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1.
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).  相似文献   

2.
This study was aimed at quantifying methionine requirement of Indian major carp fry, Cirrhinus 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.  相似文献   

3.
An 8‐week feeding trial was conducted to determine the optimum dietary methionine (Met) requirement of juvenile Pseudobagrus ussuriensis with an initial average weight of 0.60 g reared in indoor flow‐through and aerated aquaria. Six isonitrogenous (430 g kg?1 protein) and isolipidic (50 g kg?1 lipid) test diets were formulated to contain graded levels of crystalline L‐methionine (4.9, 9.0, 11.8, 14.2, 18.1 and 20.8 g kg?1 dry diets, respectively) at a constant dietary cystine level of 2.5 g kg?1 dry diets. Equal amino acid nitrogen was maintained by replacing methionine with non‐essential amino acid mixture. Fish were randomly allotted to 18 aquaria (1.0 × 0.5 × 0.8 m) with 50 fish to each glass aquarium. Fish were fed twice daily (08:00 and 16:00) to apparent satiation. No significant difference was observed in survival of fish (84.67–91.33%). Specific growth rate (SGR), weight gain (WG), feed conversion ratio (FCR), protein productive value (PPV) and protein efficiency ratio (PER) were significantly affected by different dietary methionine levels (P < 0.05). WG, SGR PPV and PER increased, while FCR decreased with increasing dietary methionine level from 4.9 to 11.8 g kg?1 (P < 0.05). However, with further increase from 11.8 to 20.8 g kg?1, WG, SGR PPV and PER significantly decreased, FCR increased (P < 0.05). The whole body and muscle composition were affected by different dietary methionine levels (P < 0.05). Condition factor (CF) increased with increasing dietary methionine levels up to 11.8 g kg?1 (P < 0.05) and after 11.8 g kg?1 methionine diet, but not significant, declines were observed (P > 0.05). Hepatosomatic index (HSI) of the 4.9, 9.0, 11.8 and 14.2 g kg?1 Met diets was significantly higher than that of fish fed diets 18.1 and 20.8 g kg?1 Met diets (P < 0.05). Viscerosomatic index (VSI) of the 4.9, 9.0 and 11.8 g kg?1 Met diets was significantly higher than that of fish fed diets 14.2, 18.1 and 20.8 g kg?1 Met diets (P < 0.05). Quadratic regression analysis of WG and PER against dietary methionine levels indicated that the optimal dietary methionine requirement for maximum growth and feed utilization of juvenile Pseudobagrus ussuriensis was 14.3 and 14.1 g kg?1 dry diet (35.3 and 34.8 g kg?1 dietary protein), respectively, in the presence of 2.5 g kg?1 dry diets cystine.  相似文献   

4.
A growth trial was conducted to examine the effect of dietary digestible energy (DE) content on methionine (Met) utilization and requirement in juvenile Nile tilapia (Oreochromis niloticus). Ten iso‐nitrogenous (288 g kg?1 protein) practical diets, with two DE levels (10.9 MJ kg?1; 12.4 MJ kg?1) and five methionine supplementation levels (0, 1, 2, 4 and 6 g kg?1), were hand‐fed twice daily to triplicate groups of Nile tilapia (initial body weight 8.95 ± 0.06 g) for 8 weeks. Weight gain (WG) and specific growth rate (SGR) increased significantly with increasing dietary methionine concentration at the same DE content (P < 0.001). At the same dietary methionine level, WG and SGR of fish fed high‐DE diets were significantly higher than that of fish fed low‐DE diets (P = 0.0001), although no interaction was found between dietary DE and methionine supplementation. Based on quadratic regression analysis between dietary methionine concentration and weight gain, optimal methionine requirement for maximum growth, expressed as g Met required kg?1 diet (low‐ versus high‐DE diets), increased as diet DE concentration increased (7.34 versus 9.90 g kg?1 diet, respectively; with cysteine 4.70 g kg?1 diet). The results indicated that diet DE content affects methionine utilization and requirement in juvenile Nile tilapia, fish fed high‐DE diets required more methionine for maximum growth.  相似文献   

