Histopathological changes in gill of Clarias batrachus induced by experimental Procamallanus infection

Abstract

Alterations in gill of Clarias batrachus induced by experimental Procamallanus infection were recorded on day 15, 30, 45 and 60. Gill of the control catfish comprised laterally compressed leaf-like filaments (primary gill lamellae) arranged alternately on either side of the interbranchial septum. Each primary filament bore a row of secondary gill lamellae on both sides perpendicular to its long axis. Primary gill lamellae consisted of a central core of cartilaginous rod, lining epithelial cells and blood vessels whereas secondary lamellae comprised a layer of flattened epithelial cells attached to the basement membrane, contractile pillar (pilaster) cell system and blood spaces (sinusoid). Thyroid follicles with homogenous eosinophilic colloid material in the lumen were also seen scattered among gill lamellae. Procamallanus infection in the catfish induced mild hypertrophy as well as hyperplasia in the epithelium lining cells of the primary and secondary gill lamellae on day 15 and 30. Marked hyperplasia and telangiectasis were observed in secondary gill lamellae of the catfish due to Procamallanus infection by day 45 and 60.