Nickel induced histopathological changes in the different tissues of freshwater fish, Hypophthalmichthys molitrix (Valenciennes).

Nickel chloride, heavy metal widely used in industries was investigated in the present study for histopathological studies in silver carp (Hypophthalmichthys molitrix). Fish were exposed for 10, 20 and 30 days in sublethal concentration of nickel 5.7 mg/l. The histopathological changes were studied in the gill, liver, intestine and kidney of the nickel treated freshwater fish H. molitrix. The nickel showed a tissue specific alteration in the tissues. Mucus proliferation, fusion of the gill lamellae and hypertrophy of gill tissues were observed. Lack of normal palisade arrangement was followed by necrosis in hepatocytes. Degeneration of blood vessels, vacuolation, hypertrophy, pyknotic nuclei and lesion were observed in liver tissues. Degeneration of tubular cells, hyperplasia was observed in kidney tissues.

Impact of cadmium on food utilization of the Indian major carp, Catla catla (Ham).

Catla catla, under the sublethal stress of cadmium exhibited depletion in food utilization parameters and it was concentration dependent. Heavy metal intoxication was found to exhibit reduction in biomass.