R² values for AWG g fish^?1 (0.999), PRE% (0.993), Hb g dL^?1 (0.995) and Hct% (0.993) compared with R² values obtained using second‐degree polynomial regression analysis of AWG g fish^?1(0.949), PRE% (0.890), Hb g dL^?1(0.969) and Hct% (0.943), indicating that data were better fit to broken‐line regression analysis. Hence, based on broken‐line regression analysis at 95% maximum response, tryptophan requirement of fingerling H. fossilis is recommended between 0.24% and 0.27% dry diet (0.63–0.71% protein).     

Effects of feeding diets containing an imbalance of branched-chain amino acids on fingerling channel catfish

A series of studies was conducted to investigate the effects of feeding diets imbalanced with respect to branched-chain amino acids on channel catfish. Basal diets contained casein and gelatin supplemented with crystalline L-amino acids to correspond to the amino acid pattern found in 24% whole egg protein except for the branched-chain amino acids. Basal diets were formulated to be deficient in either leucine, isoleucine, or valine. Excess levels of either leucine, isoleucine, or valine were added to the appropriate basal diet. Growth and feed efficiency data demonstrate that excess leucine depressed growth of fish fed diets deficient in isoleucine or valine, but not in diets adequate in branched-chain amino acids. The deleterious effects of excess leucine could be reversed by supplementation with the deficient amino acid, but not by the other branched-chain amino acid. Growth was also depressed in fish fed excess isoleucine but not valine in leucine-deficient diets. Serum levels of isoleucine and valine suggest that leucine may control the tissue uptake of these amino acids in the channel catfish.     

Effects of feeding soybean meal with varying trypsin inhibitor activities on growth of fingerling channel catfish

Uncooked hexane extracted soybean meal was heated for various lengths of time to produce meals with varying trypsin inhibitor activities. Fingerling channel catfish (Ictalurus punctatus) were fed 25 and 35% crude protein practical type test diets containing soybean meal with graded levels of trypsin inhibitor activity for 10 weeks. Growth rates and protein efficiency ratio (PER) values were reduced in fish fed raw and inadequately heated soybean meal at both protein levels. These effects were more severe at the lower dietary protein level. Growth rates and PER values improved in each study as the trypsin inhibitor activity of the soybean meal decreased to tolerable levels. Fish fed the 35% crude protein diets appeared to tolerate soybean meal with much higher trypsin inhibitor activity than fish fed the 25% crude protein diets. Even though growth rates and PER values were not significantly different over a rather wide range of dietary trypsin inhibitor activities, the best growth rates were not observed at either protein level until about 83% of the trypsin inhibitor activity in the soybean meal had been destroyed.     

Dietary amino acid l-tryptophan requirement of fingerling Indian catfish, Heteropneustes fossilis (Bloch), estimated by growth and haemato-biochemical parameters

An 8-week feeding trial was conducted to determine the dietary tryptophan requirement of fingerling Indian catfish, Heteropneustes fossilis (6.10 ± 1.15 cm, 4.44 ± 0.50 g). Six isonitrogenous (40 g 100 g^?1) and isoenergetic (17.90 kJ g^?1) amino acid test diets were formulated with gradation of 0.1 g 100 g^?1 containing graded levels of l-tryptophan (0.04–0.54 g 100 g^?1, dry diet). Fish were stocked in triplicate groups, in 75-L circular trough with flow-through system and fed experimental diets at 4% BW/day twice daily. Maximum live weight gain (258%), best feed conversion ratio (FCR) (1.54) and protein efficiency ratio (PER) (1.62) were obtained in fish fed diet containing 0.34 g 100 g^?1 tryptophan. However, quadratic regression analysis of weight gain, FCR, PER and body protein deposition (BPD) data indicated requirements for dietary tryptophan at 0.37, 0.33, 0.32 and 0.33 g 100 g^?1 of dry diet, respectively. Significantly (P < 0.05) higher body protein, minimum moisture and intermediate fat contents were recorded at 0.34 g 100 g^?1 dietary tryptophan diet. Ash content was not significantly different (P > 0.05) among treatments except for diets 0.04 and 0.14 g 100 g^?1. Excellent somatic and haematological indices values were obtained at the requirement level. Based on above results, it is recommended that the diet for H. fossilis should contain tryptophan at 0.32 g 100 g^?1, dry diet, corresponding to 0.80 g 100 g^?1 dietary protein for optimum growth and efficient feed utilization.     

