Studies on the histopathological changes in selected tissues of fish Labeo rohita exposed to phenol

Histopathological changes in vital tissues like gills, liver and kidney in the fish Labeo rohita exposed for 8 days to sublethal (5.2 mgl(-1)) and lethal concentration (25.09 mg(-1)) of phenol were studied. The observed histopathological changes in the gills were epithelial hyperplasia with lamellar fusion, epithelial hypertrophy, edema, general necrosis, increased mucous production and degeneration of primary and secondary gill lamellae at sublethal (5.2 mg l(-1)) and degenerated primary and secondary gill lamellae, lamellar fusion and lamellar disorganization at lethal (25.09 mg l(-1)) concentration. In the liver, the changes include as: formation of number of vacuoles, enlargement of nuclei of some cells, enlarged sinusoids with numerous blood cells and atrophic areas at sublethal (5.2 mg I(-1)) concentration and nuclear and cytoplasmic degeneration and melanomacrophages aggregates at lethal (25.09 mg I(-1)) concentration. In case of kidney, the changes were: degeneration of proximal and distal convoluted tubule, vacuolation of renal interstitial tissue and deformation of the nuclear membrane of some cells at sublethal (5.2 mg l(-1)) and occlusion of tubular lumen, cloudy swelling degeneration and hyaline droplets degeneration at lethal (25.09 mg l(-1)) concentration.