Impact of Acute Lethal and Chronic Sublethal toxicity of Phorate on Succinate Dehydrogenase activity in the Fresh Water Fish Cyprinus carpio

Abstract

The present study is aimed to investigate the acute and chronic toxicity stress of phorate, induced alterations in the activity levels of Succinate dehydrogenase (SDH), a vital enzyme of citric acid cycle that catalyses the reversible oxidation of succinate to fumarate. Freshwater fish Cyprinus carpio (C. carpio) were exposed to acute lethal toxicity (LC 50 /96 hours -0.71 ppm/l) of Phorate (ALTP) for one day and 4 days and chronic sublethal toxicity (one-tenth of the LC 50 /96 hours -0.071 ppm/l) of Phorate (CSTP) for 1, 7, 15 and 30 days. After the completion of stipulated exposure period the SDH enzyme activity levels were estimated in the vital organs of fish such as gill, liver, muscle, kidney and brain. The activity of SDH in all the organs of the fish exposed to phorate decreased at 1 and 4 days of exposure in acute toxicity in the order, day 1>4. The decrease was more at day 4 than at day 1. In the fish exposed to chronic toxicity of phorate (CTP), in the activity of SDH from day 1 to day 7 there was increase in the decrement but from day 7 to day 30 it was regressed in all the organs of the fish in the order, day 1>7<15<30. The differences in the SDH activity between controls and experimental were found to be statistically significant (P<0.05). The present study indicates the phorate induced alterations in the activities of carbohydrate metabolic enzyme caused significant metabolic effect on the physiological consequences.