Sperm physiology and in vitro fertilising ability rely on basal metabolic activity: insights from the pig model

Metabolic activity of mammalian sperm is shown to influence reproductive outcomes beyond fertilisation. Whether basal metabolic activity in sperm has any influence on their fertilising capacity has not been explored. Using the pig as a model, the present study investigated the relationship of energetic metabolism with sperm quality and function (assessed through computer-assisted sperm analysis and flow cytometry), and fertility (in vitro fertilisation (IVF) outcomes). In semen samples from 16 boars, levels of metabolites related to glycolysis, ketogenesis and Krebs cycle were determined through a targeted metabolomics approach using liquid chromatography-tandem mass spectrometry. High-quality sperm are associated to greater levels of glycolysis-derived metabolites, and oocyte fertilisation and embryo development are conditioned by the sperm metabolic status. Interestingly, glycolysis appears to be the preferred catabolic pathway of the sperm giving rise to greater percentages of embryos at day 6. In conclusion, this study shows that the basal metabolic activity of sperm influences their function, even beyond fertilisation.

Automated summary

Using pig as a model, this study investigated the relationship between metabolic activity of sperm and their quality, function, and fertility outcomes. High-quality sperm were associated with higher levels of glycolysis-derived metabolites, and the metabolic status of sperm greatly influenced oocyte fertilisation and embryo development. Overall, this study demonstrates that the basal metabolic activity of sperm influences their function, extending beyond fertilisation.