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1.
An 8‐week feeding trial was conducted to investigate the optimum dietary protein and lipid levels for growth, feed utilization and body composition of Pseudobagrus ussuriensis fingerlings (initial weight: 3.40 ± 0.01 g). Twelve diets containing four protein levels (350, 400, 450 and 500 g kg?1 crude protein) and three lipid levels (50, 100 and 150 g kg?1 crude lipid) were formulated. Fish were randomly allotted to 36 aquaria (1.0 × 0.5 × 0.8 m) with 25 fish to each glass aquarium. Fish were fed twice daily (08:00 and 16:00) to apparent satiation. The results showed that weight gain and specific growth rate (SGR) decreased with increasing dietary lipid level from 50 to 150 g kg?1 at the same dietary protein level. Fish fed the diets containing 150 g kg?1 lipid exhibited higher feed conversion ratio (P < 0.05), lower protein efficiency ratio (PER) and nitrogen retention efficiency (NRE) relative to fish fed the diet containing 50 and 100 g kg?1 lipid. Weight gain and SGR significantly increased with increasing dietary protein from 350 to 450 g kg?1 at the same dietary lipid level, and even a little decline in growth with the further increase in dietary protein to 500 g kg?1. Daily feed intake, NRE and PER were significantly affected by both dietary protein and lipid levels (P < 0.05) and tended to decrease with increasing dietary protein and lipid levels. Whole‐body protein content increased as protein levels increased and lipid levels decreased. Whole‐body lipid and muscle lipid content increased with increasing dietary lipid level, and decreased with increasing dietary protein at each lipid level. There was no significant difference in condition factor and viscerosomatic index among fish fed the diets. Hepatosomatic index was affected by dietary lipid level (P < 0.05), and increased with increasing dietary lipid level at the same protein level. These results suggest that the diet containing 450 g kg?1 protein and 50 g kg?1 lipid with a P/E ratio of 29.1 mg protein kJ?1 is optimal for growth and feed utilization of P. ussuriensis fingerlings under the experimental conditions used in the study.  相似文献   

2.
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   

3.
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   

4.
A growth trial lasting for 12 weeks was conducted in 21 net cages to determine the dietary potassium (K) requirement of subadult grass carp (Ctenopharyngodon idellus) (Average weight: 331.3 g). Seven isonitrogenous and isoenergetic semi‐purified diets were compounded with different dietary K level. The specific growth rate (SGR) of fish was significantly (P < 0.05) improved by dietary K supplementation, SGR and the gill Na+‐K+ ATPase activity increased first and then decreased (P < 0.05) as dietary K level increased. The highest SGR and gill Na+‐K+ ATPase activity values were both observed at 6.38 g kg?1 group. Dietary K level showed significant (P < 0.05) effect on serum superoxide dismutase (SOD) and glucose (GLU), the maximum values of SOD and GLU were in 8.42 and 6.38 g kg?1 group, respectively. The body lipid content of the 6.38 g kg?1 group was significantly (P < 0.05) lower than that of the control. However, the ash content in the 8.42 g kg?1 group was significantly higher than those in the 1.21, 2.21, 4.41 and 6.38 g kg?1 group. When dietary protein was 320 g kg?1 and the waterborne potassium ranged from 6.86 to 9.10 mg L?1, the dietary K requirement for subadult grass carp judged from SGR and gill Na+‐K+ ATPase activity is 5.38 and 7.41 g kg?1 diet, respectively.  相似文献   

