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1.
This study was designed to evaluate the effects of using soybean meal supplemented with or without methionine (M) and graded levels of phytase (P) to replace high‐level (60%) fish meal in the diets for juvenile Chinese sucker. Seven experimental diets (about 430 g kg?1 crude protein on dry matter basis) were formulated from practical ingredients. The control diet (FM) was formulated to contain 400 g kg?1 white fish meal (FM), whereas in the other six diets (diets 2–7), soybean meal (SBM) was used to replace 60% fish meal with or without methionine (3 g kg ?1) and 0,500, 1000, 1500 and 2000 U kg?1 phytase (designated as SBM, SM, SMP500, SMP1000, SMP1500 and SMP2000, respectively). Results from the feeding trial indicated that SBM without any methionine or phytase supplement replacing about 60% FM significantly affected the growth of fish (P < 0.05). Weight gain of fish fed diet SM was significantly higher than the fish fed diet SBM, but still much lower than fish fed the control diet (P < 0.05). SBM with methionine and phytase supplement significantly improved the growth of fish and apparent digestibility coefficients of phosphorus compared with the groups which fed diet SBM and diet SM (P < 0.05). Weight gain of fish fed SMP1000, SMP1500 and SMP2000 had no significant difference than fish fed control diet. Furthermore, fish fed SMP1500 showed optimum weight gain and ADC of phosphorus between these three groups. This suggested that soybean meal with 3 g kg?1 methionine and 1500 U kg?1 phytase supplement could successfully replace 60% fish meal in the diet for juvenile Chinese sucker without affecting growth and enhanced the apparent digestibility coefficient of phosphorus.  相似文献   

2.
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   

3.
A basal isonitrogenous and isoenergetic plant‐based diet (Control) was supplemented with either 10 g kg?1 sodium diformate (NaDF), 4000 FTU kg?1 phytase (Phy) or a combination of both additives (NaDF + Phy). Three hundred juvenile rainbow trout with an average weight of 120 g were randomly distributed into 12 fibreglass tanks (300 L). After 65 days of trial, fish fed diets containing phytase, NaDF or the combination of both additives showed a higher growth rate (P < 0.05) compared to fish fed Control diet. NaDF increased feed intake (P = 0.032), while phytase inclusion resulted in a better feed conversion ratio (P < 0.0001) and a higher N retention efficiency (P = 0.02) compared with the Control. Apparent digestibility of P, Ca, Mg and Zn was improved by the use of phytase (P < 0.005) as well as P, Ca and Mg retention efficiency in fish (P < 0.0001). Using 4000 FTU kg?1 phytase in plant‐based diets resulted in a 13% and 50% reduction in N and P loadings, respectively. The use of NaDF in combination with phytase in a plant‐based diet for rainbow trout resulted in a higher weight gain than that when NaDF was used alone.  相似文献   

4.
Abstract.– Juvenile channel catfish Ictalurus punctatus (initial weight: 6.8 g/fish) were fed four practical diets containing 0, 250, 500, and 750 units of microbial phytase/kg and a diet containing 1% feed grade dicalcium phosphate (but no microbial phytase) under laboratory conditions for 12 wk. Fish fed the diets containing 250 units of microbial phytase/kg and above consumed more feed, gained more weight, and had a lower feed conversion ratio (FCR) in comparison to fish fed the basal diet containing no microbial phytase. Fish fed the diet containing dicalcium phosphate had intermediate weight gain and feed conversion ratio as compared to fish fed the basal diet and diets containing microbial phytase. Bone ash and phosphorus concentrations were lower for fish fed the basal diet than for fish fed other diets. No differences in weight gain, feed consumption, FCR, bone ash and bone phosphorus were observed among fish fed the diets containing various levels of microbial phytase. Fish fed the diet containing dicalcium phosphate had a lower bone phosphorus concentration than fish fed diets containing microbial phytase. Fecal phosphorus concentrations were lower for fish fed the diets containing microbial phytase than for fish fed the basal diet and the diet containing dicalcium phosphate. Results from the present study indicated that addition of 250 units of microbial phytase/kg to practical diets can effectively improve bioavailability of phytate phosphorus to channel catfish and may possibly eliminate the use of an inorganic phosphorus supplement in channel catfish diets. However, these data must be verified in trials conducted in ponds, prior to recommending removal of supplemental phosphorus from channel catfish diets.  相似文献   

