The Effects of Resveratrol and Commercial Serum-Free Media on Ovine Oocyte Quality and Cloned Embryo Development

Oocyte in vitro maturation (IVM) and in vitro culture (IVC) allows for rescuing immature oocytes to be used for production of embryos in laboratories. However, IVM currently lags in comparison to naturally occurring maturation regarding post-maturation developmental competency. A downside to relying on IVM is the inclusion of animal serum, which introduces confounding variables and may contribute to growth abnormalities. Commercial IVM media omitting serum are available from various sources including the BO-IVM/IVC culture system from IVF Bioscience. Additionally, the effects of resveratrol supplementation in IVM on sheep oocyte condition are of interest due to observed improvements in matured oocyte quality or embryonic development of sheep, goats, and cattle. Aims. This two-part study aimed to investigate both the effect of BO-IVM/IVC use on oocyte quality, embryonic development, pregnancy, and full-term development, as well as the effect of resveratrol supplementation in IVM media on oocyte quality and embryonic development. Key Results. Resveratrol supplementation (1μM) in IVM demonstrated a reduction in Reactive Oxygen Species (ROS) levels in oocytes when compared to the controls (P < 0.01). The incorporation of BO-IVM/IVC compared to MM/SOF increased both the number of cells within the inner cell mass (ICM) (P < 0.05) and total cell numbers (P < 0.05) of resulting parthenogenetic blastocysts compared to traditional culture conditions. Using BO-IVM/IVC increased the rate at which embryos surpass the 8-cell stage within 48 hours post activation (P < 0.01). Using BO-IVM/IVC decreased expression of genes relating to metabolic regulation and potential for cellular differentiation in cloned embryos (P < 0.01). Use of BO-IVM/IVC improved the 90-day pregnancy rate (P < 0.01), and full-term development rate (P < 0.01). Using BO-IVM/IVC did not significantly affect the Large Offspring Syndrome (LOS) rate in offspring observed at term. Overall, using BO-IVM/IVC significantly improved the cloning efficiency when compared to MM/SOF (P < 0.01). Conclusion. Using BO-IVM/IVC improves embryo development, leading to improvements in cloned offspring gestation, development to term, and cloning efficiency compared to traditional culture conditions, whereas resveratrol supplementation in IVM improves oocyte quality.