Changes in selected blood indices of common carp after acute exposure to cadmium

Abstract

Haematocrit, red and white blood cell count, phagocytic index, and viability of lymphocytes were studied in common carp exposed for 3 h to 10 mg dm-3 of cadmium. Hematocrit value and RBC count were elevated in all Cd-exposed (n=10) and control fish (n=10), compared to those sampled directly from the rearing tank (non-stressed). This finding indicates that the changes were caused mainly by manipulation stress, and no clear effect of cadmium on red blood cell was observed. White blood cell count was lowered after 48 and 96 h from the end of Cd exposure suggesting an immunological suppresion. Phagocytic response was significantly (P < 0.05) depressed in all stressed fish, and showed also some cadmium-induced elevation, up to 48 h from the end of the exposure. Later a decrease was observed. Preliminary results of lymphocyte viability analysis suggest some supression in 96 h. Only 6 out of 10 fish survived 96 h after the end of exposure which indicates disturbances in physiological functions in fish which were not clearly expressed in their blood.