Search

The dietary cyanocobalamin requirement of fingerling Catla catla (3.2 ± 0.13g; 7.2 ± 0.23 cm) was evaluated by feeding casein–gelatin‐based isonitrogenous (350 g/kg crude protein) and isocaloric (16.72 kJ/g GE) diets. Triplicate groups of fish were fed diets containing different concentrations of cyanocobalamin (0, 0.01, 0.02, 0.04, 0.08, 0.16 and 0.32 mg/kg) to apparent satiation at 07:00, 12:00 and 17:30 hr for 16 weeks. Maximum absolute weight gain (AWG; 28.9 g/fish), specific growth rate (SGR; 2.01%), best feed conversion ratio (FCR; 1.57), protein retention efficiency (PRE; 30.8%) and highest protein gain (PG; 4.8 g/fish) were recorded in fish fed diet containing 0.04 mg cyanocobalamin per kg. Whole body protein and haematological parameters increased significantly (p <.05) as dietary cyanocobalamin levels increased from 0 to 0.04 mg/kg, and thereafter remained unaffected with further inclusion of cyanocobalamin. Antioxidant and immune parameters increased with increasing concentration of dietary cyanocobalamin up to 0.04 mg/kg diet. Liver cyanocobalamin concentrations increased linearly (p <.05) with the incremental levels of dietary cyanocobalamin. Based on broken‐line regression analysis of AWG, PRE, SOD, ALP and TSP activities of fingerling C. catla, the dietary cyanocobalamin requirement ranging between 0.034 and 0.037 mg cyanocobalamin per kg diet is recommended. [ABSTRACT FROM AUTHOR]

Isoleucine requirement of fingerling Channa punctatus (6.74 ± 0.09 g) was estimated by feeding seven trial diets (450 g/kg CP, 14.73 kJ/g DE) containing 3.8, 7.5, 11.3, 15.1, 19.3, 23.2 and 27.4 g/kg of isoleucine for 12 weeks. Growth and haematological parameters increased with the increasing concentrations of dietary isoleucine up to 16 g/kg. Carcass protein and fat increased significantly with the increasing concentrations of dietary isoleucine up to 16 g/kg and then stabilized. Moisture content showed reverse trend to that of carcass fat. Hepatosomatic index was found to be highest at 4 g/kg of dietary isoleucine. Viscerosomatic index and condition factor increased significantly with increasing levels of isoleucine up to 16 g/kg dry diet. Serum protein, lysozyme and superoxide dismutase activities were also found to increase significantly up to 16 g/kg dry diet. Significant reduction in alanine aminotransferase and aspartate aminotransferase activities was observed by increasing concentrations of dietary isoleucine up to 16 g/kg. Based on quadratic regression analysis of absolute weight gain, feed conversion ratio, protein retention and isoleucine retention efficiencies against varying concentrations of isoleucine, the optimum isoleucine requirement ranging between 17.95 and 18.39 g/kg dry diet, corresponding to 39.88–40.86 g/kg dietary protein, is recommended for maximizing growth of C. punctatus. [ABSTRACT FROM AUTHOR]

Dietary copper requirement of Heteropneustes fossilis (6.74 ± 0.03 g) was determined by feeding purified diets containing same protein (400 g/kg) and gross energy (17.89 kJ/g) but different levels of copper for 12 weeks. Graded amount of CuSO4.5H2O (0, 1.96, 3.93, 5.89, 7.86, 9.82, 11.79 mg/kg) was supplemented to basal diet to attain desired dietary copper levels (0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mg/kg). Analysed dietary copper concentrations were 4.28, 4.63, 5.28, 5.70, 6.19 and 6.69 mg/kg. Absolute weight gain, feed conversion ratio and protein gain improved with the increasing levels of dietary copper up to 5.28 mg/kg. Further inclusion of copper at a level of 5.70 mg/kg did not improve the above parameters. Significantly higher (p <.05) plasma ceruloplasmin, liver copper‐zinc superoxide dismutase, catalase activities and lower thiobarbituric acid reactive substances were evident in fish receiving diets with 5.28 and 5.70 mg/kg copper compared to other groups. Whole body and liver copper concentrations increased significantly (p <.05) with increasing dietary copper levels. Quadratic regression analysis of absolute weight gain, feed conversion ratio, protein gain and broken‐line regression analysis of plasma ceruloplasmin activity and liver TBARS value against the variable dietary copper levels depicted the dietary copper requirements for fingerling H. fossilis in the range of 5.24–5.68 mg/kg. [ABSTRACT FROM AUTHOR]

