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1.
An 8‐week trial was conducted to compare the efficacy of a chelated copper (Cu) with the inorganic Cu (CuSO4), in the diet of Japanese sea bass (Lateolabrax japonicus). Six diets were prepared based on two basal diets (semi‐purified or practical) at two Cu inclusion levels (0 and 4 mg kg?1 from or chelated‐Cu), accordingly named as S0, SI4, SM4, P0, PI4 and PM4 respectively. Each diet was fed to quadruplicate groups of Japanese sea bass (initial weight: 65.0 ± 0.03 g) during the trial. Fish fed practical diets had higher feed intake, specific growth rate, protein efficiency rate (PER), liver Cu accumulation, liver Na+K+‐ATPase and plasma alkaline phosphatase, but lower hepatosomatic index than the groups fed semi‐purified diets (P < 0.05). Higher PER was exhibited by fish fed chelated‐Cu diets than that of fish fed CuSO4 diets (P < 0.05). Although liver Cu accumulation was significantly higher in fish fed practical diets,, liver Cu content increased significantly with increasing dietary copper levels only in fish fed semipurified diets. Chelated‐Cu has higher efficiency than CuSO4 when fed in practical diets. Poor growth performance of fish fed semipurified diets might induce underestimating the nutrient requirement of Japanese sea bass.  相似文献   

2.
A total of 720 Nile tilapia fingerlings were allocated to four treatments and used to investigate the effects of zinc oxide supported on zeolite (Z‐ZnO) on growth performance and intestinal function. The basal diet (control) was not supplemented with zinc and contained 60 mg Zn kg?1. The other three groups were added 30 mg Zn kg?1 to the basal diet, in which zinc was supplemented as Z‐ZnO, Z + ZnO (mixture of zeolite and ZnO) or ZnSO4, respectively. As compared to the control, supplemental Z‐ZnO improved (P < 0.05) specific growth rate, protein efficiency ratio (PER) and survivor ratio; increased (P < 0.05) villus‐height‐to‐crypt‐depth ratio and transepithelial electrical resistance; decreased (P < 0.05) mucosal‐to‐serosal flux of dextran 4 kDa; and improved (P < 0.05) intestinal activities of protease, amylase, lipase and alkaline phosphatase. Fish fed with Z‐ZnO had higher (P < 0.05) specific growth rate and PER, and better intestinal barrier function than those fed with ZnSO4 or Z + ZnO. The zinc concentrations in whole body and vertebrae were not affected by dietary treatments. The results indicated that Z‐ZnO improved intestinal morphology, barrier function and digestive enzyme activities. Such changes in intestinal health in the presence of Z‐ZnO might contribute to its improvement in growth performance.  相似文献   

3.
A 9‐week feeding trial was carried out with juvenile Jian carp (Cyprinus carpio var. Jian) to study the effects of dietary phosphorus on growth, body composition, intestinal enzyme activities and microflora. Quadruple groups of juvenile Jian carp (7.17 ± 0.01 g) were fed practical diets containing available phosphorus 1.7 (unsupplemented control), 3.6, 5.5, 7.3, 9.2 and 11.0 g kg?1 diet to satiation. Feed intake, specific growth ratio and feed efficiency were the lowest in fish fed the basal diet (P < 0.05). Body moisture, protein, lipid content and ash were all significantly affected by dietary available phosphorus levels (P < 0.05). Activities of trypsin, amylase, Na+, K+‐ATPase, alkaline phosphatase and gamma‐glutamyl transpeptidase were improved with increasing dietary phosphorus levels. Intestinal Aeromonas and Escherichia coli decreased with increasing dietary phosphorus up to 3.6 and 5.5 g kg?1 diet respectively (P < 0.05), while Lactobacillus increased with the increasing dietary phosphorus up to 9.2 g kg?1 diet (P < 0.05). These results suggested that phosphorus could enhance intestinal enzyme activities of juvenile Jian carp and the minimum dietary available phosphorus requirement for SGR of juvenile Jian carp (7.2–63.8 g) was 5.2 g kg?1 diet.  相似文献   

