Reduction in Hepatic Microsomal P-450 and Related Catalytic Activity in Farm-Raised Red Drum

Abstract

Hepatic microsomal factors were investigated in red drum Sciaenops ocellatus, an important aquaculture and sportfish species. Constitutive and induced levels of microsomal cytochrome P-450 and P-420, catalytic activities of 7-ethoxyresorufin O-deethylase (EROD) and NADPH–cytochrome-c reductase, and the extent of membrane lipid peroxidation were compared in juvenile farm-raised and wild fish. We detected smaller amounts of active cytochrome P.450 and more cytochrome P-420, the denatured form of cytochrome P-450, in farm-raised than in wild red drum. Lipid peroxide formation was significantly higher and EROD catalytic activity was decreased in farm-raised red drum, whereas wild fish exhibited significantly higher levels of cytochrome P-450 and EROD activity. No significant alterations in NADPH–cytochrome-c reductase activity were observed in farm-raised fish. The livers from farm-raised red drum had higher levels of cellular lipid, which correlated with higher levels of lipid peroxides and were apparently associated with the loss of active cytochrome P-450. These data indicate that farm-raised fish fed a commercial, potentially lipogenic, diet may be less capable of metabolizing endobiotics, drugs, and hydrocarbon pollutants, and suggest that substantially increased hepatic lipid deposition may have potentially dangerous toxicological implications for these animals.