Changes in biochemical and physiological responses of common carp, Cyprinus carpio L. after longterm exposure to Pb (II)

In this study, the chronic toxic effects of Pb (II) on common carp, Cyprius carpio were investigated using several biomarkers at different levels of biological functions for assessing changes in ecosystem quality. In a bioassay, common carp juveniles were individually exposed to different dose of heavy metal, Pb II (0, 0.45, 0.89, 1.34 mg.l^-1) for 28 days. Morphological indices such as hepatosomatic index, condition factor and lipid peroxidation (LPO) level and also the activities of superoxide dismutase (SOD) and catalase (CAT) were measured. These results indicated that there was significant lower condition factor in fish exposed to the highest concentration of Pb (p 0.05). The activity of hepatic antioxidant enzymes (SOD and CAT) and LPO level was significantly elevated after long-term exposure to higher concentration of Pb (p 0.05). Briefly, our findings suggested that common carp exposed to lead, develop oxidative stress, hence long-term exposure to higher concentrations of Pb could seriously affect the health status of fish.