5.
A total of 630 juvenile Chinese sucker, with an average initial weight of 1.72 ± 0.05 g, were fed seven diets for 56 days to study the effect of dietary methionine levels on growth, feed utilization, body composition and haematological parameters on juvenile Chinese sucker. Diet 1 using fish meal as the sole protein source and diets 2–7 using fish meal and fermented soybean meal as intact protein sources supplemented with crystalline amino acids contained six levels of l ‐methionine ranging from 6.4 to 18.9 g kg?1 of dry diet at a constant dietary cystine level of 3.7 g kg?1. Each diet was randomly assigned to three aquaria. Results indicated that the highest weight gain, specific growth rate (SGR), feed efficiency ratio, protein efficiency ratio and protein productive value occurred at 13.9 g methionine kg?1 diet among the methionine supplemented dietary groups, beyond which they showed declining tendency. The whole body and muscle protein contents of juvenile Chinese sucker were positively correlated with dietary methionine level, while muscle lipid content was negatively correlated with it. The total essential amino acids content of muscle was increased significantly with increasing dietary methionine level from 6.4 to 13.9 g kg?1 (P < 0.05). Apparent digestibility coefficients of dietary protein were significantly affected by dietary treatments. Serum protein, cholesterol and triacylglycerol increased with increasing dietary methionine levels, but showed a relatively lower value for fish fed the 18.9 g methionine kg?1 diet. Quadratic regression analysis of SGR against dietary methionine level indicated that optimal dietary methionine requirement for juvenile Chinese sucker was 14.1 g kg?1 of the diet in the presence of 3.7 g kg?1 cystine (corresponding to 32.0 g kg?1 of dietary protein on a dry‐weight basis).  相似文献   

6.
An 11‐week feeding trial was conducted to evaluate the effect of dietary methionine on the growth, antioxidant status, innate immune response and disease resistance to Aeromonas hydrophila of juvenile yellow catfish. Six isonitrogenous and isolipidic practical diets were formulated to contain different graded methionine levels ranging from 6.1 to 16.4 g kg?1 of dry weight. The results indicated that growth performance and feed utilization were significantly influenced by the dietary methionine levels; fish fed the diet containing 6.1 g kg?1 methionine level had lower specific growth rate, percentage weight gain (PWG), feed efficiency and protein efficiency ratio than those fed the other diets (P < 0.05). Fish fed the diet containing 16.4 g kg?1 methionine level had lowest protein contents in whole body and muscle among all treatments. Triacylglycerols, cholesterol, aspartate aminotransferase, alanine aminotransferase and haemoglobin (Hb) in plasma or whole blood were significantly affected by dietary methionine levels. Fish fed the diet containing 6.1 g kg?1 methionine level had higher superoxide dismutase, glutathione peroxidase activities and malondialdehyde values than those fed other diets. Fish fed diets containing 9.7 and 11.8 g kg?1 methionine levels had higher lysozyme activity, total immune globulin, phagocytic activity and respiratory burst than those fed other diets. The lowest survival after A. hydrophila challenge was observed in fish fed a diet containing 6.1 g kg?1 methionine. Quadratic regression analysis of PWG against dietary methionine levels indicated that the optimal dietary methionine requirement for the maximum growth of juvenile yellow catfish was estimated to be 11.5 g kg?1 of the diet in the presence of 4.0 g kg?1 cystine (corresponding to 23.5 g kg?1 of dietary protein on a dry weight basis).  相似文献   

