Changes in the Leucocyte and Serum Biochemistry in Clarias gariepinus (Burchel) Exposed to Sublethal Lead Choride

Clarias gariepinus fingerlings were chronically exposed to sublethal concentrations of lead ( 0.00; 0.10 and 0.40 mg/L) as lead chloride for twenty eight days in the laboratory. The changes in the leucocytes and serum biochemical parameters (glucose, protein and total cholesterol) of the fish were determined every seven days for 28 days in a renewable static bioassay system. At the end of the study, these parameters were significantly (p < 0.05) elevated in the treatment groups when compared with the control. There was pronounced leucocytosis in the lead-exposed fish when compared with the control. The lymphocytes and the basophils were the most dominant agranulocyte and granulocytes, respectively. The magnitude of increase was influenced by both duration of exposure and concentration. The fish exposed to lead were significantly (p<0.05) hyperglycaemic and hypercholesteremic. The serum protein concentration was also significantly (p< 0.05) increased in the treatment groups when compared with the control. These changes are indications of stress imposed on the fish by lead and could be used as indices of lead poisoning. Keywords: Clarias, lead, hyperglycaemia, cholesterol, protein, leucocyt