The effect of calcium carbonate pretreatment at different temperatures on reducing the toxicity of copper sulfate in common carp (Cyprinus carpio Linnaeus, 1758)

The use of copper sulfate as an algaecide in fish farms can cause poisoning in fish and harm their growth and health. Due to the effect of water calcium amount on copper sulfate toxicity, in this study, the effect of seven-day calcium carbonate pretreatment on reducing copper toxicity in common carp (Cyprinus carpio) was investigated at two different temperatures. Initially, half of the carp were raised in water which 200 mg / L of calcium carbonate was added to for one week. Then, all fish were reared at concentrations of 0, 1.5 and 3 mg /L of copper sulfate at 22 and 27 °C for 60 days. Based on the results, weight gain and condition factor decreased and the percentage of mortality and feed conversion ratio increased significantly, with increasing the amounts of copper and temperature (p < 0.05). In both groups of fish, the numbers of red and white blood cells, and the amounts of hemoglobin and hematocrit decreased with increasing copper sulfate concentration and temperature, and MCV and MCH increased. But in the case of MCHC, no clear trend was observed. Also, the positive interaction of all three parameters of pretreatment with calcium carbonate, temperature, and copper sulfate concentration was not significant only in the case of white blood cells and mortality (P>0.05). Therefore, increased copper sulfate can affect the growth efficiency, nutrition, and survival of fish, especially at 27 ° C, and pretreatment with calcium carbonate can significantly reduce the negative effect of copper sulfate in competition with copper...