Proteomic profiling of pig placenta reveals key biomarkers linked to sow reproductive performance

Reproductive performance is a key factor in swine farming, yet the molecular mechanisms underlying critical reproductive traits remain poorly understood. This study utilized mass spectrometry-based proteomics to analyze protein expression profiles in pig placenta, categorizing samples by sow age, parity, and stillbirth incidence. A total of 8261 proteins were identified, with gene ontology analysis highlighting roles in proteolysis, transcriptional regulation, and immune response. Comparative analysis revealed 87 differentially expressed proteins (DEPs) between young and old sows, 115 DEPs between low and high parity sows, and 103 DEPs linked to stillbirth incidence. Notable proteins, such as laminin G2, methionine sulfoxide reductase B3, and FERM domain-containing 7, were significantly correlated with reproductive traits. Integrative analysis identified YEATS domain-containing 4 as a consistently downregulated protein across all traits, while nephrocystin 1 was linked to low birth weight and stillbirth incidence. Functional enrichment analysis underscored the role of cytoskeletal proteins and transporters in placental nutrient exchange and fetal development. This study expands the understanding of pig placental proteomics and identifies potential biomarkers for improving sow reproductive performance. Future studies will focus on validating these findings and translating them into practical applications for breeding selection and reproductive management in swine production. • Identified 8261 placental proteins, expanding the pig reproductive proteome. • Found 87 age-, 115 parity-, and 103 stillbirth-related differentially expressed proteins. • Laminin G2 and MSRB3 linked to placental function and fetal development. • YEATS4 downregulated across traits; nephrocystin 1 linked to stillbirth and low birth weight. • Cytoskeletal proteins and transporters are key to placental nutrient exchange.