This study reports histopatholgoical changes in the intestine of the fish Channa punctatus exposed for 30 days to sublethal doses of the water soluble fractions (WSF) of petrol (9.60 ml/L) and diesel (8.70 ml/L) fuels. WSF of petrol induced loss of normal architecture & orientation of villi which became shrunken and atrophied and exhibited interlocking arrangement. Besides, the hyperactive mucous secreting cells together with their nuclei became pyknosed and necrosed indicating signs of apoptosis. More severe nature of degenerative changes were observed under the toxicity of WSF of diesel. These were disintegrating serosa, very ill defined epithelial lining, almost structureless and detached core of mucosal fold as well as ruptured and broken villi leading to heavy exudation of mucus into the lumen. Possible explanations have been discussed and the findings led us to conclude that WSF of both petrol and diesel impair the absorptive capacity of the intestine.
This study reports the curative effects of zinc and ascorbic acid on cadmium induced histopathological changes in kidney of the freshwater cat fish Heteropneustes fossilis. Exposure of the fish to 16.14 mg/L sub lethal concentration of cadmium for 30 days induced hypertrophy of glomeruli, dilation and rupture of Bowman’s capsule and glomerular tuft, degeneration of epithelial cells lining the renal tubules, haemorrhage between tubules, hyaline degeneration of tubules, indistinct lumen, cytoplasmic vacuolation, accumulation of lipid droplets and generalized necrosis in kidney. However, 16.14 mg/L cadmium + 0.5 mg/L zinc and 16.14 mg/L cadmium + 1.25 mg/L ascorbic acid exposed fish groups revealed signs of recovery which were more progressive with ascorbic acid as evident from considerable restoration of normal size of Bowman’s capsule, structure of tubular epithelial cells and almost normal structure of renal corpuscles. Our study concludes that zinc and ascorbic acid have protective influence on cadmium toxicity in fish but higher doses than the one selected in the present case are probably needed to overcome the effects of cadmium toxicity.