Toxic Effects of Quinalphos on Protein Content and Growth Rate in Freshwater Teleost, Cyprinus carpio (L.)

Abstract

Organophosphate based pesticides account for a major percentage of pesticides used in domestic, agricultural and industrial applications throughout the world. They are highly popular because they are effective, non persistent and relatively less expensive. Quinalphos is a synthetic organophosphate which has become a matter of concern because of its potentiality and hazardous effect. Hence, the present investigation was designed to assess the impact of quinalphos on total protein content in the selected tissues and growth rate of freshwater fish, Cyprinus carpio. The lethal toxicity of quinalphos to the fish exposed for 96 h was found to be 2.75 ppm. For sublethal toxicity study, the fish were exposed to two concentration viz., 1/5^th of LC₅₀ (0.550 ppm) and 1/10^th of LC₅₀ (0.275 ppm) along with control as reference for 4, 8, 16 and 32 days. Decrease in total protein concentration and growth rate were observed in 4^th and 8^th day of exposure, but on 16^th and 32nd day of exposure all the values reached nearer to normal condition. The decline in total protein levels and relative growth rate at initial exposure periods may indicates the high energy demand associated with imposed quinalphos stress. Restoration of protein fractions to normal, implies that after 8 days of exposure there seems to exist an oscillatory phase in protein turnover towards a more synthetic phase leading to the establishment of recuperation and adaptation phenomena.