Histopathological Lesions in Heteropneustes fossilis Subjected to Acute Thiodan Toxicity

The common Indian freshwater catfish, Heteropneustes fossilis, was exposed to the 96 h-LC₅₀ (0.007-0.013 ppm) of the organochloride thiodan (endosulfan) for 4 days. The stressed fishes showed various histopathological changes. In the liver, extensive degeneration of cytoplasm, pycnosis of nuclei, and loss of glycogen was observed most commonly. Stasis of circulation and constriction of bile duct lumen was also seen frequently. In the kidney, shrinkage of glomeruli, cytoplasmic damage and epithelial desquamation in tubules, and extensive degeneration of hemopoietic stroma was commonly observed. In the intestine, the damage was comparatively negligible, the most common effect was an increased mucus cell activity leading to accumulation of mucoid exudates in the lumen.