Effects Of Dietary N-3/n-6 Fatty Acid Requirement And Physiological Reaction Of Oriental River Prawn(Macrobrachium Nipponense)

As essential fatty acids of crustaceans,n-3 and n-6 series fatty acids have important effects on the growth performance,antioxidant capacity and lipid metabolism of crustaceans.Five isonitrogenous and isolipid diets with different n-3/n-6 fatty acid ratios 0.29,0.56,1.04,2.20 and 8.52 were formulated to feed five groups of shrimps,respectively.The purpose of this study was to study the optimal ratio of n-3/n-6 fatty acids in Macrobrachium nipponense diet,and provides reference for the development of compound feed.The research results of this experiment are showed as fllowing:1.Effects of proportions of feed n-3/n-6 fatty acids on growth and meat quality of M.nipponensisThis experiment by changing the dietary and the content of soybean oil and fish oil in proportion to adjust the dietary n-3/n-6 fatty acid ratio,Five isonitrogenous and isolipid diets with different n-3/n-6 fatty acid ratio.Eight weeks later,the results showed that:The WGR and SGR of the prawns showed a trend of increasing first and then decreasing with the increase of the proportion of n-3/n-6 fatty acids in the diet,and the highest in group 1.04(P<0.05).The proportion of n-3/n-6 fatty acids in diet had a significant effect on the CF of the prawns,and the highest in group 0.29(P<0.05).The body moisture content,FR and crude ash content of the prawns had no significant difference fed with different n-3/n-6 fatty acid ratio(P>0.05).And the CP content of the prawns was highest in the group 1.04,which was significantly different from groups 0.56,2.20 and 8.52(P<0.05).The ratio of n-3/n-6 fatty acids in the feed had a significant effect on the composition of fatty acids in the muscle of shrimp.The composition of n-3/n-6 fatty acids in shrimp muscle varies with the diet,and there is an obvious positive correlation between then(P<0.05).2.Effects of proportions of n-3/n-6 fatty acids in feed on digestive enzymes,antioxidant capacity and gene expression of M.nipponensisChanging the content of soybean oil and fish oil in proportion to adjust the dietary n3/n-6 fatty acid ratio in the diet,Five isonitrogenous and isolipid diets with different n-3/n-6 fatty acid ratio were made,to investigate the effects of dietary n-3/n-6 fatty acid ratio on digestive enzymes,antioxidant capacity and gene expression of M.nipponensis.Eight weeks later,The results showed that:Activity of AMS in M.was not affected by the ratio of feed fatty acids(P>0.05).However,the activity of Trypsin and LPS was significantly affected(P<0.05).When the ratio of n-3/n-6 fatty acids in the diet was 1.04,the Trypsin activity of the prawns was significantly higher than other group(P<0.05),and the LPS activity was significantly lower than other group(P<0.05).When the dietary fatty acids ratio was 8.52,the serum SOD activity of M.nipponensis was the highest(P<0.05),but it was not significantly different with group 2.20.Serum GPx activity and MDA content were significantly affected by the ratio of dietary fatty acids(P<0.05).GPx activity in group 1.04 was significantly higher than other groups(P<0.05).The serum MDA content of group 8.52 was significantly higher than that group of 0.29 and 1.04(P<0.05).Serum NO content in group 1.04 was significantly lower than that group of 0.29 and 0.56(P<0.05).But compared with other groups iNOS activity was the highest(P<0.05).Serum ASAFR content was the lowest in group 1.04,significantly lower than that group of 0.29,2.20 and 8.52(P<0.05).The expression of antioxidant genes of M.was significantly affected by the different proportions of fatty acids in the diet.The expression level of Hsp 60 reached its peak in group 2.20,which was significantly different from group 8.52(P<0.05).However,the expression levels of Hsp70 and Toll reached the peak in group 0.56,which was significantly different from other groups(P<0.05).In 8.52 group,Myd88s howed the highest expression and significantly higher than other groups(P<0.05).