4.
A 60‐day experiment was carried out to study the effects of vitamin C [ascorbic acid (AA)] on the growth, digestive enzyme activities and intestinal microbial population. Diets with six levels (0.0, 21.4, 45.1, 69.5, 93.6 and 142.1 mg AA kg?1 diet) of supplemental ascorbyl polyphosphate were fed to juvenile Jian carp (Cyprinus carpio var. Jian) (12.63±0.02 g). The specific growth rate (SGR), feed efficiency and productive protein value were significantly improved with increasing AA levels up to 45.1 mg AA kg?1 diet (P<0.05). The hepatopancreas and muscle AA concentrations were increased with increasing dietary AA levels up to 69.5 and 45.1 mg kg?1 diet respectively (P<0.05). The activities of intestinal trypsin, chymotrypsin, lipase, α‐amylase, Na+, K+‐ATPase, alkaline phosphatase, gamma‐glutamyl transpeptidase and creatinkinase were all positively affected by the AA supplementation (P<0.05). Intestinal Lactobacillus and Bacillus were increased with increasing AA levels up to 45.1 mg AA kg?1 diet (P<0.05), while intestinal Escherichia coli decreased with increasing AA levels up to 45.1 mg AA kg?1 diet (P<0.05). In conclusion, AA improve the digestive capacity and intestinal microbial population of Jian carp, and the dietary AA requirement for SGR of juvenile Jian carp was 40.9 mg AA kg?1 diet.  相似文献   

5.
The present experiment was conducted to quantify dietary copper (Cu) requirement for juvenile yellow catfish Pelteobagrus fulvidraco. The six experimental diets were formulated to contain the graded levels of CuSO4·5H2O (0, 0.005, 0.01, 0.02, 0.04 and 0.08 g kg?1 diet respectively) providing the actual dietary copper values of 2.14 (control), 3.24, 4.57, 7.06, 12.22 and 22.25 mg Cu kg?1 diet respectively. Each diet was fed to triplicate groups of yellow catfish (initial body weight: 3.13 ± 0.09 g, means ± SD) in an indoor static rearing system for 7 weeks. Fish fed the diet containing 3.24 mg Cu kg?1 diet had the highest weight gain and specific growth rate, but they were not significantly different from that of fish fed the 4.57 and 7.06 mg Cu kg?1 diets (P > 0.05). The poorest feed conversion rate, the lowest protein efficiency ratio, the lowest hepatosomatic index and viscerosomatic index were observed in fish fed the diet containing the highest Cu content diet (P < 0.05). Condition factor showed no significant differences among the treatments (P > 0.05). Proximate composition of fish body was significantly affected by dietary copper level (P < 0.05). Cu contents of whole body and liver increased with dietary Cu levels (P < 0.05), but muscle Cu content remained relatively stable (P > 0.05). Analysis by the second‐order regression of SGR and linear regression of whole‐body Cu retention of the fish indicated that dietary Cu requirements in juvenile yellow catfish were 3.13–4.24 mg Cu kg?1 diet.  相似文献   

6.
A total of 1200 juvenile Jian carp (Cyprinus carpio var. Jian) (8.76 ± 0.02 g) were fed diets containing graded levels of histidine at 2.3 (unsupplemented control), 4.4, 6.3, 8.6, 10.8 and 12.7 g kg?1 diet for 60 days to investigate the effects of histidine levels on growth performance, body composition, intestinal enzymes activities and microflora. Specific growth rate (SGR), feed efficiency, protein efficiency ratio, protein productive value, body protein content and lipid content of fish were lowest in fish fed the basal diet (P < 0.05). Activities of glutamate‐pyruvate transaminase in muscle and hepatopancreas, trypsin, chymotrypsin, amylase, lipase activities in intestine and hepatopancreas, and Na+, K+‐ATPase, creatine kinase, alkaline phosphatase, γ‐glutamyl transpeptidase activities in three intestinal segments were improved by dietary histidine (P < 0.05), whereas glutamate‐oxaloacetate transaminase activities and plasma ammonia content followed an opposite trend. The amounts of Lactobacillus, Escherichia coli and Aeromonas were significantly affected by dietary histidine levels (P < 0.05). These results suggested that histidine could improve growth and enhance intestinal enzymes activities of juvenile Jian carp. The dietary histidine requirement of juvenile Jian carp (8.76–68.02 g) based on SGR was 7.8 g kg?1 diet or 2.38 g 100 g?1 protein by quadratic regression analysis.  相似文献   

