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1.
The dietary total and available requirement of tryptophan of Nile tilapia fingerlings was determined using linear regression analysis. Six hundred fish (3.4 ± 0.0 g) were fed diets containing 296.4 g/kg of crude protein and 14.1 MJ/kg of digestible energy. Five extruded diets containing 2.5, 3.0, 3.4, 3.8 and 4.2 g/kg of total tryptophan were evaluated. Fish were fed four times a day during 45 days. Final body weight, weight gain, feed intake, feed conversion ratio and net protein utilization of fish fed Trp 3.4 and Trp 3.8 diets were improved compared to fish fed Trp 2.5 and Trp 4.2 diets. No significant differences in survival rate, whole‐body moisture and ash were observed. Whole‐body amino acid profile of fish fed different diets did not differ statistically (p > .05). Fish fed Trp 3.0 and Trp 3.4 diets showed higher tryptophan retention compared to fish fed Trp 2.5 and Trp 4.2 diets. Excepting blood glucose, no effects of dietary tryptophan on haematological parameters were observed. The dietary total tryptophan requirement of Nile tilapia fingerlings based on weight gain was estimated to be 3.4 g/kg (11.0 g/kg of dietary crude protein) or 3.0 g/kg of available tryptophan (11.0 g/kg of dietary digestible protein).  相似文献   

2.
Six isoproteic diets were designated to evaluate the effects of dietary lipid levels (from 70 to 270 g/kg) on the growth performance, feed utilization, digestive tract enzyme activity and lipid deposition of juvenile Brachymystax lenok (average initial weight 0.54 ± 0.04 g). Each diet was fed to triplicate tanks (30 fish per tank) in an indoor closed recirculating system for 9 weeks. Final body weight and weight gain were highest in fish fed 190 g/kg diet and lowest in fish fed the 70 g/kg diet. Specific growth rate of fish fed with 190 g/kg diet was significantly higher than those fed with 70 and 270 g/kg diets (p < .05). Protein efficiency ratio of fish fed with 70 g/kg diet was significantly lower than the 110–230 g/kg treatments and was not significantly different from the 270 g/kg treatment. Fish fed with 270 g/kg diet had significantly higher hepatosomatic index and viscerosomatic index than those fed with 70–190 g/kg diets (p < .05). Intraperitoneal fat ratio and the whole‐body lipid content had a trend to increase with increase in dietary lipid level. Muscle crude lipid content increased up to 190 g/kg with increase in dietary lipid level. Lipid retention decreased with increase in dietary lipid level, while no significant differences in protein intake and retention levels were observed in fish among all treatments. Lipase activity of the mixture of pyloric caeca and foregut in fish fed 190 and 230 g/kg diets was significantly higher than those fed 70 and 110 g/kg diets. Midgut and hindgut lipase activities of fish were significantly higher than those fed the 190 and 230 g/kg diets. In conclusion, based on the second‐order polynomial model of WG and FCR, this study suggested that 173.8–195.0 g/kg dietary lipid levels were appropriated for B. lenok.  相似文献   

3.
To investigate the response of gibel carp to dietary lysine levels in zero fish meal (FM) diets, 8 experimental diets were designed. Among them, diet 1 and diet 2 with 150 g/kg FM, methionine, lysine and threonine were supplemented in diet 2. Diet 3 was without FM but matched the amino acid profile of diet 2 except for lysine. Diets 4–8 were based on diet 3, with graded levels of lysine. After 8‐week feeding trail, final body weight, weight gain (WG), specific growth rate, feed conversion ratio (FCR) and feed intake were significantly improved by diets 1–2 and 6–8 compared with diet 3. Plasma glucose, triglyceride, immunoglobulin G and aspartate aminotransferase levels in diets 4–8 were higher than those in diet 1. Apparent digestibility coefficients (ADCs) of protein, energy, methionine, lysine, valine, histidine and phenylalanine in diet 1 were significantly lower than those in diet 6. The highest ADC of isoleucine was found in diet 3. TOR, IGF‐1, JAK3, STAT4, STAT6 and PepT2 mRNA levels were significantly increased with increasing dietary lysine up to a certain level in zero FM diet and lower than diets 1–2. Based on WG and FCR, the optimal lysine requirement of juvenile gibel carp was determined to be 24.4 g/kg and 24.2 g/kg (65.9 g/kg and 65.4 g/kg of dietary protein) in zero FM diet, respectively, using quadratic regression analysis.  相似文献   