To quantify the dietary potassium requirement of fingerling Labeo rohita (6.2 ± 0.12 cm; 1.98 ± 0.06 g), seven purified experimental diets (350 g/kg crude protein and 16.72 kJ/g gross energy) with graded levels of potassium (0.32, 1.35, 2.41, 3.46, 6.48, 9.47 and 12.39 g/kg diet) were fed to triplicate groups of fishes at 08:00, 12:00 and 16:00 hr to apparent satiation for 8 weeks. Live weight gain (LWG; 671.46%), specific growth rate (3.65%/day), protein efficiency ratio (2.16), protein gain (PG; 2.41 g/fish) and feed conversion ratio (1.32) were found to be best in fish fed diet containing 3.46 g/kg potassium. Gill Na+‐K+ ATPase activity was also highest in fish fed diet with 3.46 g/kg potassium. Potassium content of whole‐body, vertebrae and scales increased significantly with the increase in dietary potassium level up to 6.48 g/kg. Significant changes were also noted in serum malondialdehyde content, superoxide dismutase, catalase, glutathione peroxidase and alkaline phosphatase activity. Based on the maximum live weight and protein gain observed in the present study, the inclusion of 3.55 g/kg potassium is recommended for developing potassium‐balanced commercial feeds for intensive culture of fingerling L. rohita. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein-gelatin-based diets (400 g kg−1 CP; 18.69 kJ g−1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg−1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg−1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg−1 diet. Broken-line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79-3.34 mg kg−1 diet (0.096-0.179 μg thiamin kJ−1 gross energy). In experiment II, six casein-gelatin-based diets (400 g kg−1 CP; 18.69 kJ g−1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg−1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg−1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg−1 dietary pyridoxine. Broken-line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg−1 diet. Data generated during this study would be useful in formulating thiamin- and pyridoxine-balanced feeds for the intensive culture of this fish. [ABSTRACT FROM AUTHOR]

A 12-week feeding trial was conducted to estimate the dietary copper requirement of fingerling Channa punctatus. Six casein−gelatin-based test diets (450 g kg−1 crude protein; 18.81 kJ g−1 gross energy) with graded levels of copper as copper sulphate (3.7, 4.7, 5.7, 6.7, 7.7 and 8.7 mg copper equivalent kg−1 diet) were formulated and fed to triplicate groups of fish (7.25 ± 0.81 cm; 5.21 ± 0.27 g) near to satiation. Fish fed diet with 6.7 mg kg−1 copper had highest absolute weight gain ( AWG; 51.63 g fish−1), protein efficiency ratio ( PER; 1.42 g fish−1), protein gain ( PG; 8.34 g fish−1), haemoglobin (Hb; 9.68 g dL−1), haematocrit (Hct; 31.18%) and RBCs (3.24 × 106 × mm−3). Feed conversion ratio ( FCR) was found to be best (1.57) at above level of dietary copper. Whole body copper concentration was found to increase with the increasing levels of dietary copper. Hepatic thiobarbituric acid-reactive substances concentration was found to decrease with increasing dietary concentrations of copper up to 6.7 mg kg−1 beyond which a reverse trend in this parameter was noted. Broken-line regression analysis of AWG, FCR and PG concentrations against varying levels of dietary copper yielded the requirement in the range of 6.66-6.78 mg kg−1. Data generated during this study would be useful in formulating copper-balanced commercial feeds for the intensive culture of this fish. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

To investigate the histidine requirement of fingerling Catla catla (3.65 ± 0.15 cm; 0.65 ± 0.36 g), six casein-gelatin based diets (33% CP; 13.58 kJ g−1 DE) containing graded levels of L-histidine (0.25%, 0.39%, 0.53%, 0.67%, 0.83%, 0.96% of the dry diet) were fed near to satiation thrice a day for 12 weeks. Maximum absolute weight gain (AWG; 8.63 g fish−1), protein gain (PG; 1.45 g fish−1), histidine gain (HG, 48.19 mg fish−1), RNA/DNA ratio (4.15), best feed conversion ratio (FCR; 1.31), highest haemoglobin (Hb, 9.61 g dL−1), RBCs (2.84 × 106 mm−3) and haematocrit (Ht, 30.12%) were recorded in fish fed diet containing 0.67% histidine. However, broken-line regression analysis of AWG, PG, HG, RNA/DNA ratio, FCR, Hb, Ht and RBCs against dietary histidine reflected the histidine requirement at 0.65%, 0.64%, 0.63%, 0.68%, 0.63%, 0.66%, 0.68% and 0.65% dry diet respectively. Carcass protein was found to improve significantly ( P < 0.05) from 13.36% to 16.42% with the increase in dietary histidine from 0.25% to 0.67%. Based on regression analysis of AWG, PG, HG, RNA/DNA ratio, FCR, Hb, Ht and RBCs, it is recommended that the diet for fingerling catla should contain histidine in the range of 0.63-0.68% dry diet, equivalent to 1.91-2.06% of the dietary protein for optimum growth, feed utilization, blood profile and carcass composition. [ABSTRACT FROM AUTHOR]