7.
A 60‐day feeding trial was carried out with juvenile Jian carp (Cyprinus carpio var. Jian) to study the effects of myo‐inositol (MI) on the growth, digestive enzyme and intestinal microbial population. Diets with seven levels of inositol (163.5, 232.7, 384.2, 535.8, 687.3, 838.8 and 990.3 mg MI kg?1 diet) were fed to Jian carp (initial weight 22.28±0.07 g). Per cent weight gain (PWG) was improved with increasing inositol levels up to 535.8 mg MI kg?1 diet (P<0.05), and plateaued (P>0.05). The protein production value, lipid production value and ash production value were increased with increasing dietary inositol levels up to 384.2, 838.8 and 838.8 mg MI kg?1 diet respectively (P<0.05). Although intestinal protein content and trypsin activity were not affected by inositol levels (P>0.05), chymotrypsin, lipase and amylase activities in intestine were the lowest for fish fed the MI‐unsupplemented diet (P<0.05). Alkaline phosphatase, Na+, K+‐ATPase, γ‐glutamyl transpeptidase and creatinkinase activities in the intestine were increased with an increase in the inositol levels up to 384.2–687.3 mg MI kg?1 diet (P<0.05). Intestinal Aeromonas hydrophila and Escherichia coli decreased with an increase in the levels of dietary inositol up to 232.7 and 687.3 mg MI kg?1 diet respectively (P<0.05), while Lactobacillus in the intestine increased with an increase in inositol levels up to 990.3 mg MI kg?1 diet (P<0.05). In conclusion, inositol improved growth, digestive capacity and intestinal microbial population of juvenile Jian carp, and the dietary inositol requirement for PWG of juvenile Jian carp is 518.0 mg MI kg?1 diet.  相似文献   

8.
Columnaris disease is an important bacterial disease of commercially grown channel catfish, Ictalurus punctatus. Copper sulphate (CuSO4) has been shown to be therapeutic and prophylactic as a water treatment for columnaris disease. Copper is an essential dietary component in animal feeds and CuSO4 is typically included in base diets; a study was conducted to evaluate whether fish feed supplemented with additional CuSO4 at 0, 40 and 80 mg kg?1 of diet and fed at a daily rate of 3% body weight would affect survival to columnaris disease. Results indicate fish fed the copper‐supplemented diet for 2 weeks significantly increased survival following F. columnare challenge. This increase appeared to be dose‐dependent. The mean per cent survival (±SEM) for fish fed the base diet (unsupplemented) for 2 weeks and then challenged was 2.0% ± 1.1. Fish fed the base plus 40 mg CuSO4 kg?1 had a mean survival of 22.0% ± 11.0. Fish fed the base plus 80 mg CuSO4 kg?1 had a mean survival of 29.3% ± 13.4. The mean per cent survival for fish fed the base diet for 4 weeks and then challenged was 28.3% ± 9.0. Fish fed the base plus 40 mg CuSO4 kg?1 for 4 weeks had a mean survival of 12.5% ± 6.3. Fish fed the base plus 80 mg CuSO4 kg?1 for 4 weeks had a mean survival of 40.5% ± 8.1. There was a significant effect after 4 weeks with fish fed the base plus 80 mg CuSO4 kg?1 mg not with 40 mg kg?1.  相似文献   

