Anethole addition during in vitro follicle culture and oocyte in vitro maturation improves cumulus-oocyte complexes quality and embryo production rates.

In vitro follicle culture (IVFC) supports the development of in vitro-grown cumulus-oocyte complexes (COCs), but oocyte maturation and embryo production rates from these COCs are often lower than those of in vivo-derived counterparts. Anethole, a natural antioxidant, has shown potential to improve follicle development and oocyte maturation in vitro. However, the optimal timing of anethole supplementation during IVFC and/or in vitro maturation (IVM), and its impact on developmental outcomes relative to in vivo-derived COCs, remains to be clarified. This study aimed to investigate whether the addition of anethole during IVFC and/or IVM enhances the quality of in vitro-grown COCs and yields embryo production outcomes comparable to those obtained from in vivo-derived COCs in goats. Early antral follicles were cultured in IVFC medium with 300 μg/mL anethole or without it for 18 days, followed by IVM of in vitro-grown COCs in the absence or presence of 30 μg/mL anethole. This resulted in four treatments: IVFC/IVM (-AN/-AN, -AN/+AN, +AN/-AN, +AN/+AN). The addition of anethole during IVFC improved meiotic resumption and oocyte viability regardless of its presence during IVM. Metaphase II rate increased only when anethole was added during both IVFC and IVM. Cumulus cell viability was higher in all anethole-treated groups. Anethole also improved cleavage and blastocyst formation rates of in vitro-grown COCs and enhanced cleavage and embryonic development in in vivo-grown COCs. Notably, embryo development and blastocyst formation were similar between in vitro- and in vivo-derived COCs. In conclusion, anethole supplementation during IVFC and IVM improves oocyte quality and embryo development, achieving outcomes comparable to those obtained from in vivo-grown oocytes.