| In order to study the feasibility of Enzymatic peptide as a protein source for partial replacement of fish meal(FM)in diets of Scophthalmus maximus.L,three experiments were conducted.1.The purpose of this experiment is to study the effect of enzymatic peptides instead of fish meal on the growth performance,digestive indicators,immune indicators,liver proteomics and intestinal flora of turbot.450 turbot(Scophthalmus maximus.L)with an initial body weight of(10.32±0.26)g,uniform in size and strong in physique were randomly divided into 5 groups,with 3 replicates in each group and 30 fish in each replicate.Five groups of tests were instead of 0(control),8%,16%,24%and 32%of fish meal respectively,and were recorded as D0,D8,D16,D24 and D32.The test period is 56d.The results showed that the weight gain,survival rate,specific growth rate,feed coefficient,liver-body ratio,fatness and visceral-body ratio of turbot had no significant effect when the substitution level of poultry by-product peptides for fish meal was 8%and16%(P>0.05).The crude fat content of whole fish and the crude fat content of back muscle were significantly lower than those of the control group when the level of Hydrolyzed Peptides replacing fish meal exceeded 8%(P<0.05).The activities of total antioxidant capacity,pepsin and trypsin in D0 and D8 groups were significantly higher than those in D24 and D32 groups(P<0.05).The activities of alanine aminotransferase,glutamic oxaloacetic aminotransferase and malondialdehyde in D0 and D8 groups were significantly lower than those in D24 and D32 groups(P<0.05).The activities of glutamic-pyruvic transaminase,glutamic-oxaloacetic transaminase,complement C3,complement C4 and the contents of urea nitrogen and malondialdehyde in D0 and D8 groups were significantly lower than those in D24 and D32 groups(P<0.05).The total antioxidant capacity,superoxide dismutase activity,total protein,triglyceride,total cholesterol and glucose in D0 and D8 groups were significantly higher than those in D24 and D32 groups(P<0.05).The apparent digestibility of crude protein,crude fat and dry matter increased first and then decreased.It can be concluded that the optimum level of replacing fish meal in turbot diet with enzymatic peptides from poultry by-products is 8%based on growth performance,digestion,metabolism and specific immunity.2.The purpose of this experiment was to study the effects of partial replacement of fish meal by enzymatically hydrolyzed peptides of different molecular weights on the growth performance,digestive metabolism and immune indexes of Scophthalmus maximus.L(12.15±0.03g).The experiment designed five groups of iso-n itrogen isoenergetic feed,the fishmeal group was the control group A0,and the test group was 14%1000 peptide group A1,14%1000 peptide group A2,14%full peptide group A3.Each group consisted of three replicates,each with 30 fish.The test was performed for 56 days.The results showed that there was no significant difference in weight gain rate,specific growth rate,liver-to-body ratio,and fullness in each group(P>0.05),and the feed coefficient and viscera ratio were significantly higher in the A1 and A2 groups than in the control group(P<0.05).The crude ash and fat in the back muscle of the whole fish were significantly lower than those in the control group(P<0.05).Plasma glucose,cholesterol,and triglyceride levels in the whole peptide group were significantly higher than those in the other groups(P<0.05),urea nitrogen content in the experimental group was significantly higher than the control group,and the A3 group was significantly lower than the A1 and A2 groups(P<0.05).Liver lipase content was significantly lower in the A2 group than in the A0 group(P<0.05).The content of aspartate aminotransferase in plasma was significantly higher in the A2 group than in the other groups,the alanine aminotransferase A2 group was significantly lower than in the other groups,the aspartate aminotransferase content in the liver was significantly higher in the A1 group than in the A0 group,and the alanine aminotransferase content in each experimental group was significantly higher than that of the control group.The activities of HICN,CAT,AKP,SOD,and T-AOC in plasma were significantly lower than those in the control group and the activities of HICN,CAT,and SOD in group A3 were significantly higher than those in group A1 and A2(P<0.05).The activities of AKP,LZM,and A2 in group A3 There was no significant difference(P>0.05)and it was significantly higher than the A1 group(P<0.05).The plasma MDA content in each group increased first and then decreased,and there was no significant difference between the A3 group and the A0 group(P>0.05).The liver T-AOC activity was significantly higher in the A3 group than in the other groups(P<0.05).In summary,under the conditions of this experiment,based on the growth performance,comprehensive consideration of digestion,metabolism,immunity and other indicators,small peptides and peptides with different molecular weights can replace fishmeal and fish bodies in turbot feed with a high proportion of enzymatic hydrolyzed peptides.There is no significant improvement in the effects of.3.The purpose of this experiment was to investigate the effects of bile acid on the growth performance and digestion and metabolism of Scophthalmus maximus L.(12.15±0.03g)after partial replacement of fishmeal with enzymatic peptide.Five sets of equal nitrogen and other energy feeds were designed.The fishmeal group was the control group V0.The test group was 7%peptide group V1,14%peptide group V2,7%control group V0.The test group was 7%peptide group V1,14%peptide group V2,7%peptide plus bile acid group V3,14%peptide plus bile acid group.V4.Three replicates per group,30 fish per replicate,were tested for 56 days.The results showed that there was no significant difference in specific growth rate,weight gain rate,feed coefficient,survival rate and liver-to-body ratio between the experimental groups and the V0 group(P>0.05).The fullness of each test group was higher than that of the V0 group.The crude muscle protein of V1 and V3 group was significantly higher than other groups(P<0.05).The levels of glucose,total cholesterol,triglyceride,urea nitrogen,aspartate aminotransferase and alanine aminotransferase in liver were significantly lower in V3 V4 group than in V1 V2 group(P<0.05).There was no significant difference in total bile acid content in each group(P>0.05).The crude fat,pepsin and turbot protein fat and dry matter apparent digestibility of the whole fish back muscle were significantly higher in the V3 V4 group than in the V1 V2 group(P<0.05);the lipase activity in the liver was significantly higher in the V3 group.Group V1(P<0.05)and group V4 was higher than group V2.To sum up:the addition of exogenous bile acids after replacing part of the fish meal with enzymatic peptides can promote the growth performance,fat accumulation,digestion and metabolism and immunity of turbot to a certain extent.Therefore,a high proportion of enzymatic peptides replaces fish meal protein feed and adds bile acids.The effect is better. |
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