Sublethal Effect of Benzo[a]pyrene (B[a]P) on Oxidative Stress and Antioxidant Enzymes in the Mud Crab Scylla serrata

Under various severe environmental conditions, marine organisms can suffer from oxidative stress. In the mud crab, the sub-lethal effect of benzo[a]pyrene (B[a]P) using environmentally realistic concentrations (10 ppb and 20 ppb) on oxidative stress and antioxidant defenses was studied. For oxidative stress, levels of Thiobarbituric Acid (TBARS) and carbonyl protein (CP) were determined. After 30 days of B[a]P exposure, the tissues contained considerably more CP and TBARS. The tissues of crab exposed to sublethal level of B[a]P for 30 days showed decrease in antioxidant defense enzymes, including superoxide dismutase (SOD) and catalase (CAT). Under B[a]P exposure, SOD and CAT activities were decreased considerably in the hepatopancreas. The glutathione S transferase (GST) increased in the hepatopancreas due to B[a]P exposure. The current study found a strong link between oxidative stress and antioxidant defenses in crab exposed to B[a]P. Overall, the results show that hepatopancreas is the most sensitive component to oxidative damage, implying that Scylla serrata could be employed as a bioindicator of organic pollution exposure by evaluating antioxidant enzyme activities.