Toxicological impacts of a botanical pesticide, azadirachtin on corpuscles of Stannius of stinging catfish, Heteropneustes fossilis

Abstract

Heteropneustes fossilis were subjected to 41.89 mg L−1 of azadirachtin for short-term exposure (96 h) and 10.47 mg L−1 of azadirachtin for long-term exposure (28 days). The fish were killed on 24, 48, 72 and 96 h in short-term and 7, 14, 21 and 28 days in long-term experiment. Corpuscles of Stannius (CS) were fixed on these time intervals. CS remain unchanged till 72 h in short-term azadirachtin exposure. Accumulation of granules has been noticed in the aldehyde fuchsin (AF)-positive cells at 96 h. The nuclear volume of these cells remains unchanged. The AF-negative cells of CS of azadirachtin-exposed fish exhibit a slight increase in their nuclear volume after 96 h. In long-term exposure, the CS remain unchanged up to day 14. Increased granulation in the AF-positive cells has been noticed following 21-day exposure. Moreover, the nuclear volumes of these cells show a significant decrease. Heavy accumulation of AF-positive granules and few degenerating cells are also noticed at 28 day in azadirachtin-exposed H. fossilis.