Impact of Profenofos and Carbosulfan on Dehydrogenase activity of Freshwater fish, Labeo rohita (Hamilton)

Experiments were intended to study effects of profenofos and carbosulfan on the activities of dehydrogenase of freshwater fish, Labeo rohita. Healthy freshwater fish, Labeo rohita (Hamilton) were collected from the Nandivelugu fishfarm, India. Profenofos and carbosulfan pesticides were purchased from local pesticide store in Guntur, India, based on the preliminary lethal toxicity tests (96 hr LC50 i.e. 100 μg l-1; 1.2 mg l-1 and 1/10th 96 hr LC50 i.e.10 μg l-1; 0.12mg l-1 and) were selected as lethal and sublethal concentrations. After the acclimation, fish were exposed to lethal and sublethal concentrations in groups of 10 fish in 15 L of the test water in test chambers for 1 and 8 days. Fluctuations in succinate dehydrogenase (SDH), lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) were observed in different tissues of the experimental animal. The activity of LDH was highly elevated following profenofos and carbosulfan exposure indicating increased anaerobic respiration to meet the energy demands where aerobic oxidation is lowered. Rapid depletion of SDH activity in all tissues of fish, L. rohita treated with sublethal and lethal concentrations of profenofos and carbosulfan. When compared to their respective controls. The general reduction in SDH activity due to pesticidal stress was associated with the inhibition of mitochondrial respiratory mechanism of dearrangement on ultra-structure, architectural integrity and permeability of mitochondria. Decreased MDH activity levels due to the inhibition exerted by oxaloacetate; maybe decrease in the activity of TCA cycle dehydrogenase is consistent with the disintegration of mitochondria of CO2 formation from acetate. Both profenofos and carbosulfan intoxication exerted a profound influence on the dehydrogenase enzymes of fish L. rohita but comparatively profenofos treated fish tissues showed more deterioration when compared to carbosulfan treated fish.