Multi-omics analyses reveal steroid hormone and antioxidant pathways regulating sperm storage capacity in female...

The duration of fertility in poultry is directly influenced by sperm store ability within specialized sperm storage tubules (SSTs) of the female uterovaginal junction (UVJ). Improving the duration of fertility reduces artificial insemination frequency, influencing animal welfare, and production costs. Here, we investigated physiological and multi-omic factors underlying sperm storage capacity in female Muscovy ducks (Cairina moschata). Phenotypes were collected from approximately 1,500 ducks for three generations, with focus on the peak and late laying stages. High and low sperm storage individuals were classified for histological evaluation and multi-omics analyses (transcriptomics, proteomics, and metabolomics). Results show sperm storage capacity significantly declines with age, associated with ciliated cell integrity in the UVJ microenvironment. Multi-omics revealed enrichment in pathways, including steroid hormone biosynthesis, glutathione metabolism, and tryptophan metabolism. Metabolites such as cholesterol and progesterone were identified as potential biomarkers. Down-regulation of LIMA1 and CYP2R1, along with altered functional pathways, suggests coordinated regulation of antioxidation balance, immune response, and steroid synthesis within the UVJ microenvironment. Our findings provide a multi-omics framework for better understanding fertility duration and offer biomarker candidates and pathways for future genetic improvement in poultry reproduction.