Histological changes in the branchial architecture of Heteropneustes fossilis induced by fenvalerate, a synthetic pyrethroid

Abstract

The effect of sub-lethal concentrations of fenvalerate, a synthetic pyrethroid has been observed on the histoarchitecture of third gill arch of Heteroneuste5 fossilis, an air-breathing fish following 5d, 15d and 30d exposure durations by light microscopy. Initially. there was an increase in number of mucous cells on the epithelium. The secondary gill lamella,the main seat of gaseous exchange depicted invariably lengthening and curling ,rounding of tips due to accumulation of blood cells, hyperplasia of lamellar epithelium leading to clavate-globate shape, wilting of pillar cell system and scattering of blood cells. Considerable disruption to lamellae was observed on prolonged exposure to the pyrethroid. Fenvalerate induced damage to secondary gill lamella will certainly impair gaseous exchange.