Impact of zinc on haematological parameters of freshwater fish, channa punctatus (bloch.)

The effects of sublethal concentration (4.42 mg L-l) of zinc on haematological alterations were investigated in freshwater fish Channapunctatus for 20, 40 and 60 days respectively. Result of the treated groups showed significant decrease in RBC count, Hb content, packed cell volume and mean cell haemoglobin concentration when compared to the control with increase in exposure period. On the contrary, the WBC count, mean corpuscular volume and mean corpuscular haemoglobin concentration were significantly increased. Both decreasing and increasing haematological characteristics of blood cells of Zn toxicity are mainly with time dependent effects. The alterations of haematological profile in zinc exposed fish might be due to the pathological consequences like haemolysis, anaemia and haemodilution.