Two separate 12 weeks feeding trials were performed to quantify the total sulphur amino acid (TSAA) requirement (experiment I) and cysteine replacement value for methionine (experiment II) of fingerling Catla catla. In experiment I, six casein-gelatin based (33% crude protein; 16.72 kJ g-1 gross energy) diets with graded levels of TSAA (0.56%, 0.81%, 1.06%, 1.31%, 1.56%, 1.81% dry diet) were fed to triplicate groups of fish (3.55 ± 0.06 cm; 0.65 ± 0.02 g) near to satiation. The TSAA requirement was determined by quadratic regression analysis of absolute weight gain (AWG), protein efficiency ratio (PER), feed efficiency (FE), protein gain (PG) and TSAA gain (TSAAG) against dietary TSAA concentrations at 95% maximum response. Above analysis revealed that inclusion of TSAA at 1.28% dry diet (1.22% methionine + 0.06% cysteine), corresponding to 3.87% of dietary protein is optimum. In experiment II, to determine the replacement value of cysteine for methionine, six diets containing 1.28% TSAA determined in experiment I with different ratios of L-methionine and L-cysteine (80:20, 70:30, 60:40, 50:50, 40:60, 30:70) on equimolar sulphur basis were fed to fish (3.65 ± 0.08 cm; 0.67 ± 0.04 g). Broken-line regression analysis of AWG, PER, FE, PG and TSAAG against varying methionine to cysteine ratios yielded the optimum cysteine replacement value at 40.3%. Based on above analysis, it is recommended that inclusion of 1.28% dietary TSAA, corresponding to 3.87% of dietary protein is optimum of which 40.3% could be spared by cysteine. Data generated during this study would be useful in formulating TSAA balanced, cost-effective feeds for the intensive culture of this fish. [ABSTRACT FROM AUTHOR]

A 12-week feeding trial was conducted to determine the dietary threonine requirement of fingerling Indian major carp, Catla catla (3.35 ± 0.11 cm; 0.59 ± 0.06 g). Six casein-gelatin based (33% crude protein; 3.23 kcal g-1 digestible energy) amino acid test diets with graded levels of analysed threonine (0.74%, 0.96%, 1.21%, 1.48%, 1.72% and 1.93% dry diet) were fed to satiation to triplicate groups of fish. Absolute weight gain (g per fish), feed conversion ratio, protein retention efficiency, threonine deposition, RNA/DNA ratio and carcass protein significantly improved with the increase in dietary threonine and peaked at 1.48% of the dry diet. Haematological indices were also found to be best in fish fed at 1.48% threonine diet. Quadratic regression analysis of absolute weight gain, feed conversion ratio, protein retention efficiency, threonine deposition, RNA/DNA ratio, carcass protein, haemoglobin (g dL-1), haematocrit (%) and RBCs (106 × mm-3) at 95% of maximum and minimum response exhibited the threonine requirement of fingerling C. catla between 1.35% and 1.48% dry diet, corresponding to 4.09-4.48% dietary protein. Present finding would be useful in formulating threonine-balanced feeds for the intensive culture of C. catla. [ABSTRACT FROM AUTHOR]

Amino acids are vital for all living organisms including fish and histidine is an essential amino acid for fish. In view of this, dietary histidine requirement of fry Heteropneustes fossilis was determined by feeding casein-gelatin-based isonitrogenous (430 g kg−1 CP) and isocaloric (17.9 MJ kg−1 GE; 15.5 MJ kg−1 DE) amino acid test diets (10 to 20 g histidine kg−1 dry diet) to quadruplicate groups of randomly assigned fish to apparent satiety for 12 weeks. Maximum absolute weight gain (AWG; 44 g fish−1), protein retention efficiency (PRE; 20%), protein efficiency ratio (PER; 1.04), haemoglobin (Hb; 11.24 g dL−1), haematocrit (Hct; 35.11%), red blood count (RBCs; 2.98 × 109 mL−1) and lowest erythrocyte sedimentation rate (ESR; 1.92 mm h−1) were obtained at 16 g histidine kg−1 dry diet. The 95% maximum quadratic response of above data exhibited the requirement to be at 15.2, 15.1, 15.6 and 15.5 g histidine kg−1 diet. As histidine is found in higher concentration in haemoglobin, requirement obtained for Hct% and Hb is 4% greater than that required for maximizing weight gain and protein retention. Based on these results, dietary histidine requirement of H. fossilis fry is recommended between 15.1 and 15.6 g kg−1, corresponding to 35.1-36.3 g kg−1 protein. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

