Effects Of Soybean Meal Replacement By Mixed Plant Protein On Growth,Immune Ability And The Gene Expression Of Growth Hormone / Insulin-like Growth Factor-I In Liver Of Yellow River Carp (Cyprinus Carpio)

Using the experimental methods of animal nutrition and molecular biology tools,this study was conducted to investigate the effects of soybean meal replacement by mixed plant protein on growth,immune ability and the gene expression of growth hormone / insulin-like growth factor-I in Yellow River carp(Cyprinus carpio).The results will provide an important theoretical basis for aquaculture.All 450 fish(initial mean weight 23.38±0.04 g)with good health condition were randomly distributed into 15 water-circulated tanks at a stocking density of 30 fish per tank.All fish were divided into 5 treatments with 3 replicates.The soybean meal of the basic formula feed had been replaced by mixed vegetable protein 0%,25%,50%,75% or 100%.The fish were fed in the automatic water-circulated system through the experiment period of 60 days.The results are as follows:1.The weight gain and specific growth rate of 50% replacement level were significantly higher 18% than that of the control group(P<0.05).The weight gain rate of 100% replacement level were significantly lower 7% than that of the control group(P<0.05).There was no significant effect on the growth performance of the carp(P>0.05)under the 25% and 75%replacement level.The mixed plant protein replacing soybean meal did not affect the visceral somatic index and fatness of the carp(P>0.05).2.The mixed plant protein replacing soybean meal did not affect the serum total protein,blood glucose,total cholesterol and alkaline phosphatase activity of the Yellow River carp(P>0.05).The serum uric acid,total triglyceride,aspartate aminotransferase and alanine aminotransferase of 100% replacement level were significantly higher than that of the control group(P<0.05).3.The mixed plant protein replacing soybean meal did not affect the whole fish body composition of the Yellow River carp(P>0.05).4.There was no significant effect on the activities of serum superoxide dismutase and lysozyme in the carp under the 25% and 50% replacement level(P>0.05),but,the activities of75% and 100% replacement level were significantly lower than that of the control group(P<0.05).There was no significant effect on the content of malondialdehyde(MDA)of serum in the carp under the 25% and 50% replacement level(P>0.05),however,it showed a trend of reduce with the increase in the proportion of the replacement.5.The contents of serum GH/IGF-I in Yellow River carp was significantly affected by the100% replacement level(P<0.05),but no difference in that of the 25%,50% or 75%replacement level(P> 0.05).The gene expression of GH and IGF-I in the liver of Yellow River carp was significantly affected by the 75% or 100% replacement level(P<0.05),but no difference in that of the 25% or 50% replacement level(P> 0.05).The results showed that the growth performance of the Yellow River carp was improved when the proportion of mixed plant protein replacing soybean meal was 50%.The contents of serum superoxide dismutase,lysozyme,malondialdehyde,GH/IGF-1and the gene expression of GH/IGF-I in the liver of Yellow River carp had not been affected.