4.
This experiment was designed to investigate the effects of dietary valine on the growth performance, feed utilization, digestive enzymes, serum antioxidant and immune indices of juvenile Trachinotus ovatus and determine its valine requirement. Six diets with different concentrations of L‐valine (15.0, 16.6, 18.6, 20.7, 23.5 and 25.4 g/kg dry diet, defined as diet Val‐1 to Val‐6.), were formulated to contain 430 g/kg crude protein with fish meal, soybean meal, peanut meal and precoated crystalline amino acids. Each diet was randomly assigned to triplicate treatments of 20 fish (the initial body weight was 5.34 ± 0.03 g) for 8 weeks. The results indicated that the final body weight and percent weight gain (PWG) increased with increasing valine concentration up to 18.6 g/kg (diet Val‐3), whereas the diets containing higher valine concentration reduced the growth performance significantly (p < .05). Moreover, the protein efficiency ratio, body protein deposition (BPD), muscle protein content, intestinal amylase and pepsin activities, serum T‐AOC, LZM activities, IgM, complement 3 and complement 4 concentration had a similar trend with PWG, and the trend of feed conversion ratio, serum AST, ALT activities, urea and MDA content was opposite. Meanwhile, the lipid contents of whole fish and muscle in diet Val‐6 were particularly lower than other diets (p < .05). The survival rate of diet Val‐1 was lowest in this study and was significantly lower than diet Val‐2 (p < .05). The results of polynomial regression based on PWG and BPD indicated that the optimal dietary valine requirement for Trachinotus ovatus reared in seawater‐floating net cages was 19.87–20.17 g/kg valine of dry diet, correspondingly 46.22–46.91 g/kg of dietary protein.  相似文献   

5.
A 12‐week feeding trial was conducted using Nile tilapia, Oreochromis niloticus (L.) to evaluate the interactive effects of fishmeal replacement and salinity on growth, feed utilization efficiencies and relative expression of growth related genes. Two iso‐nitrogenous and iso‐energetic diets were prepared (32% protein). The control diet included 15% fishmeal (FM diet) and fishmeal component in non‐fishmeal diet (NFM) was eliminated by a mixture of poultry by‐product meal, high protein distillers dried grains and distillers dried grains with soluble. The NFM diet was supplemented with DL‐methionine and L‐lysine. Duplicated group of fish with initial mean weight of 6 g, reared in four salinity levels (0, 4, 8 and 12 g/L) were fed one of the two diets twice a day to near satiety. At the end of the experiment, growth, feed utilization efficiency and expression of growth related genes were compared. The specific growth rate (SGR), mean feed intake (MFI) and feed conversion ratio (FCR) were not affected by the diets while salinity effects were significant. The fish in the 4 g/L salinity showed the highest SGR and MFI while fish in the 0 g/L treatment showed the lowest FCR. Relative expression of hepatic IGF‐I and IGF‐II was regulated by salinity but not by the diet. Expression of growth hormone receptor gene was not affected by either diet or salinity. The present findings provide evidence for the possibility of total fishmeal replacement in saline waters (0–12 g/L) without compromising growth, feed utilization and body composition of Nile tilapia.  相似文献   

6.
A 50‐day feeding trial was conducted to examine the effects of dietary protein and lipid levels on growth, feed utilization, body composition and swimming performance of giant croaker, Nibea japonica. Fish (initial body weight 44.6 g ind−1) were fed ten test diets which were formulated at 5 crude protein levels (360, 400, 440, 480 and 520 g kg−1) and 2 crude lipid levels (90 and 150 g kg−1). In addition, a raw fish diet (fillet of small yellow croaker) served as the reference. The weight gain (WG) increased, whereas the feed intake (FI) and feed conversion ratio (FCR) decreased, with increasing dietary protein level from 360 to 520 g kg−1. At the same dietary protein level, no significant difference was found in the WG between fish fed the diets containing 90 or 150 g kg−1 crude lipid. Fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid exhibited higher WG, nitrogen retention efficiency (NRE) and energy retention efficiency (ERE) but lower nitrogen wastes output (TNW). At the end of the feeding trial, the hepatosomatic index (HSI) and viscerosomatic index (VSI) decreased, whereas the body protein content increased, with increase in dietary protein level. The body lipid content was higher in fish fed at the 150 g kg−1 lipid level than in fish fed at the 90 g kg−1 lipid level. No significant difference was found in the maximum sustained swimming speed (MSS) between fish fed at different dietary protein and lipid levels. The WG, NRE, ERE and condition factor (CF) were higher, whereas the FI, FCR, HSI, VSI and TNW were lower, in fish fed the raw fish diet than in fish fed the diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. No significant difference was detected in the MSS between fish fed the raw fish diet and diet containing 480 g kg−1 crude protein and 90 g kg−1 crude lipid. The results of this study suggest that the suitable dietary crude protein and crude lipid levels are 480 g kg−1 and 90 g kg−1 for giant croaker reared in net pens.  相似文献   

