OBJECTIVES: We tested the toxicity of ethinylestradiol, a semisynthetic estrogen used in oral contraceptives, on all-male triploid zebrafish using commercial feeds and three different doses concentrations. We aimed to determine whether ethinylestradiol peroral administration resulted in vitellogenin production and whether all-male triploid zebrafish could serve as a model species for xenoestrogen testing. METHODS: The actual concentrations of 17α-ethinylestradiol were 0.0035 (low); 0.0315 (medium) and 0.365 (high) μg/g. Positive control represented commercial feeds containing 0.0465 μg/g of β-estradiol. The experiment lasted 8 weeks. RESULTS: Our results indicate that 17α-ethinylestradiol consumption does induce vitellogenin production in triploid zebrafish. CONCLUSIONS: The simple presence of vitellogenin is a definite symptom indicative of the potential for such changes due to the action of estrogenic substances. As such, this experiment has shown that the use of all-male triploid zebrafish populations, rather than the mixed-sex populations of other species previously used, could serve as a suitable alternative model population for controlled testing of the effects of xenoestrogens on fish.

Department of Animal Breeding Animal Nutrition and Biochemistry University of Veterinary Sciences Brno Czech Republic Czech Republic

Department of Animal Protection and Welfare and Veterinary Public Health University of Veterinary Sciences Brno Czech Republic Czech Republic

Department of Pharmaceutical Technology Masaryk University Brno Czech Republic Czech Republic

Department of Zoology Fisheries Hydrobiology and Apiculture Faculty of Agrosciences Mendel University Brno Czech Republic Czech Republic

South Bohemian Research Centre of Aquaculture and Biodiversity of Hydrocenoses Faculty of Fisheries and Protection of Waters University of South Bohemia in Ceske Budejovice Vodnany Czech Republic Czech Republic