Effect of copper toxicity on the hemolymph factors of the Indian edible oyster, Crassostrea madrasensis (Preston)

Abstract

The Indian edible oyster, Crassostrea madrasensis collected from the backwaters of Kochi, India were exposed to three sub-lethal concentrations of copper viz. 0.1, 0.5 and 1 ppm at a salinity of 12 ppt. Modulations in different heamolymph factors such as total hemocyte count, differential hemocyte count, phagocytosis, serum protein, serum acid phosphatase, serum phenol oxidase and serum lysozyme were studied. It was found that, the lowest concentration of copper had a stimulating effect on all the parameters studied. However, at higher concentrations except serum lysozyme all the hemolymph parameters studied showed significant reduction. Although copper could act as an immunostimulant at lower doses, it significantly reduced the disease resistance of the species at concentrations above 0.5 ppm in mesohaline waters.