Gill Damage in Clarias Gariepinus Exposed to Cypermethrin

Abstract

Cypermethrin is a synthetic pyrethroid insecticide and is used against a wide range of pests in agriculture, public health and animal husbandry. Following the exposure, cypermethrin was administered at concentration of 0.01mg/L, 0.05 mg/L and 0.1 mg/L (A-C) and the control (0.0 mg/L) in a renewal bioassay system for a period of 21 days and standard histological techniques was used for the study. Gill histological section of the 0.01mg/L treated fish showed pathological changes; proliferation of epithelial cell at the secondary lamellae, severe destruction and degeneration of the gill filament, with prominent acidophil cell. Rapid cell lysis throughout the epithelium with chronic degenerated secondary lamella (SL) and disintegrating of epithelial lining, regeneration of mucous cell in the deeper layers of epithelial lining, hyperplasia was evident in 0.05mg/L treated groups. Uncontrolled regeneration of epithelial cells (ECs)  hyperplasia,and proliferation of epithelial cell at the base secondary lamella was prominent in 0.1mg/L group. The degree of distortion of the gills was proportional to the exposure periods and concentration of the cypermethrin was found to be dose and time dependent which possibly led to asphyxiation and stress to fish

Key word: Clarias gariepinus, gill damage, cypermethrin,