7.
The experiment was conducted to determine the leucine requirement of juvenile Pacific white shrimp Litopenaeus vannamei (Boone) in low‐salinity water (0.50–1.20 g L?1). Six diets were formulated to contain 410 g kg?1 crude protein with fish meal, peanut meal and precoated crystalline amino acids with different concentration of l ‐leucine (16.72, 19.60, 22.06, 24.79, 27.28 and 30.16 g kg?1 dry diet). Each diet was randomly assigned to triplicate groups of 30 shrimps (0.38 ± 0.002 g), and the feed trial lasted for 8 weeks. The results indicated that the maximum weight gain was observed at 24.95 g kg?1 dietary leucine group, whereas the diets containing higher leucine concentration conversely reduced the growth performance (P < 0.05). Moreover, the highest body protein content and body protein deposition and the lowest haemolymph AST and ALT activities were also found at 24.95 g kg?1 dietary leucine group. With the increase in leucine in diets, a dose‐dependent increase was found in body lipid content and haemolymph urea concentration. The polynomial regression calculated using weight gain, feed efficiency and body protein deposition indicated that the optimal dietary leucine requirement for L. vannamei reared in low‐salinity water was 23.73 g kg?1 leucine of dry diet, correspondingly 57.88 g kg?1 of dietary protein.  相似文献   

8.
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.  相似文献   

9.
This study was conducted to determine dietary thiamine requirement of juvenile Sclizothorax prenanti and evaluate the effect of dietary thiamine levels on growth performance, body composition and haemato‐biochemical parameters for this fish species. The seven experimental diets were formulated to contain the graded levels of thiamine (0, 10, 20, 30, 40, 60 and 100 mg kg?1 diet, respectively), providing the actual dietary thiamine values of 0.31 (control), 9.82, 21.49, 29.83, 41.66, 62.24 and 114.58 mg kg?1 diet, respectively. Each diet was assigned to three replicate groups of S. prenanti (initial body weight: 13.46 ± 0.28 g, means ± SD) for 60 days. Increasing dietary thiamine level up to 21.49 mg kg?1 diet increased weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER) (P < 0.05), beyond which they remained nearly unchanged. Similarly, hepatic thiamine concentration and several serum biochemical parameters (transketolase activity, triglyceride and total cholesterol contents) increased with increasing levels of thiamine up to 21.49 mg kg?1 diet (P < 0.05) and, thereafter, remained almost constant. However, no significant differences in body composition (moisture, protein, lipid and ash contents) were found among dietary thiamine treatments (P > 0.05). Analysis by the broken‐line regression of WGR, SGR, FE, PER, hepatic thiamine concentration and serum transketolase activity indicated that dietary thiamine requirements in juvenile S. prenanti were 18.45–25.91 mg kg?1 diet.  相似文献   

10.
This study compares the effect of food type (formulated diet vs. natural food) and fish size on protein and energy utilization efficiencies for growth in common sole, Solea solea (L.). Replicate groups of common sole (mean initial body weight ± SD was 45.7 g ± 2.1 and 111.2 g ± 4.2) received the diets at five (natural feed) or four (formulated diet) feeding levels. The protein utilization efficiency for growth (kgCP) was higher (P > 0.001) in common sole fed ragworms than in common sole fed the formulated diet (respectively, 0.40 and 0.31). Likewise, the energy utilization efficiency for growth (kgGE) was higher (P = 0.001) in common sole fed ragworms than in common sole fed the formulated diet (respectively, 0.57 and 0.33). The protein maintenance requirement was not different between food types (P = 0.64) or fish size (P = 0.41) being on average 0.82 g kg?0.8 day?1. The energy maintenance requirement was not different between food type (P = 0.390) but differed between fish size (P = 0.036). The gross energy maintenance requirement of small common sole was 35 kJ g?0.8 day?1. The gross energy maintenance requirement of large common sole was 25 kJ g?0.8 day?1. In conclusion, the low growth of common sole fed formulated diets was related to reduced feed utilization.  相似文献   

