Effects Of Different Lipid Sources And Fatty Acids On Growth,Digestive Enzyme Activity And Fatty Acid Composition In Juvenile Chinese Mitten Crab,Eriocheir Sinensis

Chinese mitten crab(Eriocheir sinensis)is widely distributed in China.It is very important in Chinese aquaculture product varieties.This study was conducted to determine the effect of different lipid source and fatty acids on growth,digestive enzyme activity and fatty acid composition in juvenile Chinese mitten crab.For eriocheir sinensis in the compound feed fish oil replacement,and provide the scientific guidance the application of feeds for Chinese mitten crab.Different lipid source feeding experiment is from 2015 August 25 to December 15,breeding experiments were conducted for 112 days;different fatty acids feeding experiment is from August 29,2016 to December 15,breeding experiments were conducted for 107 days,location to Shanghai ocean university breeding base.Five diets were formulated to contain different amounts of fish oil,soybean oil and linseed oil.The control feed(Group F1)was formulated with 6% fish oil,whereas the other 4 experimental diets were formulated by 6% soybean oil(Group F2),6% linseed oil(Group F3),3% fish oil and 3% soybean oil(Group F4),3% fish oil and 3% linseed oil(Group F5).The juvenile crabs(with initial body weight 2.15±0.10g)were random divided into Group F1,Group F2,Group F3,Group F4 and Group F5.Twelve juvenile crabs were individually stocked in plastic tanks as a group.After the experiment,juvenile crabs were weighed and measured shell length,shell width,calculate each growth related indicators.After 112 d,weight gain and specific growth rate of Group F5 was significantly higher than that of other groups.No significant difference was observed in molting interval and hepatosomatic index(HSI).Analysis of digestive enzyme profiles from hepatopancreas revealed positive correlation between enzyme activity and lipid sources: tryptase activity of Group F1 was significantly higher than that of other groups;pepsin activity of Group F3 was significantly higher than that of other groups;lipase activity of Group F1;Group F2 and Group F4 were significantly higher than that of other two groups;different diet had no significant effect on amylase activity.In composition of fatty acid in hepatopancreas,C20:2n6 in group F2 is significant higher than other groups;C18:3n3 in group F3 is significant higher than other groups;C20:5n3 and C22:6n3 in group F1 is significant higher than other groups;In composition of fatty acid in muscle,in HUFA,C20:4n6,C20:5n3,C22:6n3 and HUFA in group F1 is significant higher than other groups;C18:2n6 in group F2 is significant higher than other groups;C18:3n3 in group F3 is significant higher than other groups.Four diets were formulated to contain different amounts of fatty acid oil.whereas the 4 experimental diets were formulated by 6% LOA oil(Group A1),6% LNA oil(Group A2),6% EPA oil(Group A3)and 6% DHA oil(Group F4),The juvenile crabs(with initial body weight 1.69±0.10g)were random divided into Group A1,Group A2,Group A3,and Group A4.Twenty juvenile crabs were individually stocked in plastic tanks as a group.After 112 d,weight and shell length,shell width of A2 group is higher than A1,A4 and A4 group,but no significant difference.There were no significant differences between groups of specific growth rate.A3 group has the highest survival rate,F4 group the lowest survival rate.A2 group is highest on hepatosomatic index,A4 group is minimum,but no significant difference(P > 0.05).In terms of feed coefficient,A3 group is best,A1,A2 and A4 group feed coefficient.No significant differences between groups on molt speed.In terms of digestive enzymes,A3 and A4 group crabs trypsin activity was significantly higher than other two groups,tryptase activity of F2 group is significantly lower than A1 group;A2 group pepsin activity is higher than other groups,and it is significant,difference between other groups was not significant;No significant difference between groups of lipase activity;No significant difference between groups of amylase activity.A3 and A4 group superoxide dismutase(SOD)activity was higher than the other two groups.In terms of fatty acid composition,especially PUFA unsaturated fatty acids,it is a big difference between groups,C18:2n6 of A1 is significantly higher than other groups;C18:3n3 in A2 group is significantly higher than other groups;C20:5n3 in A3 group of content is significantly higher than other groups;C22:6n3 in A4 group is significantly higher than that of other groups,and the composition of fatty acid in the muscles is similar to hepatopancreas.