7.
A 16‐week feeding trial was conducted to determine the dietary pantothenic acid requirement of fingerling Channa punctatus. Six casein–gelatin‐based diets (450 g/kg CP; 18.39 kJ/g GE) with graded levels of pantothenic acid (0, 10, 20, 30, 40 and 50 mg/kg diet) were fed to triplicate groups of fish (6.2 ± 0.71 cm; 4.26 ± 0.37 g) near to apparent satiation. The growth evaluation in terms of absolute weight gain (AWG), feed conversion ratio (FCR) and protein retention efficiency (PRE) indicated the best performance (p < .05) in fish fed diet containing 30 mg/kg pantothenic acid. Highest haemoglobin, haematocrit and RBCs counts were also obtained in fish fed diet with 30 mg/kg pantothenic acid. Mean cell haemoglobin and mean cell volume were found to be lowest in fish fed pantothenic acid‐free diet indicating the anaemia in this group of fish. Superoxidase dismutase and catalase activities of liver tissue were found to improve (p < .05) with the increasing levels of dietary pantothenic acid from 0 to 30 mg/kg. However, liver pantothenic acid concentration responded positively with the increasing levels of pantothenic acid up to 40 mg/kg diet and then stagnation in liver pantothenic acid concentration with the further inclusion of pantothenic acid was recorded. Second‐degree polynomial regression analysis of AWG, FCR and PRE exhibited the pantothenic acid requirement at 36.4, 32.8 and 34.7 mg/kg diet, respectively. Data generated during this study would be useful in formulating pantothenic acid‐balanced commercial feeds for the intensive culture of this fish.  相似文献   

8.
A 12‐week feeding trial was conducted to determine the dietary phosphorus requirement of Heteropneustes fossilis fingerlings (7.7 ± 0.04 g). Fish were fed casein–gelatine‐based purified diets in triplicate groups near satiation with seven different levels of dietary phosphorus (3.2, 5.2, 7.2, 9.2, 11.2, 13.2 and 15.2 g/kg dry diet). All diets were formulated to be isoproteic (400 g/kg) and isoenergetic (17.89 kJ/g). Highest absolute weight gain (68.38 g/fish), best feed conversion ratio (1.48), protein retention efficiency (30.74%), protein gain (12.44 g/fish), haemoglobin (11.19 g/dL), RBCs (3.12 x106/mm3), haematocrit (33.44%) and serum phosphate (2.82 mg/L) were found at 9.2 g/kg phosphorus. Hepatic superoxide dismutase and catalase activity were also significantly influenced by the dietary phosphorus levels. Whole body and vertebrae phosphorus concentrations increased significantly as the amount of dietary phosphorus increased from 3.2 to 11.2 g/kg dry diet and then plateaued. More accurate information on dietary phosphorus requirement was obtained by subjecting the AWG, FCR, vertebrae phosphorus and whole body phosphorus concentrations data against various levels of dietary phosphorus to broken‐line analysis, which yielded the requirement in the range of 9.0–11.0 g/kg for optimum growth and mineralization of H. fossilis.  相似文献   

