Biostimulation with rams improved embryo quality without modifying the ovulatory response in superovulated ewes

The aim of this study was to evaluate whether extended ram exposure during FSH superovulatory treatment improves follicular growth, embryo production, and embryo quality in ewes. Twenty Santa Inês ewes were subjected to a superovulation protocol based on follicle-stimulating hormone (FSH) administration with or without male biostimulation in a crossover arrangement (n = 20 per treatment). Follicular development and corpus luteum functionality were monitored with ultrasound, and embryo collection was performed non-surgically. Recovered embryos were analyzed for gene expression, reactive oxygen species (ROS) levels, and blastomere count. Male biostimulation for 72 h did not modify the number or diameter of antral follicles, the recovery rate of structures, reactive oxygen species (ROS) levels, and blastomere count. However, it reduced the expression of genes linked to oxidative stress (PRDX1) and apoptosis (BCL2) in embryos. In summary, exposure to rams for 72 h during superovulatory treatment influenced molecular indicators of development competence, specifically the relative abundance of BCL2 and PRDX1 transcripts, which are associated with cellular apoptosis and stress. However, it did not improve the ovarian responses.