The reduction of CuSO₄ toxicity in common carp (Cyprinus carpio Linnaeus, 1758) after pre-exposure to CaCO₃
2019
Bahrekazemi, Masoumeh | Ghasemzadeh, Akram
Appropriate usage of CuSO₄ as a herbicide with no toxicity mainly depends on water calcium hardness. This study aims to investigate the effect of initial exposure to CaCO₃ for the reduction of CuSO₄ toxicity in Cyprinus carpio (Linnaeus, 1758). One group of 300 fish (6 ± 0.05 g) were placed in a tank containing 200 mg.L¯¹ of CaCO₃ for 2 weeks while another group of 300 fish was maintained at normal conditions. All 600 fish were then exposed to CuSO₄ at 0.0,1.5, and 3.0 mg.L¯¹ for 60 days so that the fish weight, length and condition factor decreased significantly at increasing CuSo₄ with higher values seen in the fish pre-exposed to calcium (P < 0.01). The highest mortality was observed in 3 mg.L¯¹ of copper treatment without calcium exposure. The feed conversion ratio was elevated with an increase copper concentration. Also, the red and white blood cells, haemoglobin, and haematocrit decreased significantly (P < 0.05) at increasing copper concentration in the group that were pre-exposed to calcium. The amount of copper in muscle was elevated at increasing copper concentration, but was less in the group pre-exposed to CaCO₃. Thus, preexposure to CaCO₃ could reduce copper toxicity, especially at low concentrations of CuSO₄.
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