9.
To study the effects of manganese on growth performance, digestive and absorptive abilities, as well as the antioxidative capacity in the hepatopancreas and intestine, young grass carp (Ctenopharyngodon idellus Val.) (264 ± 1 g) were fed diets containing graded levels of manganese at 3.65 (control), 8.62, 13.48, 18.24, 22.97 and 27.86 mg kg?1 diet for 8 weeks. Per cent weight gain (PWG) and feed intake were the poorest in fish fed the basal diet (P < 0.05). The activities of trypsin, lipase and alkaline phosphatase in the intestine were significantly enhanced with dietary manganese level at 13.48 mg kg?1 diet (P < 0.05). Additionally, in the hepatopancreas and intestine, the protein carbonyl and malondialdehyde contents were the lowest in fish fed the diet with dietary manganese level at 13.48 mg kg?1 diet (P < 0.05), while the anti‐hydroxyl radical capacities, manganese superoxide dismutase (MnSOD), glutathione peroxidase and glutathione‐S‐transferase activities were significantly enhanced with dietary manganese level at 13.48 mg kg?1 diet (P < 0.05). Moreover, the catalase activity and glutathione content in the intestine were the highest in fish fed the diet with dietary manganese level at 18.24 mg kg?1 diet (P < 0.05). These results indicated that optimum dietary manganese promoted growth, enhanced the digestive and absorptive abilities, and improved the antioxidative capacity in young grass carp. Based on the quadratic regression analysis for PWG and intestinal MnSOD activity, the manganese requirements for young grass carp with the initial body weight of 264 g were 16.91 and 18.21 mg kg?1 diet respectively.  相似文献   

10.
This study investigated the effects of phenylalanine on growth, digestive and absorptive ability and antioxidant status of young grass carp (Ctenopharyngodon idella). Young grass carp were fed diets containing 3.4 (basal diet), 6.1, 9.1, 11.5, 14.0 and 16.8 g phenylalanine kg?1 diet with a fixed of 10.7 g tyrosine kg?1 diet for 8 weeks. Percent weight gain (PWG), feed efficiency and feed intake of fish were the lowest in fish fed the basal diet (P < 0.05). Trypsin, lipase and amylase activities in the hepatopancreas, and antioxidants including glutathione contents and glutathione reducase activities in the hepatopancreas and intestine were all the highest in fish fed 11.5 g phenylalanine kg?1 diet (P < 0.05). Trypsin, chymotrypsin and amylase activities in whole intestine, and creatine kinase, Na+, K+‐ATPase and alkaline phosphatase activities in the proximal intestine, and superoxide dismutase activities in the hepatopancreas and intestine were all the highest when phenylalanine at level of 9.1 g kg?1 diet (P < 0.05). In conclusion, phenylalanine improved growth, digestive and absorptive ability, and antioxidant capacity of young grass carp. The phenylalanine requirement of young grass carp (256–629 g) based on PWG was 10.4 g kg?1 diet or 3.44 g 100 g?1 protein.  相似文献   

11.
A 60‐day feeding trial was carried out to investigate the effect of iron on growth, body composition and digestive enzyme activities. Diets with seven levels of iron (53.9, 90.0, 115.6, 146.1, 176.0, 215.8 and 266.0 mg iron kg?1 diet) were fed to Jian carp (initial weight 11.4 ± 0.0 g). Per cent weight gain (PWG), feed efficiency (FE) and protein efficiency ratio were the lowest in fish fed the basal diet (P < 0.05). Body protein content was increased with the increasing iron levels (P < 0.05), but moisture, lipid and ash of fish were not significantly affected by dietary iron levels (P > 0.05). Activities of trypsin, lipase, α‐amylase, Na+, K+‐ATPase, alkaline phosphatase and gamma‐glutamyl transpeptidase were improved with increasing dietary iron levels. Serum iron were significantly enhanced with dietary iron levels up to 146.1 mg iron kg?1 diet, and plateaued. In conclusion, iron improved digestive enzyme activities of juvenile Jian carp and the dietary iron requirement for serum iron of juvenile Jian carp (11.4–64.0 g) was 147.4 mg iron kg?1 diet with ferrous fumarate as the iron source.  相似文献   

