Effects of dietary Rhodiola rosea on growth, body composition and antioxidant capacity of white shrimp Litopenaeus vannamei under normal conditions and combined stress of low-salinity and nitrite

An 8-week feeding trial followed by an acute combined stress of low-salinity and nitrite were designed to examine the effects of Rhodiola rosea on growth, body composition and antioxidant capacity of the white shrimp Litopenaeus vannamei. Shrimp (3.60 ± 0.03 g) were randomly allocated to 4 groups, with 3 replicates per group and 30 shrimp per replicate. The dietary groups were given as follows: control and diets containing R. rosea (300, 1000 and 3000 mg kg−1). Antioxidant capacity including total antioxidant status (TAS), activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) as well as gene expression of GSH-Px and CAT in hepatopancreas of shrimp was analysed at the end of feeding trial and again during the combined stress. The results showed that supplemental R. rosea had no significant impacts on growth and whole body composition of shrimp. There was significant effect of R. rosea supplementation dose and times on the antioxidant status parameters of L. vannamei. R. rosea (3000 mg kg−1) significantly improved the resistance of L. vannamei against the combined stress of low-salinity and nitrite, as indicated by the significant higher activities of TAS, GSH-Px and CAT (P < 0.05), as well as by the higher transcript levels of GPx and CAT gene (P < 0.05).