Effects of exposure to food contaminated with PBDE, PCN or PCB on reproduction, liver morphology and cytochrome P450 activity in the three-spined stickleback, Gasterosteus aculeatus

Abstract

Female three-spined sticklebacks were fed with freeze-dried chironomids contaminated with low or high doses of polybrominated diphenyl ethers (PBDEs) (Bromkal 70-5DE), polychlorinated naphthalenes (PCNs) (Halowax 1014) and polychlorinated biphenyls (PCBs) (Clophen A50). After 3.5 months of exposure, reproduction studies were started. No significant difference in number of eggs laid was found between the control and exposed groups. Spawning success (considered successful if it occurred within 24 h) in the control group was 80%, whereas it was 20% and 25% in the groups that received high doses of Bromkal 70-5DE or Clophen A50, respectively. After spawning, the fish were dissected for chemical, biochemical and morphological analyses. Levels of PBDE in the low- and high-dose Bromkal 70-5DE groups were 861 ± 271 and 1630 ± 275 mg/kg fat, respectively, whereas the corresponding concentrations of PCN in the Halowax 1014 groups were 845 ± 43 and 1929 ± 72 mg/kg fat, respectively. Concentrations of PCB in fish from the Clophen A50 groups were 1972 ± 158 and 3594 ± 521 mg/kg fat, respectively. Uptake efficiency was approx. 40% for PCB and 20% for PBDE and PCN. Hepatic cytochrome P450-dependent ethoxyresorufin- O-deethylase (EROD) activity was induced by Clophen A50 and Halowax 1014, whereas Bromkal 70-5DE did not significantly induce the enzyme system. EROD activity was 0.8 pmol/mg prot./min in the control group, whereas it was between 2.7 and 16.3 pmol/mg prot./min in the exposed groups. Furthermore, the morphological examination of the liver disclosed pronounced lipid accumulation in all exposed groups.