Cypermethrin-induced in vivo alterations in the carbohydrate metabolism of freshwater fish, Labeo rohita

Abstract

Aspects of carbohydrate metabolism under in vivo conditions were analyzed in functionally different tissues of the freshwater fish, Labeo rohita, exposed to a lethal (LC50/96 hr = 5.24 micrograms liter-1) and sublethal concentration (0.52 micrograms liter-1) of cypermethrin for 4 days. All exposed fish exhibited a hyperglycemic condition. An increase in tissue lactate with a decrease in pyruvate, total carbohydrates, and glycogen contents was noted. Activity of lactate dehydrogenase was elevated, indicating a shift toward anaerobiosis. TCA cycle enzymes, namely succinate dehydrogenase and malate dehydrogenase, were inhibited. In most cases changes were more pronounced during a lethal exposure compared to sublethal exposure period. The data indicate that the fish has adopted a compensatory mechanism to derive energy during pyrethroid toxicosis.