Aflatoxin M1 effects on Xenopus Laevis Development

BACKGROUND: The principal Aflatoxin B1 (AFB1) hydroxylated metabolite excreted in milk is Aflatoxin M1 (AFM1) classified in group 2B by the International Agency for Research on Cancer (IARC). Human exposure to AFM1 is due to the consumption of contaminated dairy products and partly to endogenous production through AFB1 liver metabolism. METHODS: Since no data are available on AFM1 embryotoxicity, its lethal and teratogenic potential was investigated using the Frog Embryo Teratogenesis Assay–Xenopus (FETAX). Stage-8 blastulae were exposed to AFM1 at 1, 4, 16, 64, and 256 mg/L concentrations until stage 47, free-swimming larva. RESULTS: A slight increase of mortality and malformed larva percents was found in AFM1-exposed groups but these differences were not statistically significant in comparison with the controls. CONCLUSIONS: Therefore, AFM1 is a non-embryotoxic compound when evaluated with a FETAX model at concentrations under the conditions tested. However, AFM1 merits further studies using mammals as experimental models to identify a possible risk during human pregnancy. Brith Defects Research (Part B) 77:234–237, 2006.