Effects of dietary reduced glutathione on growth performance, non-specific immunity, antioxidant capacity and expression levels of IGF-I and HSP70 mRNA of grass carp (Ctenopharyngodon idella)

Abstract

Abstract This study was conducted to evaluate the effects of dietary reduced glutathione (GSH) on growth performance, non-specific immunity, antioxidant capacity and related gene expression of grass carp ( Ctenopharyngodon idella ). Six hundred and thirty juvenile grass carp with initial body weight of 5.10 ± 0.09 g were randomly distributed into six groups with three replicates each, fed six diets containing graded levels of GSH (14.26, 112.41, 210.24, 407.45, 602.85 and 798.32 mg/kg diet) for 60 days. At the end of the feeding trail, ten fish per tank were challenged with Aeromonas hydrophila and the cumulative mortalities were recorded for 7 days. The results showed that the weight gain (WG), specific growth rate (SGR) and survival rate of grass carp, serum total protein (TP), lysozyme, alkaline phosphatase (ALP), and complement 3 (C3) levels, activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) in the liver, and liver total antioxidant capacity (T-AOC) and GSH contents, and expression levels of IGF-I and HSP70 mRNA significantly increased, while feed conversion rate (FCR), liver glutathione reductase (GR) activity and malondialdehyde (MDA) content significantly decreased with dietary GSH levels up to 407.45 mg/kg diet ( P P > 0.05). The challenge experiment showed that the cumulative mortality significantly decreased with dietary GSH contents up to 407.45 mg/kg diet ( P