Effects of dietary vitamin E supplementation on antioxidant enzyme activities in Litopenaeus vannamei (Boone, 1931) exposed to acute salinity changes

This study examined the effects of dietary tocopheryl acetate (vitamin E) and salinity on muscle superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) activity and gill Na+/K+-ATPase activity in Litopenaeus vannamei. Three diets containing 0, 100 and 600 mg tocopheryl acetate kg-1 diet, respectively, were fed to shrimp (40-50 mg) for 35 days. Subsequently, shrimp were subjected to an acute salinity change (30[per thousand] to 5, 15, 30, and 50[per thousand]) for 24 h. Significantly (P 0.05). A similar trend was observed in Na+/K+-ATPase activity of shrimp fed the control diet. Na+/K+-ATPase activity of shrimp fed the vitamin E-supplemented diet showed no significant variation response to acute salinity changes. Supplementation of vitamin E in diet could enhance the resistance of shrimp to acute changes in salinity. However, the higher dose of vitamin E supplement was not significantly different from the moderate dose. The results demonstrated that vitamin E might have a potentially useful role as an effective antioxidant by regulating osmotic balance and resistance to salinity changes in shrimp.