Effect Of Dietary N-3HUFA Or Choline Levels On Growth Performance,Serum Biological Parameters And Immunity Of Litopenaeus Vannamei

The experiments were conducted to investigate the effects of dietary n-3HUFA levels or choline levels on the growth performance,body composition,enzyme activity in liver,biological parameters in serum,related gene expression of juvenile Litopenaeus vannamei.The brief summary are as follows.1.The aim of this study is to determine the optimal n-3HUFA levels of Litopenaeus Vannamei.Six isonitrogenic and isolipidic diets with 0.24%,0.53%,0.86%,1.25%,1.58%,1.97% n-3 HUFA were used to feed Litopenaeus vannamei for8 weeks.Intial body weigh was 0.14 ± 0.00 g.The results showed that the weight gain rate(WGR)and specific growth rate(SGR)showed a trend of increasing first and then decreasing with the increasing of n-3HUFA level,reaching the maximum in the0.86% group,which was significantly higher than that of 1.97% group(P<0.05).With the increasing of n-3 HUFA level,FCR showed a trend of decreasing first and then increasing,reaching the minimum in the 0.86% group,which was significantly lower than that of 1.97% group(P<0.05).The level of feed n-3HUFA had no significant effect on SR and HIS(P>0.05).The results of body composition showed that there was no significant difference in moisture,crude protein(CP)and crude ash(CA).Ether extract(EE)showed a tendency of rising first and then decreasing,reaching the peak in the 1.25% group.ACP activity was not affected by dietary n-3HUFA levels(P>0.05),and superoxide dismutase(SOD)activity and MDA content both increased first and then decreased.SOD activity reached the peak in the 0.86% group,and the MDA content in the 1.25% group was the highest and significantly higher than that of the 0.24% and 1.97% groups(P<0.05).The activity of alkaline phosphatase(AKP)decreased first.After the increase,the 0.86% group had the lowest activity.Catalase(CAT)activity gradually decreased.As the level of dietary n-3 HUFA increased,the serum high-density lipoprotein(HDL-C)content gradually increased,the content of low-density lipoprotein(LDL-C)and triglyceride(TG)and total cholesterol(T-CHOL)gradually decreased.The contents of total protein(TP),aspartate aminotransferase(AST)and alanine aminotransferase(ALT)increased first and then decreased.T-CHOreached the highest level in the 0.86% group,and the TP,AST,and ALT levels were highest in the 1.25% group.After falling,the activity of PO rose and reached the lowest value in the 0.86% group.The genes expression were significantly affected by dietary n-3HUFA levels.The expression of FAS was gradually decreased.PL showed the decreasing tend after the first rise.Based on WGR,the n-3HUFA levels in diet for Litopenaeus vannamei determined by broken-line model was 0.79%.2.The aim of this study is to determine the optimal choline levels of Litopenaeus Vannamei.Six isonitrogenic and isolipidic diets with 0?1000?2000?3000?4000 and 5000 mg/kg choline were used to feed Litopenaeus vannamei with initial weight of 0.4±0.00 g for 8 weeks.The results showed that WGR,SGR and SR showed a steady tend after the first rise with the increase of choline levels,and reached the maximum value in the 3000mg/kg group.FCR showed a stable trend after decreasing,reached the minimum value in the 3000mg/kg group.There were no significant differences between each groups of HSI(P>0.05).The effect of dietary choline levels on moisture and crude protein of Litopenaeus vannamei was not significant(P>0.05),and crude lipid showed a decreasing trend;ash reached the maximum and minimum value in 2000 mg/kg and control groups respectively.The hepatopancreas glutathione content of Litopenaeus vannamei showed a rise trend after the first downward with the increasing of dietary choline levels,which reached the minimum in the 3000mg/kg group and significantly lower than that of the control group and 1000mg/kg groups(P<0.05),MDA showed a decreasing trend.There was no significant effect of choline levels on SOD activity(P>0.05).With the increasing of dietary choline levels,the content of ALT and AST decreased gradually in the serum of Litopenaeus vannamei,and the content of TG and T-CHOL increased gradually.The content of TP showed a steady tend after the first rise,and the maximum value was reached in 3000mg/kg group.Based on WGR,the choline levels in diet for Litopenaeus vannamei analysis was 2965.91mg/kg.