Mortality, Oxidative Stress and Hepatotoxicity in Juvenile African Catfish, Clarias gariepinus Burchell, Exposed to Lead and Cypermethrin

In this study, juvenile catfish (Clarias gariepinus) were exposed to 2 mg/L Pb, 0.5 mu g/L cypermethrin, or both for 96 h. Survival ranged from 100 % in both treatments without cypermethrin, to 50 % in fish exposed to cypermethrin only or the mixture. There were significant decreases in liver lysozyme, gamma-glutamyl transpeptidase, and alanine aminotransferase activities in fish exposed to cypermethrin or the mixture. Liver aspartate aminotransferase activity (AST) showed a significant reduction after exposure to Pb or cypermethrin alone, and the effect of the mixture on AST was additive or potentially synergistic. Liver lipid peroxidation (LPO) was increased in fish exposed to the mixture compared to those exposed to cypermethrin only, indicating that Pb presence enhanced LPO caused by cypermethrin. Our study demonstrates the potential for toxic interaction between Pb and cypermethrin in fish and suggests that due to the varying responses to contaminant mixtures in our study, researchers should consider using a variety of biomarkers.