Corpuscles of Stannius (CS) and serum calcium of Heteropneustes fossilis were studied after exposure to Chlorpyrifos-Based Commercial Formulation (CBCF) for short-term (1.76 mg L-
chlorpyrifos) and long-term (0.44 mg L
chlorpyrifos) application. The fish were sacrificed after 24, 48, 72 and 96 hours in short-term experiment and after 7, 14, 21 and 28 days in long-term experiment. Hypocalcaemia was noticed in CBCF-treated fish after both short- and long-term exposures. In CBCF-treated H. fossilis, AF-positive cells of CS exhibit increased granulation after 72 and 96 hours, the nuclear volume of these cells remains unchanged. The AF-negative cells of CS of CBCF-treated fish exhibit a slight increase in their nuclear volume after 96 hours. After 21 and 28 days, AF-positive cells of CS show increased granulation. Nuclear volume of these cells exhibited a decrease after 21 and 28 days. A few degenerating cells are also noticed. Nuclear volume of AF-negative cells of CS of CBCF-treated fish increase after 21 and 28 days.
Keywords: , organophosphate, chlorpyrifos, fish, Heteropneustes fossilis, hypocalcaemia, nuclear volume, cell degeneration, cell degeneration