Abstract

The objective of this work is assessment of the toxicological effects of the organophosphorus compounds (methidathion and chlorpyrifos) and the usefulness of some parameters as bioindicators. Haematology and serum biochemistry were assayed in 15 cockrels at random age of 4 - 6 weeks. The birds were randomly assigned to 3 oral (by mouth) pulse-dose treatments of 0, 3.5 mg/kg chlorpyrifos, and 7.5 mg/kg methidathion, respectively. Haematology and serum biochemistry were used as indices of toxicosis. Significantly (P < 0.05) reduced WBC, Neutrophils and Lymphocyte counts were observed in the groups of birds dosed with chlorpyrifos and methidathion. PCV, Hb, and RBC were significantly decreased by methidathion while chlorpyrifos caused a significant increase in these parameters. Results obtained in this study also showed that methidathion and chlorpyrifos caused significant decrease in the levels of ALP, ALT, TP, and ALB. While methidathion caused a significant decrease in the level of AST reverse is the case for chlorpyrifos with respect to AST. It was also observed that both organophosphates had no significant effect on the level of BIL. The study thus showed that the evaluated parameters can serve as useful bioindicators of the sub lethal exposure to organophosphorus compounds.

Key words: Biochemistry, chlorpyrifos, methidathion, bioindicators, cockrels, haematology.