5.
This study aimed to investigate the effects of dietary choline supplementation on growth, lipid deposition and intestinal enzyme activities of Megalobrama amblycephala. Fish were fed four diets with two lipid levels (50 and 150 g kg?1) and two choline supplementations (600 and 1600 mg kg?1) for 8 weeks. Feed conversion ratio (FCR), viscerosomatic index (VSI), hepatosomatic index (HSI), intraperitoneal fat (IPF) ratio, whole‐body and muscle lipid contents, intestinal lipase activities and lipoprotein lipase (LPL) activities all increased significantly (P < 0.05) as lipid levels increased, whereas the opposite was true for whole‐body and muscle moisture contents and intestinal amylase activities. VSI, IPF ratio and whole‐body lipid contents all decreased significantly (P < 0.05) with increasing dietary choline supplementations. Weight gain, muscle moisture content all increased significantly (P < 0.05) with increasing dietary choline supplementations when dietary lipid levels reached 150 g kg?1, whereas the opposite was true for FCR, IPF ratio, IPF and liver LPL activities. In addition, abnormal hepatocytes were found in the liver of fish fed 150 g kg?1 lipid with 600 mg kg?1 choline supplementation. The result of this study indicated that extra choline supplementation can improve growth performance, intestinal enzymes activities and reduce excessive lipid deposition of M. amblycephala fed high lipid.  相似文献   

6.
Seven isonitrogenous and isoenergetic experimental diets were formulated to investigate the effect of low molecular weight fish protein hydrolysate (FPH) in diets on growth performance, feed utilization and liver IGF‐I mRNA levels in Japanese flounder (38.80 ± 1.11 g) fed with high plant protein diets. Fish meal protein was, respectively, replaced by 6% (FPH6), 11% (FPH11), 16% (FPH16), 21% (FPH21), 26% (FPH26) FPH of total dietary protein. FPH diets contained a constant high level of plant protein (690 g kg?1) from soybean meal. As a positive control diet, FM2 contained about 590 g kg?1 plant protein and 410 g kg?1 fish meal protein, while negative control diet FM1 contained about 690 g kg?1 plant protein and 310 g kg?1 fish meal protein. The expression levels of liver IGF‐I mRNA were evaluated using real‐time PCR normalized against the 18S rRNA gene. The results showed that moderate low molecular weight FPH (FPH11) improved growth performance and protein retention. Fish fed with FPH11 and control diet FM2 had similar growth and feed utilization, while high‐level low molecular weight FPH did not improve growth performance and protein retention, and depressed liver IGF‐I mRNA expression in Japanese flounder.  相似文献   

7.
A 4‐week growth trial was conducted to investigate the effect of low‐protein diets on the growth and amino acid (AA) composition of yellow catfish, and subsequent recovery when the fish were then switched back to the control diet for a further 4 weeks. Three isolipidic and isocaloric diets containing 390 g kg?1 (Control), 320 g kg?1 (D320) and 260 g kg?1 (D260) graded protein levels were evaluated. During the protein restriction period, specific growth rate (SGR) of D320‐and D260‐treated fish was significantly reduced by 20.79% and 29.21% compared to the control fish, respectively (P < 0.05), while significant improvements in protein retention efficiencies were observed in fish fed with the D320 (12.82%) and D260 (19.58%) diets (P < 0.05). The D260‐treated fish had significantly lower (0.87%) whole‐body essential amino acid (EAA) and significantly higher (0.74%) non‐essential amino aci (NEAA) concentrations compared to the control fish. After a 4‐week realimentation, significant increases in the SGR of the protein‐restricted fish were observed. However, no significant differences in the whole‐body EAA or NEAA concentrations among groups were observed (P > 0.05). The results indicate that previously protein‐restricted yellow catfish can compensate completely in terms of final body weight, growth rate and whole‐body AA concentrations.  相似文献   

8.
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   

9.
Six hundred Labeo rohita (average weight, 6.78 g) were distributed in 24 tanks (25 fish per tank), which were allotted to eight experimental groups in triplicates. Half of the experimental groups were maintained at ambient water temperature of 26 °C, whereas the other half were exposed to 32 °C for 1 week then later maintained at 26 °C for 4 weeks. Fish reared under different temperature regimes were fed one of the four diets containing 200 g kg?1, 300 g kg?1, 400 g kg?1 or 450 g kg?1 protein. Growth, feed efficiency and protein retention were higher at 32 °C and continued for the next 2 weeks after decreasing the temperature. The dietary protein level and water temperature interactions were more effective in modulating the response of hepatic glucokinase than that of hexokinase and pyruvate kinase. In contrast, hepatic gluconeogenesis was not affected by rearing temperature. Hepatic aspartate aminotransferase and alanine aminotransferase activity was found higher (P < 0.05) at low temperature and at high protein level. It is suggested that the metabolic activities of fish are triggered by short‐term exposure to higher temperature and the increased metabolic activity extended for a duration of 3 weeks during which 400 g kg?1 dietary protein level was found to support growth of fish.  相似文献   