9.
Two growth trials were designed to evaluate the utilization of dried fermented biomass (DFB) in commercial type feed formulation for Pacific white shrimp, Litopenaeus vannamei. In trial 1, four experimental diets were formulated to utilize increasing levels (0, 25, 50 and 100 g/kg) of spray‐dried fermented biomass (SDFB) as a replacement of fish meal (FM). Results indicated that SDFB can be utilized up to 50 g/kg as a substitution for FM without causing growth depression in shrimp. However, dietary SDFB supplementation at 100 g/kg significantly reduced the weight gain (WG) of shrimp and increased feed conversion ratio (FCR). This reduction in performance is likely due to palatability or nutrient imbalances of the feed. In trial 2, nine experimental diets were formulated with increasing levels (0, 20, 40, 60 and 120 g/kg) of spray‐dried (S) or granular (G) DFB to replace soy protein concentrate (SPC) or SPC + corn protein concentrate (CPC). This allowed the comparison between spray‐dried and ring‐dried products. Ring drying produced a granular product, reducing dust and increasing product particle size. Shrimp fed with diet containing 20 g/kg GDFB performed the best in terms of final mean weight, WG and FCR. Significantly reduced growth and increased FCR were observed in shrimp fed diets containing 60 and 120 g/kg SDFB. Lipid content of whole body was significantly reduced when GDFB was incorporated at 120 g/kg. No significant differences were detected in survival, protein retention efficiency as well as protein and ash contents of the whole shrimp. Results from analysis of covariance indicated that the processing method (covariant) had a significant effect on final mean weight, WG and FCR. In general, shrimp fed with diet containing granular product performed better as compared to those fed with diets utilizing spray‐dried product. GDFB can be utilized in the diets up to 120 g/kg in practical shrimp feeds as a substitute for SPC and CPC without compromising the growth of shrimp. However, a significant reduction in WG was observed in the diets containing 60 and 120 g/kg SDFB. The results in the current study demonstrate that processing changes to produce a granular product produced an improved feed ingredient for shrimp.  相似文献   

10.
Yeasts used as a probiotic in fish diets could stimulate fish resistance against bacterial infection and could enhance the activities of digestive enzymes in fish guts. In addition to yeast importance, dietary protein is another important part in fish diets that should be carefully optimized to meet fish requirement. It is proposed that the yeast supplementation may enhance the dietary protein turnover and reduce the protein requirement for fish. Therefore, the interactive effects of dietary protein and yeast levels on the growth performance of Nile tilapia, Oreochromis niloticus (L.) fry and their challenge against Aeromonas hydrophila infection was evaluated. In the present study, ten experimental diets were formulated to contain either 35% or 45% crude protein (CP). For each protein level treatment, bakery yeast (Saccharomyces cerevisiae) was supplemented at 0.0, 0.50, 1.0, 2.0, or 5.0 g/kg diet. Fish (0.25–0.48 g) were distributed at a rate of 25 fish per 140-L aquarium. For each diet, triplicate aquaria were fed twice a day, 5 days a week for 12 weeks. Fish growth and feed utilization were significantly affected by either dietary protein or yeast levels alone, while no significant effect of their interaction was observed. The highest fish growth was obtained at 1.0–5.0 g yeast/kg diet at both protein levels; however, the fish performance at 45% CP was better than that fed on 35% CP diets. The optimum feed conversion ratio (FCR) was obtained when fish fed on 1.0–5.0 and 2.0–5.0 g yeast/kg diet at 35 and 45% CP, respectively. The cumulative fish mortality, after interperitoneal injection with A. hydrophila for 10 days, and bactericidal activity was significantly higher in fish fed 35% CP diets than those fed 45% CP diets. Both variables decreased significantly with the increase in yeast levels. The lowest bacterial count and bactericidal activity were obtained in fish fed 5.0 g yeast/kg diet irrespective to dietary protein levels. It could be concluded that the inclusion of live bakery yeast in practical diets could improve the growth performances, feed utilization, and physiological status of Nile tilapia fry and their challenge against A. hydrophila infection. Moreover, fish performance when fed 45% CP diet was better than those fed 35% CP diet. Based on these results, the most suitable yeast level for maximum Nile tilapia growth was determined to be 2.0 g yeast/kg diet with 45% CP diet; however, this level was recommended to stimulate their productive performance and enhances their resistance against A. hydrophila infection.  相似文献   