11.
Two 8‐week growth trials were conducted in indoor recirculation system to evaluate the protein requirements for juvenile (3.70 ± 0.20 g) and pre‐adult (85.2 ± 0.70 g) gibel carp, Carassius auratus gibelio var. CAS III. Six isoenergetic diets were formulated for each trial using fish meal and casein as protein sources, and protein level was 250–450 g kg?1 in Trial 1 and 200–450 g kg?1 in Trial 2. With the increasing dietary protein, feeding rate (FR) and feed conversion ratio (FCR) significantly decreased (P < 0.05). Weight gain (WG) increased first and then reached a plateau in 330–450 g kg?1 in Trial 1 (P > 0.05), while decreased after the maximum value in 350 g kg?1 in Trial 2 (P < 0.05). Productive protein values (PPVs) were lower in 370–450 g kg?1 in Trial 1 and 400–450 g kg?1 in Trial 2 (P < 0.05). Increasing dietary protein level increased protein content and decreased lipid content in whole fish body and white muscle (P < 0.05). Apparent digestibility coefficient of dry matters (ADCd) decreased, while apparent digestibility coefficient of protein (ADCp) increased in 370–450 g kg?1 in Trial 1 and 250–450 g kg?1 in Trial 2 (P < 0.05). Trypsin activity significantly increased in 370–450 g kg?1 in Trial 1 (P < 0.05) and was not affected in Trial 2 (P > 0.05). Hepatic alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities in both trials increased when dietary protein was above 400 g kg?1 (P < 0.05). Based on quadratic regression of WG, it was estimated that dietary protein requirement for maximum growth was 414 g kg?1 (digestible protein of 376 g kg?1) and 365 g kg?1 (digestible protein of 324 g kg?1) for juvenile (3.70 g) and pre‐adult gibel carp (85.2 g).  相似文献   

12.
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.  相似文献   

13.
Dietary arginine requirement of Heteropneustes fossilis fry (3.0 ± 0.5 cm; 5.1 ± 0.3 g) was determined by feeding casein‐gelatin‐based isonitrogenous (400 g kg?1 crude protein) and isocaloric (17.97 kJ g?1) amino acid test diets containing graded levels of l ‐arginine (15, 17, 19, 21, 23 and 25 g kg?1 dry diet) for 12 weeks. Maximum absolute weight gain (AWG) (44.4), best feed conversion ratio (FCR) (1.22), highest protein retention efficiency (PRE%) (41%), energy retention efficiency (ERE%) (75%), best condition factor, hepatosomatic index and viscerosomatic index were noted at 21 g kg?1 arginine of the dry diet. Maximum body protein (189.8 g kg?1) was also obtained in fish fed above diet. Highest haematocrit value (35%), Hb concentration (9.54 g dL?1), RBC count (3.44 × 109 mL?1) and lowest Erythrocyte sedimentation rate (ESR) (1.93 mm h?1) were obtained at the above level of arginine in the diet. AWG, FCR, PRE% and ERE% data were analysed using broken‐line and an exponential fit to obtain more precise dietary arginine requirement. On the basis of broken‐line and exponential analyses of AWG, FCR, PRE and ERE data, inclusion of dietary arginine in the range of 20.4–22.6 g kg?1 dry diet, corresponding to 51–56.5 g kg?1 dietary protein, is recommended for formulating arginine‐balanced feeds for rearing H. fossilis fry.  相似文献   