The effects of feeding rates on growth, feed conversion, protein deposition and carcass quality of fingerling Catla catla (3.61 ± 0.03 cm; 0.71 ± 0.04 g) were worked out by conducting a 16-week feeding trial. Fingerlings were fed with a casein-gelatin-based purified diet (40% crude protein CP; 14.95 MJ kg−1 digestible energy; DE) at 1%, 2%, 3%, 4%, 5%, 6% and 7% body weight per day. The absolute weight gain ( AWG; 10.50 g fish−1) and feed conversion ratio ( FCR; 1.41) were highest at the feeding rate of 5% body weight per day. However, protein gain ( PG; 0.36 g fish−1) and carcass protein content attained the maximum values at 4% BW day−1. Quadratic regression analyses of AWG g fish−1 and PG g fish−1 at 95% maximum response indicated that these parameters attained the best values at 4.19% and 3.81% BW day−1. On the basis of the above results it is recommended that the feeding rate in the range of 3.81-4.19% BW day−1 with a P:E ratio of 26.69-27.74 mg protein MJ−1 DE is optimum for maximum growth, efficient feed conversion and best carcass quality in fingerling C. catla. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study was aimed at quantifying methionine requirement of Indian major carp fry, C irrhinus mrigala (2.2 ± 0.2 cm; 0.19 ± 0.02 g) by conducting a 12-week feeding trial. Casein-gelatine-based isonitrogenous (40 g 100 g−1 crude protein) and isoenergetic (15.42 kJ g−1 DE) amino acid test diets were prepared to contain six levels of l-methionine (1.1, 1.3, 1.5, 1.7, 1.9 and 2.1 g 100 g−1 dry diet) at a fixed level of cysteine (0.85 g 100 g−1 dry diet) and fed to apparent satiation thrice daily to triplicate groups of fish. When absolute weight gain (g per fish), feed conversion ratio, protein deposition (g per fish) and nitrogen retention efficiency data were subjected to broken-line and second-degree polynomial regression analysis, 95% of the plateau of above parameters was achieved at dietary methionine concentrations between 1.60 and 1.69 g 100 g−1 dry diet or 0.10 to 0.11 g methionine kJ−1 DE, corresponding to 4.1-4.22 g 100 g−1 protein or 0.44-0.47 g methionine kJ−1 DE. Based on these results, dietary methionine requirement of fry C . mrigala is recommended 1.60-1.69 g 100 g−1 diet or 0.10-0.11 g methionine kJ−1 DE. [ABSTRACT FROM AUTHOR]

The effect of feeding graded levels of vitamin E (E0, E20, E40, E60, E100, E140, E180, E220, E260) in nine casein-gelatin-based isonitrogenous (450 g kg−1 crude protein) and isoenergetic (17.97 kJ g−1 gross energy) experimental diets was evaluated in fingerling Channa punctatus for 12 weeks. Growth, nutritional and haematological parameters were studied. Hepatic lipid peroxidation as thiobarbituric acid-reactive substances (TBARS) was also assayed. The maximum absolute weight gain (AWG g/fish, 55), best feed conversion ratio (FCR, 1.32), protein retention efficiency (PRE, 40%) and energy retention efficiency (ERE, 76%) were achieved in fish fed on a diet supplemented with 140 mg vitamin E kg−1 diet (E140). A consistent decline in the hepatic TBARS concentration and an improvement in haematocrit (Hct) and haemoglobin (Hb) were displayed in fish fed on diets with increasing concentrations of vitamin E up to 140 mg kg−1 (E0-E140), beyond which (E180-E260) a reverse trend in these parameters was evident. Based on the broken-line regression and exponential analyses of AWG, FCR, PRE, ERE, Hb and Hct data, diets for fingerling C. punctatus should contain vitamin E in the range of 140-169 mg kg−1 to maintain satisfactory fish performance. [ABSTRACT FROM AUTHOR]

