From Zygote to Blastocyst-Molecular Aspects of Porcine Early Embryonic Development.

Early mammalian embryo development is a temporally regulated process initially governed by maternal factors during the first few cleavage divisions. In porcine embryos, the transition from oocyte to embryonic control occurs around the 4-cell stage. This developmental progression depends on embryonic genome activation (EGA), epigenetic reprogramming, metabolic cues, and extracellular signaling pathways. While fundamental aspects of early development are conserved across mammals, porcine embryos exhibit distinct molecular features, including unique EGA timing, altered regulatory gene expression, and a pronounced reliance on lipid metabolism. This review provides a comprehensive overview of recent advances in understanding the molecular mechanisms underlying early porcine embryo development, from fertilization to blastocyst formation. It summarizes molecular changes associated with the maternal regulation of initial embryonic divisions, genome activation, chromatin remodeling, and the role of transcription factors and metabolic pathways. Additionally, the review examines the impact of in vitro culture conditions on these molecular processes. A thorough understanding of these mechanisms is critical for optimizing embryo culture systems, improving developmental outcomes, and advancing agricultural biotechnology.