HEMOTOXIC AND GENOTOXIC EFFECTS OF LEAD ACETATE AND CHLORPYRIFOSE ON FRESHWATER CAT FISH (Calarias gariepinus)

Abstract

This study was conducted to evaluate hemotoxicity and genotoxicity induced by lead acetate and chlorpyrifos in catfish (Clarias gariepinus) as a model for checking genotoxic pollutants in aquatic surroundings. Lead acetate was added by a dose of 24.4 mg/L (20% of the LC50) daily, chlorpyrifos was added by a dose of 1.65 mg/L (1/10 LC50) daily. Fish were kept in standard condition in which water temperature (25°C± 2); pH (7.6 ± 0.4) and dissolved oxygen (5.4±0.4 mg/L). Blood and liver were sampled after 4 weeks. The result revealed a significant reduction of RBCs count, Hb, hematocrit in fish exposed to lead and chlorpyrifos. Furthermore, MDA level and catalase activity showed significant increase and decrease, respectively in groups exposed to lead acetate and chlorpyrifos in comparison with the control fish. Toxic effect of lead acetate and chlorpyrifos confirmed by histopathological changes in liver sections which showed marked hepatic vacuolation and parenchymal hemorrhage. DNA damage detected by comet assay also revealed a significance increase in tail length, tail DNA% and tail moment at sub-lethal concentration of lead acetate and chlorpyrifos. This study concluded that lead acetate and chlorpyrifos have hemotoxic and genotoxic effect probably through, at least in part, induction of reactive oxygen species and chlorpyrifos has more hemotoxic and genotoxic effect than lead acetate. Key words: catfish; lead acetate; chlorpyrifos; DNA damage