ABSTRACT
This study aimed to determine the effects of sub-lethal concentrations of cadmium (CdCl₂) on some haematological and biochemical parameters in 172 specimens of Clarias gariepinus. Fishes were captured from Manzala Lake, Egypt. They were acclimatized and fed with commercial fish diet for one month before starting the experiment. After determination of  LC50, Two experimental groups were exposed to two sub-lethal concentrations (10% and 30% of LC₅₀) of cadmium chloride along with control group. Fishes from different experimental groups were sacrificed after 60 days of exposure. Haematological parameters including erythrocytes, Hb, PCV, thrombocyte, leucocytes, and differential count of WBCs were estimated. Also, some biochemical parameters such as sodium, potassium, calcium, glucose, total protein, albumin, AST,ALT, ammonia, urea, uric acid, total bilirubin, creatinine, total lipids, cholesterol, triglycerides and cortisol and oxidative stress enzymes such as GSH, CAT, SOD, and MDA were measured. Group treated with 10 % of LC₅₀ of Cdshowed significantly lower concentrations of Hb, thrombocytes and SOD activity and significantly higher concentrations of eosinophil, MDA, and triglyceride. On the other hand, group of 30 LC₅₀ of Cd showed a significantly lower concentration of sodium and significantly higher activities of CAT, ALT and ammonia concentrations. The investigated two sub-lethal concentration ( 10 % and 30% of LC₅₀ of Cd ) groups showed a significantly lower activity of GSH and lower concentrations of potassium and cholesterol, besides these showed a significantly higher concentrations of uric acid and creatinine. Serum calcium, glucose, albumin, AST, urea and total lipids did not show any significant differences in the estimated treatment concentrations.