Cyto-architectural Alterations in the Corpuscles of Stannius of Stinging Catfish Heteropneustes fossilis after Exposure to a Botanical Pesticide (Nerium indicum)

Background: This investigation describes the cyto-architectural alterations observed in the corpuscles of Stannius of stinging catfish Heteropneustes fossilis after treatment with a botanical pesticide Nerium indicum. Methods: Heteropneustes fossilis were subjected to 11.27 and 2.81 mg/L of Nerium indicum leaf extract over short- and long-term exposure periods, respectively. Blood was collected for calcium analysis and corpuscles of Stannius (CS) gland were fixed on 24, 48, 72 and 96 h in the short-term experiment and after 7, 14, 21, and 28 days in the long-term experiment. Results: Serum calcium levels decreased from 48 h to 96 h. CS remains unaffected till 72 h. After the 96-hour treatment, increased granulation was observed in AF- positive cells. Nuclear volume of these cells exhibited no change throughout the short-term treatment. Slight increases in nuclear volume of AF-negative cells were recorded after 96 h. Nerium indicum caused decreases in serum calcium levels of H. fossilis from day 14 to 28. CS exhibited no alterations up to 14 days of exposure. AF-positive cells of CS depicted increased granulation after 21 days of treatment. Nuclear volume of these cells exhibited a slight decrease from day 21 to 28. Heavy accumulation of AF-positive granules was observed and few degenerating cells were noticed. Nuclear volume of AF-negative cells increased after 21 and 28 days of treatment. Vacuolization and degeneration occurred in certain places. Conclusion: It is inferred from the present study that the botanical pesticide Nerium indicum induced severe changes in the corpuscles of Stannius of catfish.