5.
A feeding trial was conducted to study the effect of dietary lipid on growth performance and heat‐shock protein (HSP70 and HSP60) response of white seabass (WSB), Atractoscion nobilis. Five diets were formulated to contain 440 g kg?1 protein from 300 g kg?1 fish meal, 240 g kg?1 soybean meal and 100 g kg?1 soy protein concentrate with different levels of lipid: 100, 120, 140, 160 or 180 g kg?1. At the end of the trial, heat shock response based on HSP70 and HSP60 was measured in liver and white muscle from fish at ambient temperature and temperature shock conditions. Final weight and percent gain were significantly higher for fish fed the 100 g kg?1 lipid diet than for fish fed the rest of the diets (P ≤ 0.05). Feed conversion ratio was lowest for fish fed the 100 g kg?1 lipid diet. The HSP70 and HSP60 responses were positively correlated to dietary lipid levels following temperature shock. At ambient temperature, HSP60 and HSP70 responses in muscle and HSP60 response in liver increased with dietary lipid level. Temperature shock significantly increased the HSP response of fish in all treatments. Results of this study demonstrated that a moderate (110–120 g kg?1) level of dietary lipids would be recommended for production diets but a higher dietary lipid level may be required for optimal stress tolerance.  相似文献   

6.
A 60‐day study was conducted to determine the response of juvenile bluegill Lepomis macrochirus to seven experimental diets, formulated using a blend of alternative protein sources as a replacement for fish meal. Adequate levels (digestible basis) of energy, protein and amino acids were maintained in diets 1–6, whereas slightly lower protein and energy levels were provided in diet 7. Feed cost per tonne ranged from $ 798.9 (diet 1, 550 g Kg?1 fish meal) to $ 515.8 (diet 6, 0 g kg?1 fish meal), or to $ 507.2 (diet 7, 0 g Kg?1 fish meal). Three commercial diets were included in the study as reference diets: a high‐energy and a low‐energy trout diet, as well as a catfish diet. Quintuplicate bluegill groups (~22 g, n = 10 fish group?1) were fed the experimental diets twice daily to apparent satiation. No major differences in feed consumption, feed efficiency and growth rates were detected among the bluegill groups fed the experimental diets. Trout diets generally produced higher fish fat deposition, whereas the catfish diet produced a poorer fish growth rate relative to the experimental diets. Under the reported conditions, results indicate diet 6, comprising predominantly soybean meal and porcine meat and bone meal, to be the most economical diet for juvenile bluegill.  相似文献   

7.
A feeding trial was conducted in a recycling water system during 10 weeks to determine the optimal protein to lipid ratio in Asian red‐tailed catfish (Hemibagrus wyckioides). Six diets of two protein levels (390 and 440 g kg?1) with three lipid levels (60, 90 and 120 g kg?1) were formulated. Fish (1.96 g) were fed six diets with four replicates to apparent satiation at a stocking density of 50 fish per tank (500 L). Faeces were collected in cultured tanks at the end of the feeding trial for digestibility measurement. Significantly, improved growth performances (P < 0.01) and higher feed utilization (P < 0.001) were observed in fish fed with higher lipid diets. However, higher protein diets did not significantly improve fish growth but they reduced FCR (P < 0.001) and protein efficiency ratio (P < 0.01). Higher lipid diets also resulted in significantly increased adipose‐somatic index, carcass fat and reduced moisture of the fish. The study revealed the protein sparing effect of dietary lipid in the catfish and highest growth performance was found by fish fed 390 g kg?1 protein and 120 g kg?1 lipid diet with P/E ratio of 20.48 mg protein kJ?1. DP/DE ratio for maximal growth rate in diets was 21.48 mg protein kJ?1.  相似文献   