14.
A 12‐week feeding trial was conducted in eighteen 70 L indoor polyvinyl circular troughs provided with a water flow‐through system (1–1.5 L min?1) at 28 ± 1 °C to evaluate the dietary tryptophan requirement of fingerling Catla catla (3.45 ± 0.24 cm; 0.60 ± 0.13 g). Six casein‐gelatin‐based amino acid test diets (330 g kg?1 crude protein; 13.6 kJ g?1 digestible energy) containing graded levels of L‐tryptophan (1.0, 1.4, 1.9, 2.3, 2.8, 3.4 g kg?1 dry diet) were fed to triplicate groups of fish near to satiation at 08:00, 12:30 and 17:30 h. Absolute weight gain, feed conversion ratio, protein gain, RNA/DNA ratio, hepatosomatic index, viscerosomatic index, condition factor and haematological indices improved with the increasing levels of tryptophan from 1.0 to 2.3 g kg?1 of dry diet. Significantly higher carcass protein was obtained at 2.3 g tryptophan per kilogram of the dry diet. Exponential analysis of absolute weight gain, feed conversion ratio, protein gain and RNA/DNA ratio against dietary tryptophan levels at 95% maximum and minimum responses displayed the tryptophan requirement at 2.5, 2.3, 2.5 and 2.1 g kg?1 dry diet, respectively. Inclusion of dietary tryptophan in the range of 2.1–2.5 g kg?1 dry diet, equivalent to 6.4–7.6 g kg?1 dietary protein, is recommended in formulating tryptophan‐balanced feed for the culture of this fish species.  相似文献   

15.
A 12‐week growth trial was conducted in a flow‐through system to determine dietary selenium (Se) requirement for on‐growing gibel carp (initial body weight: 76.2 ± 0.05 g, mean ± SEM). Selenomethionine was supplemented to the basal diet to formulate seven semi‐purified diets containing 0.26, 0.58, 0.72, 1.14, 1.34, 1.73 and 2.09 mg Se kg?1 diet. The results showed that plasma superoxide dismutase (SOD) activity significantly increased when fish were fed with 0.58 mg Se kg?1 diet (P < 0.05) and then decreased at 2.09 mg Se kg?1 diet (P < 0.05). Plasma T‐AOC activity was higher in fish fed with 0.72 mg Se kg?1 diet (P < 0.05) and plasma malondialdehyde (MDA) was higher in fish fed with 0.26 mg Se kg?1 diet (P < 0.05). When fish were fed 1.14 mg Se kg?1 diet, hepatic GSH‐Px, T‐AOC, GSH and CAT activities were significantly higher than those fed with 0.26 mg Se kg?1 diet (P < 0.05). Hepatic superoxide dismutase (SOD) activity was higher at 1.34 mg Se kg?1 diet (P < 0.05). Fish liver Se concentrations were significantly higher when fed with 0.72 mg Se kg?1 diet (P < 0.05) and then kept constant when Se ≥ 0.72 mg kg?1 (P > 0.05). Whole‐body and muscle Se concentrations were higher when fed with 1.34 mg Se kg?1 diet (P < 0.05) and kept a plateau when Se ≥ 1.34 mg kg?1 (P > 0.05). In conclusion, based on broken‐line regression of hepatic Se concentrations, hepatic SOD activity and hepatic T‐AOC activity, dietary Se requirements for on‐growing gibel carp was 0.73 mg kg?1, 1.12 mg kg?1 and 1.19 mg kg?1 diet respectively.  相似文献   

16.
Growth response of fingerling Heteropneustes fossilis (6.8 ± 0.2 g; 11.2 ± 0.3 cm) to dietary l ‐leucine levels was assessed by conducting 8‐week feeding trial in a flow‐through system (1–1.5 L min?1) at 28 °C water temperature. Casein–gelatin‐based isonitrogenous (380 g kg?1; crude protein) and isoenergetic [17.9 MJ kg?1; gross energy (GE)] basal diet was supplemented with different levels of l ‐leucine to achieve desired leucine levels ranging between 10 and 22.5 g kg?1 dry diet. Analysed values were 9.9 (Lc9.9), 12.4 (Lc12.4), 15.1 (Lc15.1), 17.4 (Lc17.4), 20.1 (Lc20.1) and 22.4 (Lc22.4) g leucine kg?1 diet. Fishes were stocked randomly in quadruplicates and fed to satiation at 07:00 and 17:30 h. Maximum absolute weight gain (AWG g fish?1), feed conversion ratio (FCR), protein utilization efficiency (PUE%), leucine retention efficiency (LRE%) and haematological parameters were found in fish fed diet Lc17.4. For precise determination of dietary leucine requirement of Singhi, AWG g fish?1, FCR, PUE% and LRE% were subjected to broken‐line and second‐degree polynomial regression analysis. Second‐degree polynomial regression analysis fitted the data more accurately (P > 0.05) exhibiting high R2 values. Hence, based on this analysis, dietary leucine requirement of fingerling H. fossilis is recommended to be 16.5 g kg?1 of the diet, corresponding to 43.4 g kg?1 protein for developing leucine‐balanced commercial feeds.  相似文献   

