Effect of chromium chloride on serum calcium and phosphate levels of stinging catfish Heteropneustes fossilis

The present study was aimed to investigate the effects of chromium chloride on the blood electrolytes of Heteropneustes fossilis for short- and long-term exposure. In short-term exposure the fish were subjected to 50% of 96-h LC50 value of chromium chloride for 96-h. In long-term exposure the experiment was performed for 30 days by using 10% of 96-h LC50 value of chromium chloride. Fish were killed on each time intervals from control and experimental groups after 24, 48, 72, and 96 h in short-term exposure and after 5, 10 15 and 30 days in long-term experiment. Blood samples were analyzed for calcium and inorganic phosphate levels. Acute exposure of chromium chloride caused a 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 remain unaffected till 48 h in the chromium chloride. At 72 h and 96 h the levels exhibit a decrease. Chronic chromium chloride caused a decrease in serum calcium levels at day 10. This decrease continues till 15 days thereafter levels tend to rise approaching control level. Serum phosphate level of the chromium treated fish decreases on day 15 and 30.