Integrated proteomic and metabolomic analyses reveal testicular metabolic mechanisms underlying sperm quality in drakes.

This study aimed to analyze the testicular metabolic mechanisms associated with the sperm quality of drakes from proteomic and metabolomic perspectives. Testicular tissues were collected from 12 drakes (six with significantly high and six with significantly low sperm quality) to evaluate sperm quality parameters. Ultra-deep quantitative proteomics and ultra-performance liquid chromatography-tandem mass spectrometry were employed to analyze differences in testicular proteomics and metabolites between groups. Enrichment analysis of differentially expressed proteins (DEPs) and metabolites (DEMPs) in testicular tissues was performed to identify key pathways associated with sperm quality. In total, 153 DEPs (65 upregulated, 88 downregulated) and 98 DEMPs (15 upregulated, 83 downregulated) were identified in the testes of drakes with varying sperm quality. Functional enrichment analysis revealed that these DEPs and DEMPs were mainly involved in the key biological processes and pathways of oxidative phosphorylation, fatty acid degradation, glycerophospholipid metabolism, and purine metabolism. Notably, downregulated carnitines highlighted lipid metabolic balance and fatty acid-derived energy as critical for sperm motility, while differential expression of oxidative phosphorylation core proteins (e.g., ATP6V0C, SDHD) confirmed efficient ATP production as pivotal for sperm function. Purine metabolism and related metabolites further linked metabolic homeostasis to potential energy dysfunction or DNA damage. These findings fill gaps in avian sperm research and identify candidate targets (proteins, metabolites, and pathways) for genetic breeding to enhance avian male fertility and optimize poultry breeding programs.