Sublethal effects of cadmium and copper on the blood characteristics of catfish Clarias batrachus (Linn.)

The present study was conducted to determine the effects of sublethal concentrations of CdCl 2 and CuSO 4 as a pollutant on some haematological parameters of Clarias batrachus were exposed to three sublethal levels.Sublethal concentrations used were 7.5 ppm for cadmium and 0.9 ppm for Cu.The results obtained revealed that there was significant difference in hematocrit, Exposure of Clarias batrachus to sublethal concentrations of Cd resulted in significant decrease (p < 0.05) in erythrocyte count and haemoglobin content, while there was a slight increase in case of copper.The microscopical observations showed that exposure of Clarias batrachus to sublethal concentrations of heavy metals 7.5 ppm for cadmium and 0.9 ppm for Cu resulted in some changes in the morphology of the R.B.Cs which tended to lose its ellipsoidal shape acquiring different shapes (poikilocytosis or anisocytosis).