Advances in porcine stem cell research and their applications in agriculture.

Porcine stem cell research has advanced considerably over the past decade, driven by the dual promise of biomedical modeling and agricultural innovation. This review provides a comprehensive synthesis of recent progress in the isolation, characterization, and directed differentiation of major porcine stem cell types, including embryonic stem cells (pESCs), induced pluripotent stem cells (piPSCs), germline stem cells (pGSCs, spermatogonial stem cells and the controversially debated female germline stem cells), and various adult stem cell populations (e.g., muscle satellite cells, adipose-derived stem cells). We critically analyze persistent challenges that hinder translational applications. For pESCs and piPSCs, achieving stable, germline-competent pluripotency remains challenging. This difficulty arises from species-specific epigenetic roadblocks, such as aberrant DNA methylation and incomplete X-chromosome reactivation, as well as suboptimal culture conditions. For pGSCs, the lack of validated molecular markers for spermatogonial stem cells persists, and the existence of female germline stem cells in postnatal ovaries remains scientifically debated. Focusing on agricultural translation, we examine two key application domains. First, in cultured meat production, porcine muscle and adipose stem cells (or pluripotent stem cell-derived progenitors) are cultivated in vitro to generate muscle and fat tissues. While this approach offers a promising complement to conventional livestock farming, major hurdles remain, including loss of stemness during large-scale expansion, the high cost of serum-free media, the need for edible scaffolds that replicate meat texture, and regulatory approval pathways. Second, in stem cell-based genetic breeding, concepts such as in vitro breeding (combining genomic selection with in vitro gametogenesis) could dramatically accelerate genetic gain. However, realization requires robust, species-optimized protocols for complete in vitro gametogenesis in pigs, which have not yet been achieved. Finally, we integrate ethical and regulatory considerations, emphasizing that proactive frameworks must evolve in parallel with scientific advances to ensure responsible innovation. By highlighting both the transformative potential and the remaining technical, biological, and regulatory barriers, this review aims to guide future research toward sustainable, efficient, and welfare-conscious swine agriculture.