Beta-naphthoflavone liver EROD and erythrocytic nuclear abnormality induction in juvenile Dicentrarchus labrax L

Juvenile Dicentrarchus labrax L. (sea bass) was exposed to five different beta-naphthoflavone (BNF) concentrations-0, 0.1, 0.3, 0.9 and 2.7 microM-for 0, 2, 4, 6, 8, 16, 24, 48, 72, 144, and 216 h. A battery of biomarkers was investigated, such as liver ethoxyresorufin-O-deethylase (EROD), liver cytochrome P450 (P450 content), liver aminotransferase (ALT activity), liver somatic index (LSI), micronuclei (MN), and erythrocytic nuclear abnormality (ENA) frequencies. Juvenile D. labrax L. liver EROD induction started at 2 h exposure to 2.7 microM BNF and 6 h exposure to 0.1, 0.3, and 0.9 microM BNF, respectively. A significant liver EROD decrease was observed between 8 and 16 h for all BNF concentrations, followed by a slight increase after 48 h exposure to 0.9 and 2.7 microM BNF and a definitive decrease from 72 h exposure onward. Liver P450 content significantly increased at 2, 6, and 8 h exposure, respectively, to 2.7 microM, 0.9, 0.3, and 0.1 microM BNF. However, liver P450 content remained significantly higher than that of the control from 72 to 216 h in the sea bass exposed to 2.7 microM BNF. Sea bass ENA induction started at 4h exposure to 0.9 and 2.7 microM BNF, and significantly increased to 16 and 24 h exposure, whereas for 0.3 microM BNF a significant increase started after 8 h exposure. A significant ENA frequency increase was still observed at 144 and 216 h exposure to 0.9 and 2.7 microM BNF. The micronuclei induction was observed at 4, 6, and 8 h, respectively, after 2.7, 0.9, and 0.3 microM BNF exposure. However, there was a micronuclei frequency decrease for 0.3, 0.9, and 2.7 microM BNF exposure concentrations between 8 and 16 h, followed by a slight increase after 48, 72, and 144 h exposure, respectively, to 2.7, 0.9, and 0.3 microM BNF. Liver somatic index significantly increased after 216 h, whereas ALT activity significantly decreased at 144 and 216 h 2.7 microM BNF exposure.