Metabolomic Analysis of Cauda Epididymal Fluid in Yaks and Cattle

ABSTRACT:

The epididymis is the primary organ responsible for sperm maturation, with its caudal region serving as the primary storage site for mature sperm. The unique small molecule metabolites present in the cauda epididymal fluid not only facilitate the long-term storage of sperm but also ensure their structural and functional integrity prior to fertilization. Consequently, an in-depth investigation into the composition and functions of these metabolites in the cauda epididymal fluid is essential for elucidating the regulatory mechanisms governing sperm maturation and fertilization. Yaks, as livestock unique to the Qinghai-Tibet Plateau, hold significant scientific and economic value. Compared to cattle, male yaks exhibit poorer reproductive performance, characterized by ​reduced sperm motility, elevated sperm abnormality rate, and ​lower artificial insemination conception rates. To investigate the relationship between sperm motility defects in yaks and the microenvironment during their maturation, this study collected cauda epididymal fluid from yaks and cattle for untargeted metabolomic sequencing. The results indicated that 1,098 and 1,297 kinds of metabolites annotated by the Human Metabolome Database (HMDB) database were identified in yak and cattle cauda epididymal fluid, respectively, using positive and negative ion modes. In both modes, the three categories containing the most types of metabolites were organic acids and derivatives, organoheterocyclic compounds, and lipids and lipid-like molecules. Within the lipid metabolites, fatty acids and conjugates were the most prevalent in both modes. In the positive ion mode, compared to cattle cauda epididymal fluid, 79 metabolites were significantly upregulated and 212 were significantly downregulated in yak cauda epididymal fluid. In the negative ion mode, compared to cattle cauda epididymal fluid, 110 metabolites were significantly upregulated and 230 metabolites were significantly downregulated in yak cauda epididymal fluid. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment results showed that the most significantly enriched pathway in the positive ion mode was the biosynthesis of amino acids, while in the negative ion mode, it was ABC transporters. Among the significant differentially expressed metabolites, 18 have been associated with sperm mobility, maturation or function. The functions of these metabolites involve regulation of oxidative stress, sperm capacitation, spontaneous acrosome reaction, mitochondrial energy metabolism, mRNA methylation, and flagellar motility. Taken together, these findings establish a foundational dataset and offer novel perspectives for elucidating the molecular mechanisms underlying yak sperm maturation, enhancing sperm motility, optimizing reproductive techniques, and ultimately improving reproductive performance.

INSTRUMENT(S): Liquid Chromatography MS - negative - reverse phase, Liquid Chromatography MS - positive - reverse phase

PROVIDER: MTBLS13067 | MetaboLights | 2025-09-29

REPOSITORIES: MetaboLights