摘要An 8-week feeding trial was conducted to evaluate the effects of dietary vitamin E levels on growth,antioxidant status and immune response for mud crabs(Scylla paramamosain).A total of 180 mud crabs(initial weight:24.16±1.08 g)were fed six different dietary vitamin E levels,where the analyzed vitamin E were 9.65,34.70,58.50,76.30,102.00 and 199.00 mg/kg,respectively.The results showed that crabs fed with the 76.30 mg/kg vitamin E diet exhibited significantly higher final weight(P=0.007),percent weight gain(PWG)(P=0.008)and specific growth rate(P=0.010)than those fed the diets with 9.65 and 34.70 mg/kg vitamin E.The highest activities of total antioxidant capacity in hemolymph(P=0.006)and hepatopancreas(P=0.017),and superoxide dismutase(SOD)(P=0.037)in hemolymph were observed in crabs fed the 76.30 mg/kg vitamin E diet,and crabs fed the diet with 102.00 mg/kg vitamin E showed higher activities of peroxidase(POD)(P=0.006)and a-tocopherol transfer protein(P=0.024)in he-molymph than those fed the other diets.Dietary 76.30 mg/kg vitamin E significantly up-regulated the expression of cat,gpx,prx and CytMn-sod in hepatopancreas(P＜0.01).The expression levels of genes related to pro-inflammatory factor(il-16,litaf,rab6a and relish)in hepatopancreas were significantly down-regulated and the expression level of anti-inflammatory factor related gene(tgf)significantly up-regulated in crabs fed diet with 199.00 mg/kg vitamin E(P＜0.05).Crabs fed the diet with 76.30 mg/kg vitamin E exhibited the highest percentage of survival cells in hemocytes(P=0.026).The mRNA expression level of genes related to pro-apoptotic cytokines(bax and bok)significantly down-regulated,and the mRNA expression level of anti-apoptotic cytokines related genes(pi3k,akt and bcl-2)signifi-cantly up-regulated with dietary vitamin E levels increasing from 9.65 to 76.30 mg/kg(P＜0.05).In conclusion,the quadratic regression model based on PWG indicated that the optimal requirement of vitamin E was 99.13 mg/kg for the mud crab.Moreover,dietary 58.50 and 76.30 mg/kg vitamin E inhibited the inflammatory response and improved the immune response.