Study On The Application Of PHFP In Feed Of Litopanaeus Vannamei

In order to study the feasibility of PHFP as a protein source for partial replacement of fish meal(FM)in diets of Litopenaeus vannamei,three experiments were conducted.The methods and results of this research are as follows:1.Five experriment diets were prepared to replace 0(control),2%,4%,6% and 8% FM of basal diet by premixed PHFP(adding coated methionine in the PHFP to reach methionine content in line with domestic FM),and corresponding named as T0,T1,T2,T3 and T4,respectively.A total of 900 Litopenaeus vannamei with the average body weight of(0.31±0.01)g were randomly divided into 5 groups with 3 replicates per group and 60 shrimps per replicate.The indoor feeding experiment lasted 8 weeks.The results showed as follows: PHFP could replace 2% to 6% of FM without causing a significant reduction in the weight gain rate,specific growth rate,protein efficiency and feed efficiency of shrimps(P>0.05).Compared with the control group,the crude fat content of whole body was significantly decreased(P<0.05)and the ash content of whole body was significantely increased(P<0.05)when the replacement level of FM with PHFP was over 2%.When the replacement level of FM with PHFP was 2%,the lipase(LPS)activity in hepatopancreas was highest among the groups,while the contents of glucose(GLU)and triglycerides(TG)in plasma were significantly decreased(P<0.05)and activity of lysozyme(LZM)in plasma was significantly increased compared with control group(P<0.05).When the replacement level of FM with PHFP was over 2%,the peroxidase(POD)activity in plasma was significntly decreased compared wih control group(P<0.05).There were no significant differences in the apparent digestibility of crude protein and crude fat,the activity of LZM,POD and total antioxidant capacity(T-AOC)in hepatopancreas(P>0.05).It follows that in this experiment condition,based on the growth performance and took into account digestive indices and non-specific immune indices,optimal replacement level of FM with PHFP in the diet for Litopenaeus vannamei is 2%.2.In order to study the effects of PHFP supplemented with different forms of methionine instead of partial FM in diets on the growth of Litopenaeus vannamei,2% of FM in basal diet group were replaced by PHFP supplemented with coated methionine and crystalline methionine to FM methionine level.The growth showed that the weight gain,specific growth rate and protein efficiency of Litopenaeus vannamei of P2 group were slightly higher than those of P1 and P0 groups,but the difference was not significant(P>0.05);the fat content of whole shrimp and muscle of P2 group were significantly lower than those of P0 and P1 groups(P<0.05),and the ash content of whole shrimp was significantly higher than that of P0 and P1(P<0.05);The activity of PPS of group P1 was significantly lower than group P0(P<0.05),and there was no significant difference between group P1 and group P2(P>0.05);There was no significant difference in the activity of digestive enzymes and the apparent digestibility of nutrients in each groups(P>0.05).The concentrations of TG,GLU,AST and ALT in the plasma of P1 and P2 were lower than those in the P0 group,but no statistical significance was attained(P>0.05).In the hepatopancreas of Litopenaeus vannamei,the activity of ALP in group P1 was significantly lower than that in P0 and P2 groups(P<0.05),and there was no significant difference in other immune indexes(P>0.05).In the hemolymph of Litopenaeus vannamei,the activity of POD in group P2 was significantly lower than that in group P1 and P0(P<0.05),while the activity of T-AOC was significantly higher than that in group P1 and P0(P<0.05).The activity of LZP in plasma in group P1 and P2 were slightly higher than that in group P0,but there was no significant difference in each groups(P>0.05).It follows that in this experiment condition,based on the growth performance and took into account digestive indices and non-specific immune indices,premixed PHFP with crystal methionine instead of 2% FM is better than premixed PHFP with coated methionine3.The Label-free quantitative protein mass spectrum dynamic analysis was used to analyze the total protein in hepatopancreas of Litopenaeus vannamei.The results show that among the common,group V has 15 protein up-regulated expression and 3 protein down-regulated expression(actin T2,skeletal muscle actin 6,alpha glucosidase)compared with group C.The up-regulated proteins included trypsin?serine collagenase 1?serpin 3?aquaporin 4?calreticulin?tetraspanin?secretory leukocyte proteinase inhibitor?tubulin alpha chain?integrin beta?NADH-ubiquinone oxidoreductase chain 3?calcium-transportig ATPase?F0-ATP synthase b-chain?alpha-amylase?chitinase?fructose 1,6-bisphosphatase,and involving carbohydrate metabolism,protein folding and transport,aerobic respiration,hydrogen ion trans membrane transport,electron transport,cell proliferation and differentiation and other biological processes.Conclusion: At the molecular level,premixed PHFP with crystal methionine substitute for 2% of FM in basal diet is optimal for growth of Litopenaeus vannamei.