Xenobiotic metabolising enzymes and antioxidant defences in deep-sea fish:: relationship with contaminant body burden

Xenobiotic metabolising enzymes, namely the cytochrome P450 monooxygenase system and glutathione S-transferase, as well as antioxidant enzymes were determined in the liver of 3 deepsea fish species (Lepidion lepidion, Bathypterois mediterraneus and Coryphaenoides guentheri). These organisms were collected from 3 stations along the NW Mediterranean, at depths ranging from 1500 to 1800 m. The enzymatic activities detected in deep-sea fish indicated the ability of these organisms to cope with pollutants and oxidative stress. Differences among the studied species may be related to habitat and diet, viz, the highest monooxygenase and antioxidant enzyme activities were observed in L. lepidion, a typical middle slope species, whereas the lowest activities were recorded for B. mediterraneus, an organism adapted to live at greater depths. Tissue concentration of persistent organochlorinated compounds, Like polychlorinated biphenyls, DDTs and hexachlorobenzene, were in the lower range of those reported for coastal fish, and significant differences among sampling stations were not observed. Overall, the obtained results contribute to the knowledge of the NW Mediterranean deepsea basin and reflect the chronic contamination of the area in terms of organochlorinated compounds, rather than the influence of coastal discharges.