Association between sperm progressive motility and seminal fluid metabolomic and lipidomic profiling of bovine...

Progressive motility refers to sperm's forward movement, which is essential for male reproductive performance. The mechanism underlying the acquisition and maintenance of progressive motility is not yet clear. Thus, our aim was to examine the association between progressive motility and the metabolomic and lipidomic profiles of bovine the seminal fluid. Fresh ejaculates from 12 bulls were classified by computer-assisted sperm analysis as high (>74%), medium (60-74%), or low (<60%) progressive motility (HPM, MPM, and LPM, respectively). Then, seminal fluid was separated from the ejaculate and subjected to metabolomics (n = 4 samples per group) and lipidomic (n = 3 samples per group) analysis. Findings revealed differential contents of 58 metabolites, in particular between the HPM vs. LPM and between MPM vs. LPM seminal fluids. KEGG annotation identified several metabolic pathways potentially associated with progressive motility phenotypes, including arginine biosynthesis, arginine and proline metabolism, riboflavin metabolism, taurine and hypotaurine metabolismand beta-alanine metabolism. As a proof of concept, an in-vitro experiment was conducted with riboflavin; sperm incubation with 0.1, 1 or 10 µM riboflavin for 1 h enhanced the progressive motility of LPM sperm to some extent. Lipidomic analysis of the seminal fluid revealed 39 lipid species that differed between groups, with a main difference between HPM and MPM groups. In addition, glycerophosphocholines and phosphatidylcholines lipids were differentially expressed across HPM vs. LPM and HPM vs. MPM comparisons. The findings suggest an association between sperm progressive motility and the seminal fluid extracellular metabolites; these metabolites might serve as biomarkers for ejaculate quality.