Determination of Acute Toxicity and the Effect of Sub-Lethal Concentration of Quinalphos on Protein and Lipid Peroxidation in <i>Oreochromis niloticus</i>

Abstract

Quinalphos is an organophosphate used in agriculture that is considered to have potential hazardous effects on nontarget organisms. The present study was designed to determine the median lethal concentration (LC50) of quinalphos (an organophosphate pesticide) on the fish, Oreochromis niloticus, for 96 hours. The LC50 value of quinalphos on Oreochromis niloticus for 96 hours was determined as 3.65 μl/L. The study also focuses on the immediate effect of exposure to sub-lethal concentrations of quinalphos on protein and lipid peroxidation rate after 24 hours in brain and muscle tissues. Protein was found to be decreasing while lipid peroxidation rate increased in both tissues after 24 hours of exposure. By the estimation of antioxidant enzymes Superoxide Dismutase (SOD) and Catalase (CAT) activity, it was also identified that quinalphos is capable of impairing the antioxidant defense mechanism of the non-target organism and thereby increase the oxidative stress.