Cadmium exposure of common carp, Cyprinus carpio: effects on phagocytic index Phagocytosis is one of the most important mechanisms of defence against pathogenic microorganism. The study was performed to determine the sublethal effects of cadmium on phagocytic activity in common carp. Fish (mean weight 700g) were divided in two groups, I and II. Group I was kept in cadmium free water and group II was exposed to 30ppb cadmium as CdCl2 (Merck) for 30 days. Blood samples were obtained from 15 fish of each group by puncturing the caudal vein at day 15 and 30 post-exposure with a heparinized syringe (1/4 inch needle). Phagocytic activity can be evaluated using a microscopic counting technique described by Elaine (1990) with some modifications. In the present study, we use yeast instead of formalin-killed E.coli. The results revealed that there was no significant difference between the phagocytic index in the control and exposed group (p≤ 0.05).