10.
A 16‐week feeding trial was conducted to assess the effects of replacing fish meal (FM) with cottonseed meal (CM) on the growth performance, feed utilization, plasma biochemical composition and target of rapamycin (TOR) pathway gene expression of juvenile blunt snout bream (Megalobrama amblycephala). Five isonitrogenous (36% crude protein) and isoenergetic (16 MJ kg?1) diets with graded replacing levels of CM (replacing 0, 25, 50, 75 and 100% FM with CM) and similar lysine and methionine concentrations were fed to triplicate groups of fish. Results revealed that specific growth rate (SGR), feed intake and protein efficiency ratio (PER) of group fed with diets replacing FM with CM up to 50% were significantly higher than others (P < 0.05). However, final body weight and feed conversion ratio (FCR) remained similar up to 25% and thereafter significantly decreased and increased, respectively, as the replacement level increased (P < 0.05). Replacement levels significantly decreased hepatosomatic index and viscerosomatic index (P < 0.05), but did not significantly affect condition factor and whole body compositions. Free gossypol mainly accumulated in liver and significantly increased in diets CM75 and CM100 than CM0 (P < 0.05). Replacement significantly influenced plasma urea contents (P < 0.05). Meanwhile, increasing replacement of FM with CM in diets increased insulin‐like growth factor I (IGF‐1) gene expression in liver of blunt snout bream. Target of rapamycin (TOR) gene expression in diet CM100 was significantly lower than that in diets CM0 and CM75, while the eukaryotic translation initiation factor 4E‐binding protein 2 (4E‐BP2) gene expression was not affected by the replacement level of CM in diets. Therefore, based on final body weight and FCR, it suggested that up to 25% of FM (150 g kg?1 in basal diet) could be replaced by CM in diets, which was 112.5 g kg?1 FM and 192.9 g kg?1 CM, for juvenile blunt snout bream.  相似文献   

11.
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   

12.
A feeding trial was conducted to evaluate the optimum requirement of dietary available phosphorus (AP) for juvenile walking catfish, Clarias leather. Six practical diets were formulated to contain graded levels (2.2, 3.9, 5.5, 7.1, 8.8 and 10.4 g kg?1) of AP from dietary ingredients and monocalcium phosphate. Each diet was randomly fed to triplicate groups of fish with initial mean weight of 7.94 ± 0.08 g in floating cages (1.5 × 1.5 × 2.0 m) suspended in an earthen pond, and each cage was stocked initially with 60 fish. Fish were fed thrice daily (07:30, 13:00 and 17:30) to apparent satiation for 10 weeks. Both specific growth rate (SGR) and protein efficiency ratio significantly increased with increasing AP from 2.2 to 5.5 g kg?1 (P < 0.05) and then levelled off. Dietary AP levels significantly influenced whole‐body protein, lipid and ash contents as well as condition factor and hepatosomatic index (P < 0.05). Whole‐body and vertebrae phosphorus contents showed similar patterns as SGR in response to dietary AP content. Broken‐line analyses based on SGR, phosphorus contents in the vertebrae and whole‐body indicated the AP requirements were 5.8, 7.2 and 7.5 g kg?1, respectively.  相似文献   

13.
An 8‐week feeding trial was conducted to evaluate the effects of dietary aflatoxin B1 (AFB1) on growth performance, haematological parameters and histological changes in juvenile Pacific white shrimp, Litopenaeus vannamei. Six practical diets (455 g kg‐1 protein, 78 g kg‐1 lipid) with different levels of AFB1 (0, 25, 50, 100, 500, 1000 μg kg?1) were formulated. Each diet was fed to triplicate groups of shrimps (initial weight: 0.52 g). The results showed that shrimp fed with control diet (0 μg kg?1 AFB1) had significant higher weight gain (WG) and specific growth rate (SGR) than other groups. However, there were no significant differences in feed efficiency (FE) or hepatosomatic index (HSI) among all groups. Compared to the control diet, AFB1 supplementation significantly changed the activities of shrimp serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total antioxidant capacity (T‐AOC) and glutathione S‐transferase (GST) and the content of cholesterol (CHO). Histological damages were identified in the hepatopancreas of shrimp when dietary AFB1 level was over 107.6 μg kg?1. Based on this study, it was concluded that the AFB1 level in Pacific white shrimp diet should be <38.1 μg kg?1.  相似文献   

