Biotransformation and Oxidative Stress Markers in Clarias gariepinus from Petroleum Exploration Area in Delta State, Nigeria

In this study Clarias gariepinus were collected from three sites (site A: Eku axis of Ethiope River (control site), site B: the swampy environment of Kokori-Erhoike petroleum flow station and site C: an earthen fish pond located within Kokori-Erhioke area). Biochemical analyses in serum, gill, liver, brain and muscle tissues of Clarias gariepinus (n=8/site) were performed using standard methods. Results indicated that blood reduced glutathione was significantly (p < 0.05) lower in Clarias gariepinus from sites B and C as compared with site A but elevated (p < 0.05) in the liver of fish from site B and C as compared with that of site A. Activities of glutathione S-transferase, superoxide dismutase, catalase and lactate dehydrogenase and values of malondialdehyde indicate high measure of oxidative stress in serum, gill, liver, brain and muscle tissues of fish from sites B and C as compared with that of site A. The changes observed in biochemical parameters showed that the fish were relatively under stress in their natural habitat (Erhoike swamp) and fish pond as compared with Ethiope River (Eku axis) and could be employed as biomarkers of contamination in environmental monitoring of crude oil pollutants and their metabolic changes as early warning signs of adverse effects of environmental pollution