12.
A total of 1400 juvenile Jian carp (Cyprinus carpio var. Jian) (7.72 ± 0.02 g) were fed seven purified diets containing 0.010 (basal diet), 0.028, 0.054, 0.151, 0.330, 1.540 and 2.680 mg biotin kg?1 for 63 days to investigate the effects of biotin on growth, body composition, intestinal enzyme activities and microbiota. Specific growth rate (SGR), feed intake, feed efficiency and protein retention value were the highest when dietary biotin level was 0.151 mg kg?1 diet. Crude protein, lipid and ash content of fish carcass improved with increasing dietary biotin levels up to 0.054, 0.151 and 0.028 mg kg?1 diet, respectively (P < 0.05). Intestinal folds height, trypsin, chymotrypsin, lipase, amylase, alkaline phosphatase, Na+, K+‐ATPase, γ‐glutamyl transpeptidase and creatinekinase activities increased with dietary biotin levels up to 0.151–0.330 mg kg?1 diet (P < 0.05). Intestinal Aeromonas and Escherichia coli significantly decreased with increasing dietary biotin up to 0.151 mg kg?1 diet, while Lactobacillus and Bacillus significantly increased with dietary biotin levels up to 0.054 and 0.151 mg kg?1 diet, respectively. In conclusion, biotin could improve digestive and absorptive ability of fish, and the dietary biotin requirement for SGR of juvenile Jian carp (7.72–32.67 g) was 0.15 mg kg?1 diet.  相似文献   

13.
This study investigated the effects of valine on growth, intestinal enzyme activities and microflora in juvenile Jian carp (Cyprinus carpio var. Jian). A total of 1200 fish with an average initial weight of 9.67 ± 0.03 g were fed diets containing 5.3 (unsupplemented control), 8.7, 11.8, 14.9, 18.7 and 20.1 g valine kg?1 diet for 60 days. Results indicated that the specific growth rate, feed efficiency, body protein and lipid content of fish were significantly improved by the dietary valine (P < 0.05). The hepatopancreas weight and activities of trypsin, amylase, lipase, chymotrypsin, glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) took the similar trends. Similarly, the optimum levels of dietary valine induced increases in the intestinal length, weight, folds height and activities of alkaline phosphatase, gamma‐glutamyl transpeptidase and creatine kinase. In contrast, the trends of muscle GOT activity and plasma ammonia content were opposite. Intestinal Aeromonas, Escherichia coli, Lactobacillus and Bacillus were changed by dietary valine supplementations. The dietary valine requirement for Jian carp (9.67–76.4 g) based on SGR was 13.7 g valine kg?1 diet (4.0 g valine 100 g?1 CP). Together, these results indicated that valine improved fish growth, digestive and absorptive ability.  相似文献   

14.
D. Xie  D. Han  X. Zhu  Y. Yang  J. Jin  H. Liu  S. Xie 《Aquaculture Nutrition》2017,23(5):1104-1112
A nine‐week feeding experiment was conducted in flow‐through system with gibel carp (43.8 ± 0.2 g) to study the effects of dietary available phosphorus (P) on growth, phosphorous digestibility and intestinal enzyme activities. Seven semipurified diets were formulated to contain 0.8 (the basal), 2.4, 3.6, 6.1, 7.4, 10.1 and 15.8 g available phosphorus kg?1 diet. The results showed that specific growth rate and feed efficiency increased with increasing dietary available P from 0.8 to 7.4 g P kg?1. Fish body ash increased with increasing dietary available P, while moisture, protein content or energy content had no difference. Total phosphorus waste discharging (TPW) increased with increased dietary phosphorous. Plasma glucose was higher in the fish fed with 7.4 g kg?1 P. Plasma triglycerides was lower in fish fed diets containing 6.1–10.1 g kg?1 P. No significant effects were observed in plasma P and Ca (p > .05). The activities of intestinal amylase, lipase and trypsin showed no difference, while AKP and Na+, K+‐ATPase activities decreased with increasing dietary available P. In conclusion, based on the regression between specific growth rate (SGR), P retention efficiency, feed efficiency (FE) and dietary available P, the available P requirements for on‐growing gibel carp were 10.69, 8.22 and 6.72 g kg?1, respectively.  相似文献   

