Botanical pesticide, azadirachtin attenuates blood electrolytes of a freshwater catfish Heteropneustes fossilis

The present study was aimed to investigate the effects of purified neem extract azadirachtin on the blood electrolytes of Heteropneustes fossilis for short- and long-term. In short-term exposure the fish were subjected to 0.8 (i.e. 80%) of 96 h LC50 value of azadirachtin (41.89 mg L−1) for 96 h. In long-term exposure the experiment was performed for 28 days by using 0.2 (i.e. 20%) of 96 h LC50 value of azadirachtin (10.47 mg L−1). Fish were sacrificed (anaesthesized with MS 222) from control and experimental (azadirachtin) groups after 24, 48, 72, and 96 h in short-term exposure and after 7, 14, 21, and 28 days in long-term experiment. Blood samples were analyzed for calcium and inorganic phosphate levels. Acute exposure of azadirachtin caused a progressive decrease in the serum calcium levels after 48 h in fish H. fossilis which persists till the close of the experiment (96 h). The serum inorganic phosphate levels remained unaffected till 72 h in the azadirachtin exposed fish. After 96 h the levels exhibit a decrease. Chronic azadirachtin treatment caused a decrease in serum calcium levels at day 14. This decrease continued till the end of the experiment. The serum phosphate level of the azadirachtin treated fish decreased on day 14 and 21. However, on day 28 the levels were close to the normal values.

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► Heteropneustes fossilis were subjected to azadirachtin (purified neem extract).
► The experiment was conducted for short-term (96 h) and long-term (28 days).
► Serum calcium and phosphorous were analyzed.
► Hypocalcemia and hypophosphatemia were observed at different exposure periods.