Quantifying the dietary niacin requirement of the Indian catfish, Heteropneustes fossilis (Bloch), fingerlings

A growth study was conducted to determine the dietary niacin requirement of the Indian catfish, Heteropneustes fossilis (Bloch), fingerlings (Mean weight 9.41 ± 0.18 g). Semi‐purified diets with five levels (0, 5, 10, 20 and 40 mg kg^?1 diet) of supplemental niacin were fed to H. fossilis for 15 weeks. Each diet was fed to three replicate groups of fish. Results indicated that the highest (P < 0.05) weight gain was for the fish fed the diet supplemented with 20 mg niacin kg^?1, followed by fish fed the diets with 40, 10 and 5 mg niacin kg^?1, and the lowest in fish fed the unsupplemented control diet. Patterns of specific growth rate (SGR) and protein efficiency ratio (PER) were similar to those of the weight gain. Survival of fish fed the control diet and niacin‐supplemented diet was 58% and 91–100% respectively. Niacin deficiency signs such as anaemia, anorexia, lethargy and skin haemorrhage were observed in fish fed the control diet. The haematocrit values (Ht) were higher (P < 0.05) in fish fed the diets supplemented with niacin than in fish fed the control diet. The hepatosomatic indexes (HSI) of fish fed with or without niacin‐supplemented diets were not significantly (P > 0.05) different from each other. Both body protein and lipid content were higher (P < 0.05) in fish fed the diet supplemented with 20 and 40 mg niacin kg^?1, respectively, than those fish fed other diets. The niacin content in liver significantly (P < 0.05) reflected the supplementation level in the diet and ranged from 29.11 to 40.31 mg g^?1 tissue. The associated liver niacin content for growth was about 47 μg g^?1 tissue. Quadratic regression analysis showed that the dietary niacin requirement for maximal growth of H. fossilis under these experimental conditions was about 25 mg kg^?1 diet.     

Dietary rutin has limited synergistic effects on vitamin C nutrition of fingerling channel catfish (Ictalurus punctatus)

A study was conducted to determine the possible synergistic effects between dietary rutin (a bioflavonoid) and vitamin C, and to evaluate their antioxidant effects in fingerling channel catfish. Purified casein/gelatin diets containing two levels of rutin (0 and 1000 mg/kg diet) and three levels of L-ascorbic acid (0, 1500 and 3000 mg/kg diet) in a factorial arrangement were fed to fingerling channel catfish for 16 weeks. Fish fed the diets without supplemental vitamin C showed deformed spinal columns, external hemorrhages and fin erosion after 10 to 12 weeks. Also these fish had significantly (p < 0.05) depressed body weight gain, feed efficiency, hematocrit, hepatosomatic index (% liver weight), as well as reduced liver, fillet and plasma vitamin concentrations after 16 weeks. Liver, fillet and plasma vitamin C concentrations were correlated with dietary vitamin C levels. Forced oxidation of fillet samples significantly (p < 0.05) increased 2-thiobarbituric acid (TBA) values of fillets from fish fed diets without vitamin C and rutin. However, results from the present study indicated only limited synergistic effects of dietary rutin on vitamin C nutrition of channel catfish.     