8.
The study was to evaluate the effects of dietary fish meal (FM) partially replaced by housefly maggot meal (HMM) on growth, fillet composition and physiological responses of juvenile barramundi, Lates calcarifera. HMM at 100, 150, 200 and 300 g kg?1 was supplemented in the basal diet to replace dietary FM protein. Basal diet without HMM supplementation was used as control. Total of five experimental diets were fed to triplicate groups of juvenile barramundi (initial weight: 9.66 ± 0.22 g) in a flow‐through rearing system for 8 weeks. Fish fed all experimental diets showed no effects (P > 0.05) on weight gain and whole body protein, lipid and moisture content. Fish fed control diet and 100 g kg?1 HMM diet had the highest (P < 0.05) hepatic superoxide dismutase (SOD) activity, followed by 150 g kg?1 HMM group, the lowest in 200 and 200 g kg?1 HMM groups. Hepatic thiobarbituric acid reactive substance (TBARS) value was the highest in fish fed 150–300 g kg?1 HMM diets, followed by 100 g kg?1 HMM group and the lowest in fish fed the control diet. Fish fed the 300 g kg?1 HMM diet had lower plasma lysozyme activity than fish fed other diets. The results indicated that up to 300 g kg?1 HMM can be used to substitute dietary FM protein without negative effect on growth. Although physiological responses were also considered, up to 100 g kg?1 HMM in barramundi diet was recommended.  相似文献   

9.
A study was conducted to estimate the optimum requirement of dietary available phosphorus for GIFT strain of Nile tilapia Oreochromis niloticus. Six purified diets were formulated to contain graded levels (0 (control diet), 2.9, 4.8, 7.6, 9.1 and 10.9 g kg?1 diet) of available phosphorus. Each diet was fed to triplicate groups of 12 fish with initial average weight (46.03 ± 2.14) g for 8 weeks. The results showed that fish fed the three lowest phosphorus diets (0, 2.9 and 4.8 g kg?1) had significantly lower weight gain rate, specific growth rate (SGR) and feed efficiency than those fed the other diets (P < 0.05). The survival rate of fish fed the control diet was significantly lower than that of the fish fed the other diets (P < 0.05). Whole body viscerosomatic index and crude lipid content decreased significantly with increasing dietary available phosphorus levels (P < 0.05), while the contents of crude ash, calcium, phosphorus in the whole body and vertebrae showed the opposite trend (P < 0.05). The blood chemistry analysis showed that dietary available phosphorus had significant effects on serum phosphorus concentration, enzyme activities of alkaline phosphatase and parathyroid hormone level. Quadratic curve analysis based on SGR indicated that the minimum dietary requirement of available phosphorus for maintaining optimal growth of tilapia was 8.6 g kg?1.  相似文献   

10.
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   

11.
The aim of this experiment was to determine the effects of dietary inclusion with mannan oligosaccharide (Bio‐Mos, Alltech, Nicholasville, KY, USA) on growth, survival, physiological and immunological conditions and gut morphology of the black tiger prawn (Penaeus monodon). Five diets supplemented with MOS at 0 g kg?1 (control diet), 1, 2, 4 and 8 g kg?1 were fed to the prawn juveniles (0.4 ± 0.06 g, total weight) for the duration of 63 days. Growth was the highest (P < 0.05) when the prawns were fed the 1 g kg?1 MOS included diet. Wet tail muscle index (Tw/B), dry tail muscle index (Td/B) and tail muscle protein (Tmp) were higher (P < 0.05) in the prawns fed MOS included diets MOS compared with the prawns fed the control diet. Total haemocyte counts (THCs) of the prawns fed MOS included diets were higher (P < 0.05) than THCs of the prawns fed the control diet. Epithelium layer and epidermal cell density of the gut of the prawns fed 1 g kg?1 and 2 g kg?1 MOS diets were better than the prawns fed the control and other MOS diets. The results imply a positive effect of dietary supplementation of 1–2 g kg?1 MOS in the culture of black tiger prawns.  相似文献   