11.
A six‐week growth trial was performed to estimate the dietary protein requirements for maximum growth of juvenile Brazilian sardine (Sardinella brasiliensis) based on growth performance, feed utilization, body composition and digestive enzyme activity. Six isoenergetic diets were formulated to contain protein levels that increased from 250 to 500 g/kg. Each diet was randomly assigned to triplicate groups of 160 fish with mean initial body weight of 0.93 ± 0.13 g, which were fed four times a day to apparent satiation. Growth tended to increase with the increase in the dietary protein level up to 400 g/kg. Total protein intake was indirectly correlated to apparent protein utilization. No significant differences in whole‐body composition were found between fish fed the different protein levels. Acid protease and neutral lipase activities did not show significant differences among the different protein dietary groups. Alkaline protease activity increased in fish fed up to 350 g/kg of protein and amylase activity in fish fed up to 400 g/kg. Using polynomial regression, 367 g/kg was estimated to be the optimum dietary protein requirement for maximum weight gain of juvenile Brazilian sardines.  相似文献   

12.
An 8‐week feeding trial was conducted to evaluate the effects of dietary choline levels on growth performance, antioxidant capacity and lipid metabolites in juvenile Pacific white shrimp. Six isonitrogenous and isolipidic diets were formulated to supply 0, 1,000, 2,000, 4,000, 6,000, 10,000 mg/kg choline chloride, and dietary choline levels were analysed to be 1,317 (basal diet), 1,721, 2,336, 3,294, 5,421 and 9,495 mg/kg, respectively. Dietary choline levels significantly influenced percent weight gain (PWG) and protein efficiency ratio (PER), with the highest PWG was observed in shrimp fed the 5,421 mg/kg choline diet. However, there were no significant differences in proximate composition of whole body and muscle. Shrimp fed the diet containing 2,336 mg/kg choline had lower HDL and LDL in haemolymph than those fed the basal diet (1,317 mg/kg diet). Dietary choline prevented the accumulation of free radicals and improved antioxidant capacity by increasing catalase activity and reducing malondialdehyde content. Based on broken‐line regression and quadratic regression analysis between PWG against dietary choline levels, the optimal choline requirements were estimated to be 3,254.1 and 6,488.3 mg/kg for juvenile L. vannamei, respectively.  相似文献   

13.
An 8‐week feeding trial was conducted to determine dietary lysine requirement of juvenile Pseudobagrus ussuriensis (initial body weight: 0.60 g). Six isonitrogenous (crude protein, 400 g/kg) and isolipidic (crude lipid, 50 g/kg) diets were formulated to contain graded levels of dietary lysine (12.8, 19.9, 26.5, 34.0, 40.8 and 44.1 g/kg dry diets, respectively). The results indicated that weight gain, specific growth rate, productive protein value and protein efficiency ratio increased, while feed conversion ratio decreased with increasing dietary lysine level up to 34.0 g/kg dry diet and then levelled off. Fish fed diet with 12.8 g/kg lysine had the lowest lysine content (58.6 g/kg dry matter) in muscle, while fish fed diet with 34.0 g/kg lysine had the highest value (61.6 g/kg dry matter; p < .05). Broken‐line analysis on the basis of weight gain showed that the optimal dietary lysine requirement for maximum growth of juvenile Pseudobagras ussuriensis is 33.5 g/kg dry diet (82.4 g/kg dietary protein). Quadratic regression analysis of protein efficiency ratio against dietary lysine levels indicated that the optimal dietary lysine requirement of juvenile Pseudobagras ussuriensis is 36.4 g/kg dry diet (89.5 g/kg dietary protein).  相似文献   

14.
A feeding trial was conducted to evaluate the potential of replacing fishmeal with poultry byproduct meal (PBM) and soybean meal in diets for largemouth bass, Micropterus salmoides. A reference diet (C) contained 400 g/kg fishmeal, and 40 or 60% of the fishmeal was replaced with a blend of pet‐food‐grade PBM and soybean meal (diets PP1 and PP2) or a blend of feed‐grade PBM and soybean meal (diets PF1 and PF2). No significant differences were found in weight gain, nitrogen retention efficiency (NRE), condition factor, and body composition among fish fed diets PP1, PP2, PF1, and PF2. Feed intake and feed conversion ratio (FCR) were higher in fish fed diet PF1 than in fish fed diet PP1. No significant differences were found in weight gain, NRE, condition factor, and body composition between fish fed diet C and diets PP1, PP2, PF1, and PF2. The feed intake and FCR were lower in fish fed diet C than in fish fed diets PP2, PF1, and PF2. This study reveals that dietary fishmeal level for largemouth bass could be reduced to 160 g/kg by inclusion of PBM and soybean meal in combination.  相似文献   

