Comparative Transcriptomic Analysis of In Vitro Matured Oocytes From Cyclic and Prepubertal Gilts Reveals Distinct Molecular Patterns.

In vitro embryo production is a key tool in reproductive biotechnology, enabling genetic improvement, basic research on early development, and the generation of biomedical models. Despite high rates of nuclear maturation achieved during in vitro maturation (IVM) of porcine oocytes, inadequate cytoplasmic maturation continues to limit oocyte competence and subsequent development, particularly when using oocytes from prepubertal gilts (PG). The molecular basis underlying differences in oocytes from cyclic females remains incompletely understood. In this study, we performed a comparative transcriptomic analysis of immature (IMO) and in vitro matured oocytes (MO) from cyclic (CG) and PG using RNA sequencing (n = 20/group in 6 replicates). Differential expression analyses (FDR < 0.05) revealed extensive transcriptional changes between groups. The CG group showed enrichment of genes related to MAPK and PI3K-Akt signalling, and extracellular matrix interactions in MO vs. IMO, consistent with a more coordinated and developmentally competent maturation program. In contrast, oocytes from the PG group were enriched in genes related to cell cycle regulation, DNA damage response and homologous recombination, indicating a likely impairment in cytoplasmic maturation. Overall, our results provide complementary insight into the differences in the biological processes underlying IVM of oocytes retrieved from PG or CG in the porcine species.