A study on dietary l‐lysine requirement of juvenile yellow catfish Pelteobagrus fulvidraco

An 8‐week feeding trial was conducted to determine lysine requirement of juvenile yellow catfish (Pelteobagrus fulvidraco) by feeding formulated diets containing crystalline l ‐lysine. Six isonitrogenous and isoenergetic diets (405 g kg^?1 protein, 18 kJ g^?1 gloss energy) containing fish meal together with soybean protein concentrate as protein sources and fish oil together with soybean oil as lipid sources were formulated. Crystalline l ‐lysine was added into the six diets to acquire lysine concentrations of 17.3, 21.8, 26.0, 31.3, 35.5 and 41.9 g kg^?1 dry diets, respectively. Mixture of crystalline amino acid was supplemented to simulate the amino acid profile in muscle of yellow catfish. The results indicated that final body weight (FBW), weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency (PE) increased with the increase in dietary lysine level from 17.3 to 31.3 g kg^?1 of diet and then decreased as the dietary lysine levels further increased. No significant difference in survival rate was found among all the dietary treatments. One‐slope, quadratic broken‐line analysis on the basis of SGR showed that the dietary l ‐lysine requirement of juvenile yellow catfish was 33.1 g kg^?1 of dry diet (83.2 g kg^?1 of dietary protein).     

Dietary biotin requirement of fingerling Channa punctatus (Bloch)

ABSTRACT

Dietary biotin requirement of fingerling Channa punctatus (4.52 ± 0.46 g) was estimated by conducting a 16-week growth trial. Fish were fed casein gelatin-based purified diets (450 g/kg crude protein, 18.39 kJ/g gross energy) with seven levels of dietary biotin (0, 0.04, 0.09, 0.47, 1.02, 1.43, and 1.96 mg/kg diet) to triplicate groups near to satiation. Significantly higher absolute weight gain (P = 0.0018), specific growth rate (P = 0.0027), protein gain (P = 0.0016), protein deposition (P = 0.0038), and lower feed conversion ratio (P = 0.0003) were shown in fish fed diet containing 0.47 mg/kg biotin, whereas liver biotin concentration showed a significant improvement (P = 0.0021) with increasing levels of dietary biotin up to 1.02 mg/kg. Broken-line analysis of absolute weight gain, protein gain, and liver biotin concentrations indicated that fingerling C. punctatus require biotin at 0.46, 0.44, and 0.97 mg/kg diet. Based on protein gain, optimum pyridoxine requirement for fingerling C. punctatus is recommended at 0.44 mg/kg diet.     

斑点叉尾鮰病毒性疾病综述

综述了斑点叉尾鮰病毒病的流行情况、临床症状,论述了影响疾病爆发的因子、诊断、治疗、控制和预防措施。     

Nutriphysiological and cytological responses of juvenile channel catfish (Ictalurus punctatus) to dietary oxidized fish oil

An 86‐day growth trial was conducted to investigate the effect of dietary oxidized fish oil on the growth and cytopathology of juvenile channel catfish (Ictalurus punctatus). Four diets containing 0 g kg^?1 (control: fresh fish oil), 30 g kg^?1 (low‐oxidized oil group), 60 g kg^?1 (medium‐oxidized oil group) and 90 g kg^?1 (high‐oxidized oil group) graded oxidized oil levels with the same dietary lipid level (90 g kg^?1 diet) were evaluated. The results show that the specific growth rate decreased with increasing dietary oxidized oil level (P < 0.05). All examined liver and kidney tissues in all dose groups exhibited what appeared as dose‐dependent cellular modifications. In addition, lipid droplet accumulation in the hepatocytes of fish in all dose groups was increased, and their localizations were distinctly different between all dose groups. The ultrastructural changes suggest the progression of mitochondrial vacuolation, especially in the renal tubules, in all dose groups. These results reveal a previously underappreciated effect of dietary oxidized fish oil on channel catfish kidneys. Overall, a series of nutriphysiological responses were adversely affected by exposure to dietary oxidized fish oil, and the corresponding interference patterns on the metabolism and transport of nutrients within cells were observed.     

