Effects of Dietary Glutathione on the Growth Performance, Skin Mucus Antioxidant Capacity, and Immune Responses of Juvenile Taimen Hucho Taimen

The effects of dietary glutathione on growth performance, skin antioxidant capacity, and immune responses and of juvenile taimen (Hucho taimen) were investigated. The experimental fish had a mean initial weight of 5.36 ± 0.13 g and were fed for eight weeks on diets containing graduated amounts of glutathione (0, 100, 200, 400, and 800 mg kg−1). After the 7 d lipopolysaccharide challenge, the immune parameters of the skin mucus, and antioxidant ability were determined. The treatment groups (400 – 800 mg kg−1) showed a higher survival rate and weight gain rate (P < 0.05). There were higher levels of skin mucus protein, lysozyme activity, and alkaline phosphate activity associated with dietary glutathione supplementation (P < 0.05). Dietary glutathione supplementation improved the minimal inhibitory concentration and antimicrobial activity of the skin mucus (P < 0.05). Fish in the treatment groups showed higher superoxide dismutase, glutathione peroxidase, and catalase activity (P < 0.05), whereas the malondialdehyde content was lower (P < 0.05) than those in the control group. Supplementary glutathione decreased the expression levels of TNF-α, IL1β, IL6, IL8 in the skin and ensured the relatively high expression levels of IκBα after lipopolysaccharide challenge. In conclusion, dietary glutathione (400 – 800 mg kg−1) improved the growth performance, decreased lipopolysaccharide-induced skin inflammatory response, indicating that glutathione has the potential anti-inflammatory effects for preventing inflammation diseases in juvenile taimen.