Bisphenol A and S affect early embryonic development in cattle

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The cattle industry contributes billions of dollars and thousands of jobs annually to the Canadian economy. A key to its success is the efficient production of healthy bovine embryos. Although the advance in reproductive biotechnologies is striking, the overall fertility of cattle is as low as 35% with the majority of embryo loss during the first weeks of development. Understanding factors that affect bovine embryo development offers a model to study mechanistic pathways that can be translated in other mammals, while improving cattle fertility. *** My primary research program combines the basic understanding of embryo development to the focus on the effects of environmental stressors, especially Endocrine Disrupting Compounds (EDCs), on early embryonic loss, with the long-term goal of limiting embryo loss during the first week of development, therefore increasing the chances of producing healthy bovine embryos and improving reproductive biotechnologies in farm animals. This project focuses on the effect of specific EDCs, with the short-term goals of investigating the effects and mechanism of action of Bisphenol A (BPA) and Bisphenol S (BPS), on bovine early embryo development.***EDCs are environmental stressors with estrogen-like potential that impact fertility, with BPA being one of the highest volume chemicals produced worldwide. We have shown that bovine oocytes exposure to BPA resulted in spindle abnormalities, reduced meiosis progression, decreased blastocyst development, increased apoptosis and changes in genes and proteins. Concerns over BPA effects led to the use of its analog BPS, that however also has negative effects on oocyte maturation.***Both BPA and BPS induce spindle abnormalities and chromosome misalignment in bovine at concentrations significantly lower than the ones observed in humans, suggesting the bovine reproductive system is even more susceptible to bisphenols. These data support our rationale that bisphenols, especially BPA, affect cattle reproductive capability. *** Therefore, we hypothesize that BPA and BPS contribute to the decrease in cattle reproductive efficiency.***Objective 1: Investigate BPA and BPS mechanisms of action during oocyte maturation and early embryo development***Objective 2: Investigate the role of BPA and BPS in inducing early embryonic arrest. ***Objective 3: Study the epigenetic changes caused by BPA and BPS during in vitro development. ***Objective 4: Identify the changes in the metabolomics profile due to BPA and BPS exposure during in vitro development. ***A better understanding of the link between EDCs exposure and reproductive decline in cattle is of growing scientific and economic importance. Our research program 1) can substantially contribute to assess whether BPS is a valid substitute for BPA and 2) can drive to implement changes in farm animal environment/feeding system to limit the exposure to bisphenols, and EDCs in general, to reduce their potential effects on cattle reproductive capability.**