15.
Groups of milkfish juveniles (mean initial weight 7.7 g) were fed semipurified diets containing 0.9, 1.4, 2.1, 3.1, 4.1 and 6.1 g tryptophan/kg dry diet for 12 weeks. The mean crude protein content of the diets (containing white fishmeal, gelatin and free amino acid mixture to simulate the pattern of hydrolysed milkfish protein) was 49%. On the basis of the growth response, the tryptophan requirement of milkfish juveniles was estimated to be 3.1 g/kg diet. Fish fed low levels of tryptophan exhibited low weight gains and poor feed conversion ratios. Survival (92–100%) was consistently high in all treatments. Fish fed diets containing tryptophan levels greater than 3.1 g/kg had slightly lower survival rates. The activity of hepatic tryptophan pyrrolase showed no significant differences with increasing dietary tryptophan levels. No nutritional deficiency signs were observed other than the depression in growth rates in fish given the tryptophan deficient diets.  相似文献   

16.
The study evaluated effects of cholesterol supplementation in a diet with high soybean meal (SBM) on the growth and cholesterol metabolism of giant grouper (Epinephelus lanceolatus). All‐fish‐meal diet was used as control. The diet including SBM (replaced 50% of the fish meal protein, SBM diet) and the SBM diet supplemented with 10 g/kg cholesterol (SBM + cholesterol) were used as experimental diets. Three diets were each fed to triplicate groups of juvenile grouper (initial body weight: 12.39 ± 0.36 g) in a recirculating aquaculture system for 8 weeks. Grouper fed the control diet showed higher (p < .05) weight gain, feed intake, feed efficiency and protein efficiency ratio than the other two dietary treatments. Hepatic cholesterol concentrations and 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase gene expressions were higher in fish fed the control diet than fish fed the control diet and SBM + cholesterol diet. Hepatic cholesterol 7α‐hydroxylase gene expression was higher in fish fed the SBM + cholesterol diet than that in fish fed the control diet. Results indicate that giant grouper on a diet low in cholesterol can regulate cholesterol synthesis, suggesting that the reduced dietary cholesterol intake in the fish fed diet containing SBM is sufficiently compensated by increased cholesterol synthesis.  相似文献   

17.
A study was conducted to evaluate low‐protein traditional or alternative diets for pond‐raised hybrid catfish, Ictalurus punctatus × Ictalurus furcatus. Three 24% protein diets containing decreasing levels of soybean meal (30, 20, and 15%) and increasing levels of cottonseed meal and corn germ meal were compared with a 28% protein control diet. Hybrid catfish fingerlings (mean initial weight = 71 g/fish) were stocked into 20 earthen ponds (0.04 ha) at a density of 14,826 fish/ha with five ponds per dietary treatment. Fish were fed once daily to apparent satiation for a 191‐d growing season. There were no significant differences in total diet fed, net yield, weight gain, feed conversion ratio (FCR), survival, or fillet proximate nutrient composition among dietary treatments (P ≥ 0.10). However, regression analysis showed for fish fed 24% protein diets there was a linear increase in FCR as soybean meal levels decreased (P = 0.06). Compared with fish fed the 28% protein control diet, fish fed 24% protein diets had lower carcass and fillet yield. Results demonstrate a 24% protein alternative diet containing 20% soybean meal may be substituted for 28% protein diets for hybrid catfish during food fish production.  相似文献   

18.
This study was conducted to determine effects of dietary Fe levels on growth performance, hepatic lipid metabolism and antioxidant response for juvenile yellow catfish Pelteobagrus fulvidraco. Yellow catfish were fed six isonitrogenous and isolipidic diets containing Fe levels of 16.20, 34.80, 54.50, 76.44, 100.42 and 118.25 mg/kg for 8 weeks. Weight gain (WG) and specific growth rate (SGR) increased with dietary Fe levels from 16.20 to 54.50 mg/kg diet and then plateaued over the level. Feed conversion rate (FCR) was highest and protein efficiency rate (PER) was lowest for fish fed the lowest Fe levels of diet. Fe contents in whole body and liver increased with increasing dietary Fe levels. Hepatic lipid content was lowest, but mRNA levels of carnitine palmitoyltransferase (CPT‐1) and peroxisome proliferator‐activated receptor α (PPARα) were highest for fish fed 54.50 mg Fe/kg diet. Fish fed adequate dietary Fe levels reduced hepatic malondialdehyde (MDA) level and increased activities of antioxidant enzymes Superoxide dismutase (SOD), Catalase (CAT) and GS. Based on the broken‐line regression analysis of WG against dietary Fe levels, optimal dietary Fe requirement for yellow catfish was 55.73 mg Fe/kg diets. Fe‐induced changes in MDA levels and antioxidant enzymatic activities paralleled with the change in hepatic lipid content, suggesting the potential relationship between oxidative stress and hepatic lipid accumulation in yellow catfish.  相似文献   

