Correlation Analysis of Sperm Cryopreservation Quality with Serum Testosterone and Sperm gDNA Methylation Levels in Xiaoshan Chickens

Chicken semen cryopreservation is crucial for utilizing high-quality cockerel genetics, but semen is highly sensitive to cryoinjury, leading to poor preservation outcomes. This study aimed to establish a theoretical foundation for selecting cockerels for semen cryopreservation through serum testing and to improve semen quality via DNA methylation editing. Semen and serum samples were collected from 102 Xiaoshan cockerels, with semen cryopreserved and thawed following standardized protocols. Post-thaw semen quality and serum testosterone (T) levels were assessed. Eight cockerels were selected based on motile sperm quality, and whole-genome bisulfite sequencing (WGBS) was used to analyze sperm DNA methylation. The results showed a significant positive correlation between serum T levels and sperm motility. There were notable differences in sperm motility and serum T levels between high-quality and low-quality semen groups but no differences in estradiol (E₂), superoxide dismutase (SOD), or glutathione peroxidase (GSH-Px) levels. A total of 217 differentially methylated regions (DMRs) and 116 differentially methylated genes (DMGs) were identified. Key genes such as <i>PRKACB</i> (protein kinase, cAMP-dependent, catalytic, beta) and <i>ACSL1</i> (long-chain-fatty-acid--CoA ligase 1) were associated with sperm motility. These findings provide important insights for improving semen cryopreservation and contribute to breeding practices and the development of cryoprotectants.