Quinalphos Induced Antioxidant Status and Histopathological Changes in the Gill of the Freshwater Fish, Oreochromis mossambicus

To extend the knowledge about quinalphos induced antioxidant status and its related changes on the histopathology of gills, the freshwater fish Oreochromis mossambicus was chosen as a model system. Quinalphos treatment (0.5μl/ L for 30 and 60 days) decreased the activities of antioxidant enzymes with concomitant increase in the production of malondialdehyde. Increased reactive oxygen species generation coincides with the increase in the protein carbonyl in the gills of the treated fishes. Histological observation in the gill of quinalphos treated animal for 60 days showed several alterations as hypertrophy of gill arches, lifting of lamellar epithelium, degeneration of gill filament and lamellar epithelium and vasodilation in the lamellar axis when compared to the control group. These observations suggest that chronic exposure to pesticide affect the respiratory oxidative potential of the freshwater fish and this could be possibly due to quinalphos induced oxidative stress in the gill.