17.
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.  相似文献   

18.
A 12-week feeding trial was conducted to evaluate the effects of varying levels of dietary arginine on growth, feed conversion, protein productive value and carcass composition of fingerling Heteropneustes fossilis (10.11?±?0.14?cm; 5.87?±?0.07?g). Casein and gelatin-based isonitrogenous (38% crude protein) and isocaloric (14.72 kJ?g?1 digestible energy) amino acid test diets with varying levels of l-arginine (1.00, 1.25, 1.50, 1.75, 2.00 and 2.25?g 100?g?1 of dry diet) were fed to randomly assigned triplicate groups of fish to apparent satiation twice daily at two feeding schedules (08.00 and 17.30?h). Thermal growth coefficient (TGC; 0.86), feed conversion ratio (FCR; 1.97) and protein productive value (PPV; 0.25) were best attained by the group fed diet containing 1.75?g arginine 100?g?1 of dry diet (D4). Carcass protein content also peaked at the above level of dietary arginine whereas carcass lipid showed consistent drop with the increase in dietary arginine level up to 1.75?g 100?g?1 of dry diet. Second-degree polynomial regression analysis at 95% maximum and minimum response of thermal growth coefficient, feed conversion, protein productive value, carcass protein and lipid productive value against varying levels of dietary arginine yielded that dietary arginine in the range of 1.51–1.66?g 100?g?1 of dry diet, corresponding to 3.97–4.37?g 100?g?1 protein is adequate to optimize growth, feed conversion, protein productive value and improve carcass quality in fingerling H. fossilis.  相似文献   

19.
An 8‐week feeding trial was conducted to determine the effect of dietary l ‐methionine supplementation on growth performance, serum immune and antioxidative responses of juvenile Nile tilapia Oreochromis niloticus. Six iso‐nitrogenous (282 g kg?1 crude protein) diets were formulated to contain graded levels of methionine (0.32%, 0.54%, 0.75%, 0.93%, 1.14% and 1.33% of dry weight) at a constant dietary cysteine level of 0.83 g kg?1. Each diet was randomly assigned to triplicate groups of 25 juvenile fish (2.3 ± 0.0 g), which were fed three times daily (8:30, 12:30 and 17:00 hours). The results showed that growth performance and feed utilization significantly improved when dietary methionine levels increased (P < 0.05). Using quadratic regression analysis of weight gain against dietary methionine levels indicated that, the optimal dietary methionine requirement for maximum growth of juvenile tilapia was 9.12 g kg?1 of the dry diet in the presence of 0.83 g kg?1 cystine. In addition, maximum C4 content and lysozyme activity were observed in fish fed 7.50 g kg?1 methionine diet; maximum C3 content and superoxide dismutase activity were obtained in fish fed 9.30 g kg?1 dietary methionine level. While there was no significant difference in serum glutathione peroxidase activity among all methionine supplemented treatments (P > 0.05). Methionine supplementation decreased malondialdehyde content in serum significantly (P < 0.05) when compared with the control diet, while there was no significant difference among supplemented treatments. These data suggested that l ‐methionine affected antioxidant status and promoted serum immune response in juvenile Nile tilapia, and at non‐stressed status, the requirement of dietary methionine in maintaining normal immunity and physiology is lower than that for maximum growth.  相似文献   

20.
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.  相似文献   

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