Effect Of Dietary N-3/n-6 HUFA On Growth Performance,Body Composition,Fatty Acid Composition And Immune In Turbot(Scophthalmus Maximus)

PART1 An 8-week feeding trial was conducted in a recirculated system to study the effect of dietary n-3/n-6 HUFA ratios(D1,29.54 D2,23.04 D3,18.97 D4,9.06 D5,6.86 D6,3.87)on growth performance,the fatty acid composition of whole body and serum biochemical indices in turbot(Scophthalmus maximus).Six diets were formulated to feed six groups of juvenile turbots(mean initial weight 12.18±0.01 g),respectively.Each diet was randomly fed to triplicate groups of 35 fish per tank.Results showed that :(1)There were no significant difference on survival rate(SR)of turbot(P>0.05).With the decreasing of the dietary n-3/n-6 fatty acid ratios,the weight gain rate(WGR),protein efficiency ratio(PER)and specific growth rate(SGR)increased first,then decreased.And WGR,PER and SGR of D6 group was significantly lower than other groups(P<0.05).Lipid rate(LR)was reduced with decreasing of the dietary n-3/n-6 fatty acid ratios,and D6 group achieved 14.80,which significant lower than other grounp(P<0.05).(2)Crude protein of whole body increased at the beginning and then decreased,the highest crude protein was recorded in D2 group(P<0.05).Crude fat content decreased as the dietary n-3/n-6HUFA level decreased(P<0.05).Crude protein and crude ash of muscle of D6 group was remarkably lower than the others(P<0.05).(3)Trypsin content increased as the dietary n-3/n-6HUFA level decreased from 29.54 to 9.06 and then decreased.Lipase was increased with decreasing n-3/n-6HUFA.In considering these results,it was concluded that the optimum dietary n-3/n-6HUFA for turbot growth was(18.97~23.04).PART2 An 8-week feeding trial was conducted in a recirculated system to study the effect of dietary n-3/n-6 HUFA ratios(D1,29.54 D2,23.04 D3,18.97 D4,9.06 D5,6.86 D6,3.87)on growth performance,the fatty acid composition of whole body and serum biochemical indices in turbot(Scophthalmus maximus).Six diets were formulated to feed six groups of juvenile turbots(mean initial weight 12.18±0.01 g),respectively.Each diet was randomly fed to triplicate groups of 35 fish per tank.Results showed that :(1)Dietary n-3/n-6 fatty acid ratios also affected whole body fatty acid,such as ARA,EPA,DHA,n-3/n-6 PUFA and n-3/n-6 HUFA.ARA was increasd with decreasing of the dietary n-3/n-6 fatty acid ratios,and D6 group significant higher than other grounp(P<0.05),while EPA,DHA,n-3/n-6 PUFA and n-3/n-6 HUFA content followed the opposite pattern(P<0.05).(2)With the decreasing of the dietary n-3/n-6 fatty acid ratios,the musle fatty acid of C22:1n-9,n-3/n-6HUFA was decreased and the D6 group was significantly lower than other groups(P<0.05).(3)Whith the dietary n-3/n-6HUFA level decreased,fatty acid synthetase and glucose-6-phosphate dehydrogenase increased at the beginning and then decreased.The dietary n-3/n-6HUFA level on 9.06,fatty acid synthetase significant higher than other grounp(P<0.05).And glucose-6-phosphate dehydrogenase significant higher than other grounp(P<0.05),when the dietary n-3/n-6HUFA level on 18.97.In considering these results,it was concluded that ARA of body was positively correlated to dietary n-3/n-6HUFA level.PART3 An 8-week feeding trial was conducted in a recirculated system to study the effect of dietary n-3/n-6 HUFA ratios(D1,29.54 D2,23.04 D3,18.97 D4,9.06 D5,6.86 D6,3.87)on growth performance,the fatty acid composition of whole body and serum biochemical indices in turbot(Scophthalmus maximus).Six diets were formulated to feed six groups of juvenile turbots(mean initial weight 12.18±0.01 g),respectively.Each diet was randomly fed to triplicate groups of 35 fish per tank.Results showed that :(1)Aspertate aminotransferase,total protein,albumin and high density lipoprotein cholesterol increased at the beginning and then decreased with the developing of the dietary n-3/n-6 fatty acid ratios.(2)Lysozyme and total antioxidant capacity increased at the beginning and then decreased with the developing of the dietary n-3/n-6 fatty acid ratios.The dietary n-3/n-6HUFA level on 23.04,lysozyme significant higher than other grounp(P<0.05).And when the dietary n-3/n-6HUFA level on 18.97,significant higher than other grounp(P<0.05).Acid phosphatase and superoxide dismutase was increasd with increasing of the dietary n-3/n-6 fatty acid ratios,and 3.87 group of superoxide dismutase significant higher than other grounp expect the 6.86 group(P<0.05).And 29.54 group of glutathione peroxidase significant lower than other grounp(P<0.05).In considering these results,it was concluded that the optimum dietary n-3/n-6HUFA for turbot immune was(9.06~23.04).