Histopathological alterations, biochemical responses and acetylcholinesterase levels in Clarias gariepinus as biomarkers of exposure to organophosphates pesticides

Organophosphate pesticides, commonly used in large scale farming, have been found to be major contaminants in aquatic environment. Clarias gariepinus was exposed to acute and sublethal concentrations of phostoxin and DD Force to evaluate single and joint action toxicity of the organophosphates. Effects of phostoxin and DD force on antioxidant enzymes, fish organs and acetylcholinesterase levels in fingerlings and juveniles of C. gariepinus were also investigated. The lethal concentrations (96 h LC 50 ) for phostoxin and DD Force were 0.631 and 1.759 mg/l, respectively. The results obtained from the bioassay showed that phostoxin was 2.8× more toxic than DD Force after exposure of C. gariepinus . Joint action toxicity evaluations of phostoxin and DD Force showed that the interaction between the chemicals was synergistic (RTU >1). The biochemical responses in the exposed fish differed significantly ( P