Effects of phenanthrene on hepatic enzymatic activities in tilapia (Oreochromis niloticus ♀ x O. aureus ♂)

The effects of phenanthrene (Phe) on hepatosomatic index (HSI) and hepatic enzymatic activities in hybrid tilapia (Oreochromis niloticus female x O. aureus male) were investigated via the static freshwater exposure at dosage of 50, 100, and 400 mu g/L for 4-14 d. Compared with the control group, HSI was significantly decreased (P < 0.05) at 400 mu g/L at day 14. Increased enzymatic activities (P < 0.05) were observed for catalase (CAT), glutathione peroxisase (GPx) and superoxide dismartase (SOD) at either 100 or 400 mu g/L at day 8 and 14, as well as for CAT at 50 mu g/L at day 14, except for GPx at 400 mu g/L at day 8. Ethoxyresorufin O-deethylase (EROD) activity was significantly increased (P < 0.05) at all dosage at day 4 as well as at 50 mu g/L at day 8, but significantly decreased at either 100 or 400 mu g/L at day 14 (P < 0.05). Glutathione-S-transferase (GST) activity was not affected. The results suggest that CAT, GPx, SOD and EROD, as well as HSI in tilapia may be used as the biomarkers or indexes for evaluating or monitoring the pollution of polycyclic aromatic hydrocarbons (PAHs) such as Phe.