Seminal Plasma Metabolomic Responses to Selenium Supplementation and Testicular Heat Stress in Zulu Rams

Selenium plays an essential role in animals because of its antioxidant properties and direct influence on reproductive health, which improves sperm quality for maximum fertility. This study aimed to investigate the untargeted metabolomic profiling of seminal plasma of Zulu rams exposed to heat stress and selenium supplementation. For this, seminal plasma (SP) was harvested from semen (stored at −80 °C) collected from 20 Zulu rams aged 2–5 years that were randomized into four groups according to their body weight and scrotal circumference: selenium with testicular heat stress; G1, selenium; G2, control; G3, and 6 weeks of exposure to testicular heat stress; G4. Untargeted spectrum data were analyzed using MetaboAnalyst, and normalized to ensure reproducibility and reliability, and quality control samples were generated by mixing small aliquots of each analytical sample to assess metabolite variance. The study identified a total of 536 metabolites potentially linked to fertility, over 50% of which were unclassified. Of the 536 metabolites, 359 were conserved across all treatment groups. Selenium supplementation resulted in a reduction in the abundance of several metabolites involved in pathways of pyrimidine metabolism, fatty acid biosynthesis, glycine/serine/threonine metabolism, and aminoacyl-tRNA biosynthesis. The supplementation of selenium for rams under heat stress conditions altered pathways related to branched-chain amino acid metabolism, alanine/aspartate metabolism, and glutathione metabolism. Conversely, heat stress conditions without selenium supplementation reduced pathways associated with caffeine metabolism, fatty acid degradation, pyrimidine metabolism and flavonoid biosynthesis. The study was able to reveal seminal plasma metabolites induced by selenium supplementation and heat stress conditions. However, the study faced a major limitation of a high proportion of uncharacterized metabolites.