Equine Oocyte and Embryo Metabolism in the ART Setting: Current Knowledge and Clinical Significance

• As I understand it there are no highlights needed for a review article given there is no new data presented? I am happy to provide if this is not the case Equine in vitro embryo production has become very efficient and is used extensively worldwide for the clinical production of foals. What we know so far about offspring health and performance is promising; however, elements of the in vitro process remain unphysiological when compared to in vivo conditions. Studying the metabolism of oocytes and embryos can help inform the optimisation of culture systems and identify aberrations if they occur. Given the growing body of knowledge on the downstream effects of an inadequate peri-conception environment, both in vivo and in vitro , it is imperative that fundamental research continues to optimise the culture systems we use. This review describes existing knowledge of the in vivo environment in the context of carbohydrate nutrient provision in addition to glucose and oxidative metabolism of the oocyte and early embryo. Areas are highlighted where further research is required.