Abstract: The aim of this study was to examine the effect of cadmium on antioxidant properties in Schizothorax prenanti. Fishes were randomly divided into four groups, including control (0 mg·L^-1 Cd), low Cd concentration group (0.05 mg·L^-1), medium Cd concentration group (0.1 mg·L^-1), and high Cd concentration group (0.25 mg·L^-1). All groups were exposed for 14 days to measure antioxidant indices and biochemical indices of liver and serum. The results showed that the content of malondialdehyde (MDA) in the liver of S. prenanti was significantly increased (P<0.05) in all tested groups than those in the control, but the activity of alkaline phosphatase (ALP) was decreased (P<0.05). The liver superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and glutathione (GSH), triglyceride (TG) levels ofS. prenant were significantly decreased (P<0.05) at the low concentration of Cd compared with the control. The activities of liver aspartate aminotransferase (AST), alanine aminotransferase (ALT), acid phosphatase (ACP), superoxide dismutase (SOD) and the levels of triglyceride (TG), total cholesterol (TC), nitric oxide (NO) in S. prenanti were significantly increased (P<0.05) in the medium concentration of Cd than those in the control, whereas glutathione peroxidase (GSH-Px) activity was significantly decreased (P<0.05). The liver alanine aminotransferase (ALT), acid phosphatase (ACP) activities and nitric oxide (NO), total cholesterol (TC) levels were significantly increased (P<0.05) at high concentration of Cd than those in the control, but superoxide dismutase (SOD), aspartate aminotransferase (AST) activities and glutathione (GSH) level inS. prenanti were significantly decreased (P<0.05). Compared with the control, the serum malondialdehyde (MDA) level and nitric oxide (NO) level in S. prenant increased (P<0.05) in all test groups, the level of glutathione (GSH) was significantly decreased (P<0.05), the serum glutathione peroxidase (GSH-Px) activity ofS. prenanti was significantly decreased (P<0.05) at the medium and high concentrations of Cd. The serum superoxide dismutase (SOD) activity inS. prenantiwas significantly increased (P<0.05) at low concentration and decreased at high concentration of Cd. These results indicate that cadmium concentrations invoke a stress response in S. prenanti, which has caused the change of antioxidant indices and biochemical indices in liver and serum.

Key words: Schizothorax prenanti, cadmium, antioxidant index, biochemical index.