Effect of an Organophosphate Insecticide, Dimethoate, on Antioxidant Enzymes of the Fish Nile Tilapia, (Oreochromis niloticus) (L.)

Application of synthetic insecticides to save crops from the invasion of pest is a common practice, however unwise use of synthetic insecticides causes health and environmental concerns, including the contamination of aquatic ecosystem. Effect of dimethoate, an organophosphorus insecticide on the antioxidant activity of fresh water fish, Nile Tilapia (Oreochromis niloticus) was studied. The LC50 value of dimethoate for 96 h was calculated as 0.234 ppm. The 1/5th of 96 h LC50 value was taken as the sublethal dose. The treated fishes were scarificed and the gill, liver and kidney were collected for the antioxidant enzyme analysis. Results showed significant variations in the antioxidant enzymes of fish treated with insecticide. In the gill, SOD and catalase was found reduced (P