The effect of dietary selenium levels on growth performance, antioxidant capacity and glutathione peroxidase 1 (GSHPx1) mRNA expression in growing meat rabbits

This study investigated the effect of different levels of dietary selenium (Se) on growth performance, antioxidant capacity and mRNA expression of glutathione peroxidase 1 (GSH-Px1) gene of meat rabbits from weaning to 2 months. A total of 120 growing rabbits that weaned at 30 days were randomly divided into five groups according to average body weight, with 24 rabbits in each group. Each group was fed with a diet containing 0.08, 0.24, 0.41, 0.59 and 0.70 Se mg/kg diet (dry matter (DM) basis), respectively. There was a 7-day adaptation period and a 23-day experimental period. The results showed that the dietary Se levels affected the average daily gain (ADG, P=0.0025) and the feed/gain ratio (F/G, P=0.0064). Deposition of Se in the liver increased with Se intake (P<0.0001). The dietary Se levels affected glutathione peroxidase activity (GSH-Px, P<0.0001), superoxide dismutase activity (SOD, P=0.0465), total antioxidant capacity (T-AOC, P=0.0406), malondialdehyde concentration (MDA, P=0.0004) and the expression of GSH-Px1 gene (P<0.0001) in the liver. A linear effect of dietary Se levels on the catalase (CAT) activity in the liver was obtained (P=0.0088). The dietary Se levels affected the serum GSH-Px and CAT activities (P=0.0124, 0.0156, respectively). There were no differences (P>0.05) on the serum SOD activity, T-AOC and MDA concentration among the treatments. It is concluded that optimal level of dietary Se for growth and antioxidative parameter in meat rabbits from weaning to 2 months is 0.24–0.41 mg/kg DM.