15.
A total of 900 juvenile Jian carp (Cyprinus carpio var. Jian) (7.99 ± 0.02 g) were fed diets containing graded levels of xylanase at 220 (unsupplemented control), 650, 1070, 1480, 1810 and 2470 U kg?1 diet for 10 weeks to investigate the effects of xylanase levels on growth performance, intestinal enzyme activities and microflora. The per cent weight gain, feed efficiency, protein efficiency ratio, protein production value, lipid production value, ash production value, calcium production value and phosphorus retention ratio were significantly improved with increasing levels of xylanase up to a point, and thereafter declined (P < 0.05). The activities of trypsin, chymotrypsin, lipase and amylase in the hepatopancreas and intestine, activities of alkaline phosphatase, Na+, K+‐ATPase, creatine kinase and γ‐glutamyl transpeptidase in three intestinal segments were improved by dietary xylanase (P < 0.05). The amounts of Lactobacillus, Escherichia coli and Aeromonas were significantly affected by dietary xylanase levels (P < 0.05). In conclusion, xylanase supplementation improved growth performance, enhanced intestinal enzyme activities and influenced the balance of intestinal microflora of juvenile Jian carp. The optimal level of xylanase in juvenile Jian carp (7.99–99.16 g) based on PWG was 1259 U kg?1 diet by the quadratic regression analysis.  相似文献   

16.
In this study, we replaced fish meal with peanut meal (PM) in isonitrogenous and isolipidic diets for Pacific white shrimp at inclusion levels of 0, 70, 140, 210, 280 and 350 g kg?1. The diets were hand‐fed to three independent groups of shrimp three times a day over a 6‐week period. Shrimp fed PM diets at a level of 280 g kg?1 or higher had lower per cent weight gain compared with those fed the basal diet, whereas shrimp fed PM diets at 140 g kg?1 or higher had a lower feed utilization and protein efficiency ratio compared with shrimp fed the basal diet. The feeding rate in shrimp fed PM diets at 350 g kg?1 and the survival and protease activity in shrimp fed PM diets at 210 g kg?1 or higher were lower than that in shrimp fed the basal diet. Diets containing 280 g kg?1 or higher of PM caused an increase in the whole‐body moisture content of the shrimp, but decreased whole‐body protein and ash contents compared with the basal diet. Nutrient digestibility was lower or tended to be lower in shrimp fed a PM diet compared with those fed the basal diet. The activities of peroxidase and acid and alkaline phosphatases in plasma decreased with increasing levels of PM inclusion up to 210 g kg?1. Superoxide dismutase activity decreased at dietary PM levels of 280 g kg?1 or higher. Aflatoxin B1 residue in the muscle was not affected by any of the treatments and remained low. The data suggest that up to 140 g kg?1 of PM could be included in practical diets for Pacific white shrimp.  相似文献   