19.
This study investigated the effect of two lipid sources on reproduction performance and growth in pearl gourami. For this purpose, 180 fish (3.32 ± 0.25 g) were fed with three isoenergetic (19.80) and isonitrogenous diets (480 g/kg protein) including FO (80 g/kg fish oil), FS (40 g/kg fish oil and 40 g/kg soybean oil) and SO (80 g/kg soybean oil) for 10 weeks before maturation. At the end of the trial, there was no significant difference in weight gain, feed conversation ratio and body composition between fish fed FO and FS diets. Individuals fed dietary FO had significantly higher levels of n‐3 long‐chain polyunsaturated fatty acids in the muscle (130.5 g/kg lipid) and ovary (140.4 g/kg lipid) as compared with those fed SO diet (64.5, 103.6 g/kg, respectively) (p < .05). Feeding pearl gourami with FO and FS diets enhanced regarding absolute fecundity, relative fecundity, the fertilization rate, larvae total length and survival at 3 day posthatch (p < .05). Also, 17 beta‐estradiol in plasma of fish fed dietary FO (6.2 ng/L) was higher than those fed SO diet (1.7 ng/L) (p < .05). In conclusion, we suggest FS diet for broodstock nutrition of pearl gourami as a model for asynchronous multi‐batch spawning fish.  相似文献   

20.
Two experiments were conducted in earthen ponds to evaluate the effect of dietary protein concentration and feeding rate on weight gain, feed efficiency, and body composition of channel catfish. In Experiment 1, two dietary protein concentrations (28% or 32%) and four feeding rates (≤ 90. ≤ 112, ≤ 135 kg/ha per d, or satiation) were used in a factorial arrangement. Channel catfish Ictalurus punctatus fingerlings (average size: 27 g/fish) were stocked into 0.04-ha ponds at a rate of 24,700 fish/ha. Fish were fed once daily at the predetermined maximum feeding rates for 282 d (two growing seasons). In Experiment 2, three dietary protein concentrations (24, 28, or 32%) and two feeding rates (≤ 135 kg/ha per d or satiation) were used. Channel catfish (average size: 373 g/fish) were stocked into 0.04-ha ponds at a rate of 17,300 fish/ha. Fish were fed once daily for 155 d. In both experiments, five ponds were used for each dietary treatment. Results from Experiment 1 showed no differences in total feed fed, feed consumption per fish, weight gain, feed conversion ratio (FCR), or survival between fish fed diets containing 28% and 32% protein diets. As maximum feeding rate increased, total feed fed, feed consumption per fish, and weight gain increased. There were no differences in total feed fed, feed consumption per fish, or weight gain between fish fed at ≤ 135 kg/ha per d and those fed to satiation. Fish fed the 28% protein diet had a lower percentage carcass dressout and higher percentage visceral fat than fish fed the 32% protein diet. Dietary protein concentrations of 28% or 32% had no effect on fillet protein, fat, moisture, and ash. Feeding rate did not affect FCR, survival, percentage carcass dressout, or fillet composition, except fillet fat. As feeding rate increased, percentage visceral fat increased. Fish fed at ≤ 90 kg/ha per d had a lower percentage fillet fat than fish fed at higher feeding rates. In Experiment 2, dietary protein concentration or maximum feeding rate did not affect total feed fed, feed consumption per fish, weight gain, FCR, or survival of channel catfish. Feeding rate had no effect on percentage carcass dressout and visceral fat, or fillet composition. This was due to the similar feed consumption by the fish fed at the two feeding rates. Fish fed the 24% protein diet had lower carcass dressout, higher visceral fat and fillet fat than those fed the 28% or 32% protein diet. Results from the present study indicate that both 28% and 32% protein diets provide satisfactory fish production, dressed yield, and body composition characteristics for pond-raised channel catfish fed a maximum rate of 90 kg/ha per d or ahove.  相似文献   

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