Effects of Dietary Iron Concentrations on the Cytochrome P450 System of Atlantic Salmon (Salmo salar)

Abstract

Groups of Atlantic salmon (Salmo salar) parr were fed a basal diet containing 27 mg Fe∙kg feed−1 supplemented with different iron levels (0, 80, and 160 mg∙kg−1, respectively) for 8 wk. After this period, a subgroup of each iron regime was treated intraperitoneally with β-naphthoflavone (BNF), a potent inducer of cytochrome P450 1A1 in fish. Differences between the iron regimes were observed in hepatic iron content, which was higher in the high-iron group, and in P450 1A1 levels and monooxygenase activity, measured as 7-ethoxyresorufin O-deethylase (EROD), which were lower in the high-iron group. Differences were also observed in the induction response of P450 1A1 and EROD to BNF. Levels of a constitutive isozyme denoted P450con, belonging to the P450 3A subfamily, did not respond to the dietary iron in the same manner, demonstrating selective regulatory effects of iron on different P450 isozymes.