17.
《Aquaculture Research》2017,48(4):1767-1777
A feeding trial was conducted to evaluate the effects of replacing soybean meal (SBM) with rubber seed meal (RSM) on digestive enzyme activity, nutrient digestibility and retention in juvenile tilapia (Oreochromis niloticus × Oreochromis aureus). Five isonitrogenous and isoenergetic diets were formulated with 0 (control), 100, 200, 300 and 400 g kg−1 RSM replacing graded levels of SBM respectively. Each diet was randomly assigned to triplicate groups of 30 fish (initial average weight 5.2 g) per aquarium in a rearing system maintained at 29 ± 1°C for 8 weeks. The hepatic protease and lipase activities gradually decreased with increasing dietary RSM level, but no significant differences were observed among the low inclusion level (0–200 g kg−1) groups. The apparent digestibility coefficients of dry matter, crude protein, crude lipid and ash showed a similar trend as the hepatic protease and lipase activities. The retentions of protein and individual essential amino acid (except lysine, threonine and leucine) in fish fed diet with 200 g kg−1 RSM were similar to those in fish fed the control diet. These results indicate that dietary RSM inclusion level up to 200 g kg−1 did not markedly affect the digestive enzyme activity, nutrient digestibility and retention in tilapia, whereas these were depressed by the inclusion of 400 g kg−1 RSM.  相似文献   

18.
The utilization of plant‐based diets in fish is limited by the presence of anti‐nutrients, which bind to dietary nutrients and reduce their bioavailability. Exogenous enzyme supplementation may alleviate the effects of anti‐nutrients and improve feed utilization. In this study, a commercial multi‐enzyme Natuzyme50® was added to a kikuyu‐based diet at a rate of 0 (control), 0.25, 0.5, 0.75 and 1.00 g kg?1 DM. Each diet was fed to triplicate groups of Oreochromis mossambicus for 60 days. All fish fed diets containing Natuzyme50® had higher (P < 0.05) growth performance compared with those fed the control diet. Fish fed the diet containing 0.50 g kg?1 had the best growth performance, highest protein digestibility and the highest levels of digestive enzyme activities. When Natuzyme50® was supplemented above 0.50 g kg?1 in the diet, growth performance and enzyme activities decreased. The improved growth performance observed with Natuzyme50® supplementation was attributed to the presence of enzymes such as cellulase, xylanase and phytase in the cocktail that are not naturally produced by fish. The presence of these enzymes released bound nutrients that would have not been available to the fish. Natuzyme50® supplementation also increased (P < 0.05) the activities of endogenous enzymes, improving the efficacy of the digestive process. The optimal dietary level of Natuzyme50® for optimal growth performance in O. mossambicus was 0.62 g kg?1 DM feed. Cost benefit analysis indicate that adding up to 0.5 g Natuzyme50® kg?1 in the diet results in higher profits as the increased growth attained offset the additional cost of Natuzyme50®.  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 effect of dietary inclusion of different levels of fermented macroalga, Enteromorpha prolifera, on the growth performance, digestive enzyme activities and serum non‐specific immunity of red tilapia (Oreochromis mossambicus × Oreochromis niloticus). Fish were fed the control diet or the five diets supplemented with fermented E. prolifera for 7 weeks (diets 1–5 containing 10, 20, 30, 40 and 50 g kg?1 of fermented E. prolifera respectively). The results showed that the percentage weight gain and specific growth rate (SGR) improved significantly in fish fed diets 3, 4 and 5, and regression analysis showed SGR reached the maximum in fish fed diet containing 37 g kg?1 fermented E. prolifera, while the feed conversion ratio reduced significantly in fish fed diets 2, 3, 4 and 5, and regression analysis showed it reached its minimum in fish fed diet containing 41 g kg?1 fermented E. prolifera. The pepsin, erepsin, gastric amylase, intestinal amylase, gastric lipase and intestinal lipase activities in fish fed diets 2, 3 and 4 were higher significantly than the control, with the exception of the pepsin activity in fish fed diet 4. The serum total superoxide dismutase, lysozyme, acid phosphatase and alkaline phosphatase activities enhanced significantly in fish fed diets 3 and 4. In conclusion, fermented E. prolifera had positive effects on the growth performance, digestive enzyme activities and serum non‐specific immunity of red tilapia and the recommended dose of fermented E. prolifera is 37–41 g kg?1 in the diet of red tilapia.  相似文献   

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