Abstract
The present study was undertaken to assess the bioaccumulation potential of cadmium in liver, kidney, gills and muscles of freshwater fish, Nile tilapia Oreochromis niloticus and the changes in oxidative stress indices in liver and kidney with or without simultaneous treatment with waterborne vitamin C and rosemary leaf extract. Adult tilapia were divided into seven groups. Six groups were exposed to sublethal concentrations of Cd, three groups to 5ppm, while other three to 10ppm. Two groups from each of the Cd exposed groups were treated with Vitamin C (5ppm) and rosemary leaf extract(2.5ppm) for a period of 21 days. Cadmium concentration in liver, kidneys and gills was significantly higher in the cadmium exposed groups being invariably high in the groups exposed to 10ppm CdCl2 center dot H2O. Treatment with Vitamin C and rosemary leaf extract significantly reduced cadmium concentration in comparison to non-treated Cd exposed groups. Treatment with Vitamin C and rosemary leaf extract significantly reduced oxidative stress in Cd exposed fish as evidenced from lower concentration of lipid peroxides and reduced activity of catalase and higher activity of superoxide dismutase in liver and kidney as compared to control fish. Reduction in Cd induced oxidative stress and bioaccumulation was comparable between the two antioxidant treatments, Vitamin C and rosemary leaf extract. The key findings suggest that both the antioxidants used showed ameliorative potential to reduce tissue accumulation of Cd and associated oxidative stress in fresh water fish, Nile tilapia.