BISPHENOL S ALTERS EMBRYONIC VIABILITY, DEVELOPMENT, GALLBLADDER SIZE, AND MESSENGER RNA EXPRESSION IN CHICKEN EMBRYOS EXPOSED VIA EGG INJECTION

Amid concerns about the toxicological effects and environmental prevalence of bisphenolA(BPA), efforts to find suitable, safer replacement alternatives are essential. Bisphenol S (BPS) is a potential chemical substitute for BPA; however, few studies are available confirming that it has a more desirable ecotoxicological profile. In the present study, BPS was injected into the air cell of unincubated, fertilized chicken embryos at 6 concentrations ranging from 0 mu g/g to 207 mu g/g egg to determine effects on pipping success, development, hepaticmessenger ribonucleic acid(mRNA) expression, thyroid hormone levels, and circulating bile acid concentrations. Concentrations of BPS increased in a dose-dependent manner in whole-embryo homogenates, and exposure to the highest dose, 207 mu g/g, resulted in decreased pipping success (estimated median lethal dose = 279 mu g/g; 95% confidence interval = 161-486 mu g/g). Exposure to BPS also reduced growth metrics including embryo mass and tarsus length, whereas the most pronounced phenotypic effect was the concentration-dependent, significant increase in gallbladder size at concentrations = 52.8 mu g/g. These adverse phenotypic outcomes were associated with the modulation of gene targets from a chicken ToxChip polymerase chain reaction array, which are involved with xenobiotic metabolism, lipid homeostasis, bile acid synthesis, and the thyroid hormone pathway. Expression levels of 2 estrogen-responsive genes, apolipoprotein II and vitellogenin, were too low at the sampling time point assessed (i.e., pipping embryos) to quantify changes, and no effects were observed on circulating free thyroxine or bile acid concentrations. The present study provides novel, whole-animal toxicological data for a BPA replacement alternative that is not well characterized. (C) 2015 SETAC