14.
An 8‐week feeding trial was conducted to determine the optimal dietary arginine requirement for juvenile swimming crab Portunus trituberculatus. Six isonitrogenous and isolipidic experimental diets were formulated to contain graded arginine levels which ranged from 15.9 to 33.0 g kg?1. Each diet was randomly assigned to triplicate groups of 60 juvenile swimming crabs (4.72 ± 0.12 g). The results indicated that dietary arginine had significant effects on weight gain (WG), specific growth rate (SGR), protein productive value, feed efficiency and protein efficiency ratio. Weight gain and SGR significantly increased with the dietary arginine increasing from 15.9 to 27.4 g kg?1, while with the further increasing from 27.4 to 33.0 g kg?1, WG and SGR did not increase significantly. Maximum arginine, proline and total essential amino acid contents in muscle were observed in 27.4 g kg?1 group diet. The swimming crab fed the diet with lower dietary arginine level showed higher AST and lower ALT in the serum. Crab fed with the lower dietary arginine level had significantly lower ALT in the serum than the other groups. Haemolymph indexes were significantly affected by the dietary arginine level except for the cholesterol concentration, and the highest values were all found in 27.4 g kg?1 group diet. The two slope broken‐line model using SGR showed that the optimal dietary arginine requirement was 27.7 g kg?1 of the dry matter (56.0 g kg?1 dietary protein) for juvenile swimming crab.  相似文献   

15.
Present experiment was conducted to determine the effect of different feeds with varying protein levels on the growth, survival and reproductive performance of zebrafish, Danio rerio. The control diet (T1) was wild‐collected zooplankton from local fish ponds, while test diets with 350 g kg?1 protein (T2), 400 g kg?1 protein (T3) and 450 g kg?1 protein (T4) were formulated and fed to fish for a period of 210 days. The significantly (P < 0.05) highest mean weight gain and specific growth rate were observed in T1, which were similar with T3 and T4. The significantly (P < 0.05) highest number of egg production per female and relative fecundity were found in T1, followed by T4 and T3 while T2 produced lowest number of eggs. No significant (P > 0.05) differences were observed in brood survival rate, fertilization and hatching rate among the dietary treatments. The highest (P < 0.05) fry survival rate was recorded in T1, followed by T3 and T4. Thus, it is suggested that control diet i.e. mixed zooplankton exhibited better growth, reproductive performance and fry survival rate. However, diet containing 400 g kg?1 crude protein also gave comparable results in terms of growth, survival and reproductive performance of zebrafish.  相似文献   

16.
A 10‐week feeding trial with four dietary protein levels (400, 450, 500 and 550 g kg?1 crude protein) and two dietary lipid levels (80 and 160 g kg?1 crude lipid) was conducted to assess optimum dietary protein and lipid levels for the growth, feed utilization and body composition of juvenile Manchurian trout (initial weight 11.80 ± 0.15 g). Fish were fed twice daily (08:30 and 16:30 h) to apparent satiation. The results showed that fish fed the diet with 500 g kg?1 protein and 80 g kg?1 lipid had the highest growth and feed efficiency. However, fish fed the diet with 450 g kg?1 protein and 160 g kg?1 lipid showed comparable growth to that of the fish fed diet 5 (500/80) and had higher protein efficiency ratio (PER), nitrogen retention (NR) and energy retention (ER) than other groups (P < 0.05). Growth, PER, NR and ER of fish fed the 160 g kg?1 lipid diet was significantly higher (P < 0.05) than that of fish fed the 80 g kg?1 lipid diet at 400 and 450 g kg?1 protein diet, whereas these values showed an opposite trend at 500 and 550 g kg?1 protein diet, and the lowest PER, NR and ER was found by fish fed the 400 g kg?1 protein diet with 80 g kg?1 lipid. Fish fed diets with 400 g kg?1 protein had lower feed intake (FI) than that of other groups. Feed intake of fish fed 80 g kg?1 lipid level was significantly lower than that of fish fed 160 g kg?1 lipid diet at 400 g kg?1 protein (P < 0.05), while no significant differences were observed at 450, 500 and 550 g kg?1 protein‐based diets. Contrary to moisture content, lipid content of whole body and muscle increased significantly (P < 0.05) with increasing lipid levels. The results of this study indicated that the diet containing 450 g kg?1 protein and 160 g kg?1 lipid, with a P/E ratio of 23.68 g protein MJ?1 would be suitable for better growth and feed utilization of juvenile Manchurian trout under the experimental conditions and design level used in this study.  相似文献   

