toxic effects of cadmium on antioxidant defense systems and lipid peroxidation in acipenser persicus (borodin, 1897)

cadmium is considered as a common residue in water and sediments which could readily enter aquatic organisms. the aim of this study was to evaluate the time- and concentration-dependent changes in antioxidant enzymes (sod and cat) activities as well as concentration of mda as a bi- product of lipid peroxidation in the liver of persian sturgeon, acipenser persicus , following cdcl 2 exposure at sub-lethal concentrations for 14 days. based on the results, activity of sod and cat showed a significant increase in the fish exposed to different concentrations of cdcl 2 up to the day 7, and then their activity decreased in the fish of all treatments on the 14 th day. in all treatments, mda content significantly increased after exposure at first day until the end of the experiment. the levels of sod, cat and mda followed a concentration-dependent manner and its increase was higher in 800 µgl -1 than those of 200 µgl -1 . the results suggested that antioxidant enzymes could be used as an effective index to monitor ecotoxicological changes.