The preservation of semen is pivotal in animal reproduction to ensure successful fertilization and genetic improvement of livestock and poultry. However, investigating the underlying causes of differences in sperm liquid preservation ability and identifying relevant biomarkers remains a challenge. This study utilized liquid chromatography-mass spectrometry (LC-MS) to analyze the metabolite composition of seminal plasma (SP) from two groups with extreme differences in sperm liquid preservation ability. The two groups namely the good liquid preservation ability (GPA) and the poor preservation ability (PPA). The aim was to explore the relationship between metabolite composition in SP and sperm liquid preservation ability, and to identify candidate biomarkers associated with this ability of sperm. The results revealed the identification of 756 metabolites and 70 differentially expressed metabolites (DEM) in the SP from two groups of boar semen with differing liquid preservation abilities at 17 °C. The majority of identified metabolites in the SP belonged to organic acids and derivatives as well as lipids and lipid-like molecules. The DEM in the SP primarily consisted of amino acids, peptides, and analogs. The Kyoto Encyclopedia of Genes and Genomes analysis also demonstrated that the DEM are mainly concentrated in amino acid synthesis and metabolism-related pathways (P < 0.05). Furthermore, eleven key metabolites were identified and six target amino acids were verified, and the results were consistent with the non-targeted metabolic analysis. These findings indicated that amino acids and their associated pathways play a potential role in determining boar sperm quality and liquid preservation ability. D-proline, arginine, L-citrulline, phenylalanine, leucine, DL-proline, DL-serine, and indole may serve as potential biomarkers for early assessment of boar sperm liquid preservation ability. The findings of this study are helpful in understanding the causes and mechanisms of differences in the liquid preservation ability of boar sperm, and provide valuable insights for improving semen quality assessment methods and developing novel extenders or protocols.
Keywords: amino acid; boar; liquid preservation ability; metabolome; seminal plasma; sperm.
The current main method for preserving boar semen used in artificial insemination is liquid preservation. However, the preservation ability of boar sperm has large individual differences, and understanding the factors that influence this ability of sperm and identifying relevant biomarkers present challenges. Given the crucial role of seminal plasma (SP) in sperm survival and functionality maintenance, this study utilized liquid chromatography-mass spectrometry to analyze the metabolite composition of the SP from two groups with extreme differences in sperm liquid preservation ability. The aim was to explore the relationship between metabolites in SP and sperm liquid preservation ability, and identify candidate biomarkers associated with this ability of sperm. The results revealed the important role of amino acids and related pathways in determining boar sperm quality and storage ability. Several potential biomarkers for early evaluation of boar sperm liquid preservation ability, including D-proline, arginine, L-citrulline, phenylalanine, leucine, DL-proline, DL-serine, and indole were identified. This study provides valuable insights into the reasons and mechanisms behind differences in sperm liquid preservation ability and offers possibilities for improving semen preservation techniques.
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