12.
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   

13.
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   

14.
Six isonitrogenous and isocaloric semi‐purified diets were prepared with different levels of microbial levan: control (Basal), T1 (Basal + 2.5 g kg?1 diet), T2 (Basal + 5 g kg?1 diet), T3 (Basal + 7.5 g kg?1 diet), T4 (Basal + 10 g kg?1 diet) and T5 (Basal + 12.5 g kg?1 diet), fed to six groups of fish in triplicate tanks. The results of the 60 days feeding trail showed that supplementation of dietary levan significantly affected the weight gain percentage and specific growth rate of the treatment groups fed at 10 g kg?1 or more levan. Lowest feed conversion ratio (FCR) value and highest survival percentage among levan fed groups were observed with 12.5 g kg?1 incorporation (T5) and was comparable with (T4) group. Significant increase in muscle RNA level and RNA/DNA ratio was observed with the increasing dietary levan. Fish fed 12.5 g kg?1 levan had significantly higher protease, amylase and lipase activities compare with the control group. Lowest Aspartate aminotransferase (AST) activity in the liver and muscle was observed in the T5 group fed with highest level of dietary levan. Overall results conclude that dietary microbial levan incorporation at 12.5 g kg?1 could be used as potent dietary prebiotic for the culture of L. rohita juveniles.  相似文献   

15.
The present study investigated the optimum dietary protein level for the maturation of adult Pangasianodon hypophthalmus broodstock. Four isocaloric diets containing 250, 300, 350 and 400 g kg?1 of protein levels were prepared and presented to triplicate groups of fish. The fish (mean weight 770 ± 17.23 g and 712 ± 23.42 g for females and males respectively) were stocked in outdoor canvas tanks (4 m × 1 m × 1 m) at a stocking density of 20 fish/tank with a male: female ratio of 1:4. The fish were fed the test diets to satiation twice daily for 6 months. Gonadosomatic index (GSI) and fecundity were similar among fish fed dietary protein levels, higher than those fed on the 250 g kg?1. Final weight, weight gain, oocyte weight were significantly highest (P < 0.05) for the fish fed 350 and 400 g kg?1 dietary protein treatments. Only the 350 g kg?1 dietary protein treatment resulted in significantly best ovipositor diameter and % ripe egg. Amino acid levels were highest in the muscle followed by the oocyte and liver of fish fed 350 and 400 g kg?1 dietary protein levels. The present results suggested that a dietary protein level of 350 g kg?1 can be recommended for the development of P. hypophthalmus broodstock.  相似文献   

16.
This study was conducted to investigate the prebiotic effect of different Dietary Fibre Concentrates (DFC) (Mucilage =MG; Pectin = PN or β‐glucan + mannan = βg + M) on growth and somatic parameters, body composition and digestive enzyme activities of jundiá (Rhamdia quelen). After acclimation, fish (7.16 ± 0.06 g) were allocated into 24 tanks (30 fish per tank) and triplicate groups were fed with Control diet (0 g kg?1 of DFC); diet supplemented with 5 g kg?1 commercial prebiotic (CP) or diets supplemented with 5 or 10 g kg?1 diet of MG; PN or βg + M. At the end of the trial (8 weeks), growth was significantly (P < 0.05) higher in fish fed diets supplemented with DFCs and did not differ from animals supplemented with CP. The animals that were fed Control diet presented a body protein content higher compared to those supplemented with diets containing pectin or β‐glucan + mannan (P < 0.05). However, fish fed diets added with β‐glucan + mannan yielded a higher level of protein deposited in the whole body. The activity of digestive enzymes was lower in the group supplemented with Pectin. Results indicate that supplementation with DFCs in the diet had positive effects on the performance of jundiá and are prebiotic potential candidate.  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.
Six iso‐nitrogenous (410 g kg?1) diets with three levels of total phosphorus (P4, P10 and P18 g kg?1) and two levels of starch (S200 and S350 g kg?1) were fed to triplicate groups of 30 fish to evaluate whether the high level of dietary phosphorus could improve the utilization of starch. Over 8‐week‐growth trial, best weight gain (WG) and specific growth rate (SGR) (P < 0.05) were observed in fish fed the P10/S200 and P18/S200 diets. WG and SGR significantly decreased as starch levels increased whereas for P4, while lipid contents of liver and whole body, hepatosomatic index and intraperitoneal fat ratio (IPF) significantly increased. These results suggested that high dietary starch will depress the growth performance and cause lipid accumulation. Within both starch levels, fish fed diet with P4 tended to produce lower (P < 0.05) WG and SGR, and had higher (P < 0.05) values of IPF. The whole body lipid, ash, calcium, phosphorus and iron contents were significantly affected by dietary phosphorus levels. Supplied phosphorus could improve the growth and decrease the whole body lipid, but there is no more effect after the phosphorus requirement was met at 10 g kg?1.  相似文献   