Dietary histidine requirement of fry African catfish, Clarias gariepinus (2.57 ± 0.02 cm; 0.22 ± 0.03 g) was quantified by feeding casein–gelatin-based isonitrogenous (40% crude protein) and isocaloric (17.90 kJ g−1 gross energy) amino acid test diets with graded levels of histidine (0.25%, 0.30%, 0.35%, 0.40%, 0.45% and 0.50% dry diet) in eighteen 80 L indoor circular aqua-coloured troughs provided with the flow-through system for 12 weeks. Maximum absolute weight gain (2.66), best feed conversion ratio (1.29), highest protein efficiency ratio (1.94), protein retention efficiency (34%) and energy retention efficiency (70.4%) were achieved at 0.40% dietary histidine. Broken-line and non-linear regression models were adopted to assess dietary histidine requirement for C. gariepinus. When analysed using broken-line regression model these parameters were also best at 0.40% dietary histidine corresponding to 1.0% protein, respectively, whereas using second-degree polynomial regression analysis, histidine requirement was obtained at 0.42%, 0.41%, 0.40%, 0.41% and 0.41% of dry diet, corresponding to 1.05%, 1.02%, 1.0%, 1.02% and 1.02% protein respectively. Based on the broken-line and second-degree polynomial regression analyses of the growth and nutrient retention data, optimum histidine requirement of fry C. gariepinus was found to be in the range of 0.40–0.42% dry diet, corresponding to 1.0–1.05% of dietary protein. [ABSTRACT FROM AUTHOR]

An 8-week feeding experiment was conducted in a water flow-through system (26–28 °C) to determine the dietary threonine requirement of fingerling Labeo rohita (3.90±0.03 cm; 0.58±0.02 g). Growth, feed utilization and body composition of fish fed test diets (40% crude protein; 17.9 kJ g−1 gross energy) with graded levels ofl-threonine (0.75%, 1.0%, 1.25%, 1.50%, 1.75% and 2.0% dry diet) to apparent satiation were response variables used to assess threonine adequacy. Diets were made isonitrogenous and isoenergetic by adjusting the levels of glycine and dextrin. The amino acid profiles of the test diets were formulated to that of 40% whole chicken egg protein except for threonine. The performance of fish fed experimental diets was evaluated using calculated values for weight gain (g fish−1), feed conversion ratio (FCR), protein efficiency ratio (PER) and protein productive value (PPV) data. Maximum weight gain (g fish−1) (1.79), lowest FCR (1.39), highest PER (1.76) and PPV (0.33) were recorded at 1.50 g per 100 g dietary threonine. Statistical analysis of weight gain, FCR, PER and PPV data reflected significant differences ( P<0.05) among treatments. Except for reduced growth performance in fish fed threonine-deficient diets, no deficiency signs were noted. Weight gain, FCR, PER and PPV data were also analysed using second-degree polynomial regression analysis to obtain a more accurate threonine requirement estimate, which was found, using each response variable, to be at 1.70, 1.63, 1.65 and 1.51 g per 100 g of dry diet, corresponding to 4.2, 4.07, 4.12 and 3.77 g per 100 g of dietary protein respectively. Based on the second-degree polynomial regression analysis of the live weight gain, FCR, PER and PPV data, the optimum dietary level of threonine for fingerling L. rohita was found to be in the range of 1.51–1.70 g per 100 g of the dry diet, corresponding to 3.77–4.2 g per 100 g of dietary protein. [ABSTRACT FROM AUTHOR]