Growth,feed conversion and body composition of fingerling stinging catfish Heteropneustes fossilis (Bloch) fed varying levels of dietary l‐threonine

An 8‐week feeding trial was conducted to assess the effects of dietary l ‐threonine on growth, protein utilization, threonine retention efficiencies, nucleic acid indices and body composition of fingerling Heteropneustes fossilis (6.6 ± 0.1 g; 10.9 ± 0.2 cm). Casein–gelatin based isonitrogenous (38% crude protein; CP) and isocaloric (15.3 kJ g^?1 digestible energy; DE) amino acid test diets with six levels of dietary l ‐threonine (0.75%; 1.0%; 1.25%; 1.5%; 1.75%; 2.0% dry diet) were prepared and hand‐fed to quadruplicate groups of fingerling to apparent visual satiation twice daily. Weight gain (WG; 46.3 g fish^?1), feed conversion ratio (FCR; 1.98), protein utilization efficiency (PUE; 0.25), threonine retention efficiency (TRE; 0.69), lipid productive value (LPV; 0.45), body protein (18.2%) and RNA/DNA ratio (3.6) of fish fed graded levels of dietary threonine increased significantly (P < 0.05) up to 1.49% threonine of dry diet. To generate precise information, the WG, RNA/DNA and LPV data were subjected to broken‐line and quadratic regression analyses. The two models were superimposed and requirement was determined by establishing the point, where the quadratic curve first intersected the plateau of broken‐line. Based on the above mathematical analyses, optimum dietary threonine requirement of fingerling H. fossilis was estimated to range between 1.62% and 1.69% of the diet, corresponding to 4.26–4.44% protein.     

Dietary l‐lysine requirement of fingerling stinging catfish,Heteropneustes fossilis (Bloch) for optimizing growth,feed conversion,protein and lysine deposition

Dietary lysine requirement of fingerling Heteropneustes fossilis (6.96 ± 0.05 g) was quantified by conducting 12‐week feeding trial in a flow‐through system at 28°C. Casein–gelatin based isonitrogenous (38% CP) and isocaloric (14.7 kJ g^?1 DE) amino acid test diets with six levels of dietary lysine (1.5%, 1.75%, 2.0%, 2.25%, 2.5%, 3.0% dry diet) were fed to apparent satiation in triplicates. Broken‐line and second‐degree polynomial regression analyses at 95% plateau of absolute weight gain (AWG; g fish^?1), feed conversion ratio (FCR), protein deposition (PD; g fish^?1) and lysine deposition (LD; g fish^?1) exhibited lysine requirement between 2.0% to 2.3% of the dry diet, corresponding to 5.3–6.1% protein.     

Susceptibility of channel catfish (Ictalurus punctatus) fed with dietary sodium chloride to nitrite toxicity

Juvenile channel catfish (Ictalurus punctatus) were fed with nutritionally complete, basal diets supplemented with NaCl at 0, 10, 20 or 40 g kg^?1 diet (0, 1, 2, or 4%) to apparent satiation twice daily for 10 weeks. Catfish were exposed to nitrite after six (7.70 mg L^?1 nitrite‐N) and ten (7.18 mg L^?1 nitrite‐N) weeks of feeding to determine the effect of dietary NaCl supplementation on resistance to nitrite toxicity. Fish were sampled before (baseline, pre‐exposure) and after 24‐h nitrite exposure to determine the effects of dietary NaCl on haematology (haematocrit, haemoglobin and methaemoglobin) and plasma electrolyte dynamics (nitrite, chloride, sodium and potassium). Mortality from nitrite toxicity was also determined. Mortality from nitrite exposure tended to decrease with increasing NaCl in the diet at 6 weeks and was significantly lower in the 40 g kg^?1 NaCl group (12.5%) compared to the control group (57.5%). A similar trend in mortality occurred at 10 weeks as well; however, the differences among dietary treatments were not significant. The improvements in blood MetHb (non‐significant), chloride and nitrite levels in catfish may at least in part be responsible for the improved survival after nitrite exposure, which trended in support of the prevailing hypotheses for the positive effects of NaCl on nitrite toxicity.