Proteomic analysis reveals **468 differentially expressed proteins** in Jining Grey Goat ovaries linked to litter size

Optimizing goat reproductive performance, particularly litter size, is crucial for livestock productivity. The ovary is central to this process, yet the precise molecular mechanisms linking ovarian protein dynamics to prolificacy remain largely unknown. Current breeding strategies often lack a deep understanding of these underlying proteomic changes. This study aims to bridge this gap by investigating the ovarian proteome of the highly prolific Jining Grey Goat, providing insights into the genetic basis of fertility traits.

Researchers selected 8 Jining Grey Goats, dividing them into a single-birth group (n=4) and a multiple-birth group (n=4). Ovarian tissue samples were collected from both groups. Protein expression differences were investigated using iTRAQ technology for quantitative proteomic analysis, followed by bioinformatics analysis to identify enriched pathways and protein interaction networks. Key candidate proteins were then validated via Western blot to confirm expression trends, comparing protein levels between the two litter size groups.

Quantitative proteomic analysis identified a total of 468 differentially expressed proteins (DEPs) in the ovaries of Jining Grey Goats with varying litter sizes. Of these, 255 proteins were significantly up-regulated, while 213 were down-regulated in the multiple-birth group compared to the single-birth group.

Gene Ontology (GO) enrichment analysis revealed these DEPs were primarily involved in crucial biological processes such as cellular and metabolic processes, alongside molecular functions like actin filament binding and calcium ion binding. KEGG pathway enrichment analysis highlighted significant enrichment in pathways including focal adhesion, the Oxytocin Signaling Pathway, and the PPAR Signaling Pathway. Protein interaction network analysis pinpointed CAV1, FLNA, CNN1, TAGLN, and MYH11 as key candidate proteins influencing prolific traits. Subsequent Western blot verification confirmed expression trends consistent with the iTRAQ results for these identified proteins.