An 8-week feeding experiment was conducted to quantify the dietary isoleucine requirement of fingerling Indian major carp, Labeo rohita (3.50 ± 0.04 cm; 0.40 ± 0.02 g) using amino acid test diets (400 g kg−1 crude protein; 17.90 kJ g−1 gross energy) containing casein, gelatin andl-crystalline amino acids. Six dietary treatments supplemented with graded levels of isoleucine (7.5, 10.0, 12.5, 15.0, 17.5 and 20.0 g kg−1), in gradations of 2.5 g kg−1 diet, were fed to triplicate groups of fingerlings to apparent satiation divided over two feedings at 07:00 and 17:30 h. Performance of the fish was evaluated on the basis of live weight gain, feed conversion ratio (FCR), protein efficiency ratio (PER), specific growth rate (SGR) and protein productive value (PPV). Statistical analysis of live weight gain, FCR, PER, SGR and PPV reflected significant differences among treatments. Live weight gain and conversion efficiencies were best with isoleucine at 15.0 g kg−1 of diet. Live weight gain, FCR, PER, SGR and PPV data were also analysed using second-degree polynomial regression analysis to obtain more accurate isoleucine requirement estimate which was found to be at 15.9, 15.3, 15.2, 15.8 and 15.7 g kg−1 of dry diet, corresponding to 39.8, 38.3, 38.0, 39.5 and 39.3 g kg−1 of dietary protein respectively. Based on the quadratic regression analysis of the live weight gain, FCR, PER, SGR and PPV, the optimum level of isoleucine for fingerling L. rohita is in the range of 15.2–15.9 g kg−1 of dry diet, corresponding to 38.0–39.8 g kg−1 of dietary protein. Maximum body protein, minimum moisture and fat were noted at 15.0 g kg−1 of dietary isoleucine while the body ash remained constant among all the treatment levels. No mortality was recorded during the duration of the experiment. [ABSTRACT FROM AUTHOR]

The dietary arginine requirement of fingerling hybrid Clarias ( Clarias gariepinus× Clarias macrocephalus) (4.2±0.03 cm, 0.56±0.04 g) was determined by feeding six isonitrogenous (400 g kg−1 crude protein) and isocaloric (17.9 kJ g−1) amino acid test diets containing casein, gelatin andl-crystalline amino acids with graded levels of arginine (10.0, 12.5, 15.0, 17.5, 20.0 and 22.5 g kg−1) for 4 weeks to triplicate groups. Diets were fed twice a day at 09:00 and 16:00 hours at 8% body weight day−1. Maximum weight gain (523%), best feed conversion ratio (FCR, 1.41), protein efficiency ratio (1.78) and specific growth rate (6.53%) were recorded in fish fed the diet containing arginine at 20.0gkg−1 of the diet. Second-degree polynomial regression analysis of live weight gain and FCR values indicated the dietary arginine requirement at 17.8 and 20.0 g kg−1 of dry diet respectively. Significantly higher carcass protein and protein deposition values were recorded at the requirement level (20.0 g kg−1). Higher fat and lower moisture values were obtained in carcass of fish fed the diet with 15.0g kg−1 arginine. The maximum carcass ash value was noticed in the fish fed at 20.0 g kg−1 dietary arginine. We recommend that the diet for hybrid Clarias ( C. gariepinus× C. macrocephalus) should contain arginine in the range of 17.8–20.0 g kg−1 of the dry diet, corresponding to 44.5 and 50 g kg−1 of dietary protein respectively. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was conducted to evaluate the effects of dietary tryptophan concentration on weight gain and feed efficiencies of fingerling Indian major carp,Cirrhinus mrigala. Six isonitrogenous (40% crude protein) and isocaloric (17.90 kJ g−1) amino acid test diets containing casein, gelatin andl-crystalline amino acids with graded levels ofl-tryptophan (0.06, 0.16, 0.26, 0.36, 0.46 and 0.56 g 100 g−1 dry diet) were formulated. Fish (4.25±0.30 cm, 0.62±0.02 g) were randomly stocked in triplicate groups in 70 L (water volume 55 L) flow-through (1–1.5 L min−1) indoor circular tanks and fed experimental diets at 5% of their body weight/day in two feedings at 08:00 and 16:00 hours. Maximum live weight gain (277%), lowest feed conversion ratio (FCR) (1.50) and highest protein efficiency ratio (PER) (1.66) were measured at 0.36% dietary tryptophan. The relationship between dietary tryptophan levels and weight gain, FCR and PER data were described using second-degree polynomial regression analysis indicating the tryptophan requirement at 0.42, 0.39 and 0.38 g 100 g−1 of dry diet respectively. Whole body moisture decreased with increasing tryptophan up to 0.36%. Significantly (P<0.05) higher protein content was evident in fish fed diet containing 0.36% tryptophan. Body fat increased significantly (P<0.05) in fish fed with different tryptophan concentrations except those fed 0.36% tryptophan where a significantly lower fat content was noted. Significantly (P<0.05) higher ash content was reported at 0.06% and 0.16% tryptophan levels. Survival was 100% in fish fed all the diets except those fed 0.06% tryptophan. Based on the results, diets for fingerlingC.mrigalashould contain tryptophan at 0.38 g 100 g−1 dry diet, corresponding to 0.95 g 100 g−1 dietary protein for optimum growth and efficient feed utilization. [ABSTRACT FROM AUTHOR]