17.
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.  相似文献   

18.
A growth trial was conducted to evaluate the effects and safety of nucleotides in low fish meal diets on the growth performance, antioxidative capacity and intestinal morphology of turbot (Scophthalmus maximus). High fish meal control diet was formulated with 500 g kg?1 fish meal. Seven levels (0.075, 0.15, 0.225, 0.300, 1.5 and 3.0 g kg?1, respectively) of nucleotides were added to a low fish meal basal diet, which was formulated with 400 g kg?1 fish meal. The eight experimental diets were fed to groups of juvenile turbot (initial weight: 6.0 ± 0.03 g) for 60 days. Results showed that compared with high fish meal control diet, low fish meal basal diet treatment had lower total antioxidative capacity (T‐AOC), glutathione peroxidase activity, fold height of proximal and distal intestine, enterocyte height of all evaluated enteric section and microvillus height of mid‐intestine and distal intestine (P < 0.05). However, supplemented nucleotides in diets could significantly improve growth (specific growth rate, SGR), feed utilization, antioxidative capacity and intestinal morphology of turbot (P < 0.05). Broken‐line regression analysis of SGR and T‐AOC showed that the optimal supplemental levels of dietary nucleotide for juvenile turbot were 0.366 and 0.188 g kg?1, respectively. In summary, 0.300 g kg?1 of dietary nucleotides was helpful in improving growth, feed utilization, antioxidative capacity and intestinal morphology of turbot fed with low fish meal diet. Excessive dietary nucleotides (3.0 g kg?1) might cause oxidative stress and morphological damage in intestine and then reduce the growth of turbot.  相似文献   

19.
The effects of dietary phosphorus (P) on growth, body composition and immunity of young taimen (Hucho taimen) were studied. Six purified diets contained graded levels (2.3‐control, 4.0, 5.6, 7.5, 9.1 and 10.8 g kg?1 diet) of available P. Each diet was fed to triplicate groups of 30 fish with an initial average weight (55.31 ± 0.38) g for 84 days. The weight gain, specific growth rate and feed conversion ratio were improved by dietary available P up to 4.35 g kg?1 (P < 0.05) and then levelled off. Hepatosomatic index and body crude lipid content decreased significantly with increasing P levels, while ash contents and P concentrations in the whole body and vertebrae increased by dietary available P up to 4.36 and 4.44 g kg?1 and then levelled off respectively (P < 0.05). Liver superoxide dismutase and glutathione peroxidase and plasma alkaline phosphatase activities in the treatment groups were significantly higher compared with the control group (P < 0.05). Plasma IgM contents increased linearly with increasing dietary P from 4.0 to 9.1 g kg?1 group and then decreased. Dietary P supplementation reduced plasma triglyceride, malondialdehyde and liver malondialdehyde contents. There were no significant effects on plasma total protein, albumin, globulin, glucose, aspartate aminotransferase and alanine aminotransferase, catalase, lysozyme and liver catalase compared with the control group (P > 0.05). Broken line regression analysis indicated that dietary available P requirement was 4.34 and 4.35 g kg?1, based on weight gain and P concentration in the whole body respectively.  相似文献   

20.
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   

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