19.
A 76‐day feeding trial was carried out to evaluate the effects of Lysine and Methionine supplementation on growth and digestive capacity of grass carp (Ctenopharyngodon idella) fed plant protein diets using high‐level canola meal (CM). Fish with initial average weight 103.9 ± 0.6 g were fed three extruded diets. Fish meal (FM) diet was formulated as the normal control with 40 g kg?1 FM and 300 g kg?1 CM; CM diet was prepared by replacing all FM with CM (total 340 g kg?1) without Lys or Met supplementation; CM supplement (CMS) diet was similar to CM diet but was supplemented with essential amino acids (EAA) to ensure the levels of Lys and Met similar to those in the FM diet. Feed intake, feed efficiency and specific growth rate of the grass carp fed CMS and FM diets were similar (P > 0.05), but higher than those of the grass carp fed CM diet (P < 0.05). The hepatosomatic index, relative gut length, intestosomatic index and intestinal folds height were significantly improved in fish fed FM and CMS diets as compared to CM diet (P < 0.05). Lower activities of trypsin, lipase and amylase in hepatopancreas were observed in fish fed CM diet (P < 0.05). Three hundred and forty gram per kilogram CM without Lys or Met supplementation significantly decreased trypsin, lipase and amylase mRNA levels in hepatopancreas (P < 0.05). These results indicated that the high supply of CM (340 g kg?1) in plant protein (200 g kg?1 soybean meal and 100 g kg?1 cottonseed meal) diets decreased digestive ability through decreasing digestive enzyme activities and enzyme gene's expressions of grass carp, and these side effects can be reversed by supplementing Lys and Met. Therefore, CM could be high level used in a plant protein blend‐based extruded diet for grass carp as long as EAA were supplemented.  相似文献   

20.
This study was conducted to evaluate the effects of citric acid (CA) supplementation in diet without inorganic phosphorus (P) on growth, muscle and bone composition, proteolytic activities and serum antioxidant property of rainbow trout. Six diets were designed as the negative diet without monocalcium phosphate (MCP) supplementation, the positive diet containing 10 g kg?1 MCP and CA supplementation diets with 4, 8, 12, 16 g kg?1 CA supplementation in negative diet, and then were fed to rainbow trout (113.6 g) for 60 days. Results showed that the fish fed 8 g kg?1 CA, 12 g kg?1 CA diet had higher weight gain, higher contents of crude ash and P in bone, and lower feed conversion ratio than those of fish fed negative diet (P < 0.05), and showed the similar levels as those of fish fed positive diet (P > 0.05). The proximate composition and P level of muscle were not affected by dietary CA and MCP. The proteolytic activity in intestine, but not in stomach and gastric digesta, was significantly improved by dietary CA and MCP (P < 0.05), when compared with negative control. The activities of serum superoxide dismutase of 12 g kg?1 CA and 10 g kg?1 MCP groups were significantly higher, and the malondialdehyde of 8 g kg?1 CA and 12 CA g kg?1 groups were significantly lower than those of negative control (P < 0.05). The above results indicated that the supplementation of CA could substitute the inclusion of MCP in rainbow trout diet and the supplementation level was suggested to be 8–12 g kg?1.  相似文献   

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