Amino Acids of Seminal Plasma Associated With Freezability of Bull Sperm

Abstract

Sperm cryopreservation is an important technique for fertility management, but postthaw viability of sperm differs among breeding bulls. With metabolites being the end products of various metabolic pathways, the contributions of seminal plasma metabolites to sperm cryopreservation are still unknown. These gaps in the knowledge base are concerning because they prevent advances in the fundamental science of cryobiology and improvement of bull fertility. The objective of this study was to test the hypothesis that seminal plasma amino acids are associated with freezability of bull sperm. To accomplish this objective, amino acid concentrations in seminal plasma from seven bulls of good freezability (GF) and six bulls of poor freezability (PF) were quantified using gas chromatography-mass spectrometry (GC-MS). Multivariate and univariate analyses were performed to identify potential freezability biomarkers. Pathways and networks analyses of identified amino acids were performed using bioinformatic tools. By analyzing and interpreting the results we demonstrated that glutamic acid was the most abundant amino acid in bull seminal plasma with average concentration of 3,366 ± 547.3 nM, which accounts for about 53% of total amino acids. The other most predominant amino acids were alanine, glycine, and aspartic acid with the mean concentrations of 1,053 ± 187.9, 429.8 ± 57.94, and 427 ± 101.3 nM. Pearson's correlation analysis suggested that phenylalanine concentration was significantly associated with post-thaw viability (r = 0.57, P-value = 0.043). Significant correlations were also found among other amino acids. In addition, partial least squares-discriminant analysis (PLS-DA) bi-plot indicated a distinct separation between GF and PF groups. Phenylalanine had the highest VIP score and was more abundant in the GF groups than in the PF groups. Moreover, pathway and network analysis indicated that phenylalanine contributes to oxidoreductase and antioxidant reactions. Although univariate analysis did not yield significant differences in amino acid concentration between the two groups, these findings are significant that they indicate the potentially important roles of amino acids in seminal plasma, thereby building a foundation for the fundamental science of cryobiology and reproductive biotechnology.

The Epigenetics of Gametes and Early Embryos and Potential Long-Range Consequences in Livestock Species—Filling in the Picture With Epigenomic Analyses

“…The current knowledge in humans about the different epigenetic signals in sperm that are responsive to environment and evidence of sperm-borne epigenetic factors is well-reviewed in Donkin and Barres ( 2018 ). In cattle, studies using sperm samples from low and high fertility bulls have suggested various sperm factors associated with bull fertility, including sperm proteomics, gene expression, sperm protamine status, macromolecules, metabolomics, superoxide dismutase, and amino acids of seminal plasma (Peddinti et al, 2008 ; Feugang et al, 2010 ; Govindaraju et al, 2012a ; De Oliveira et al, 2013 ; Dogan et al, 2015 ; Grant et al, 2015 ; Kaya and Memili, 2016 ; Kutchy et al, 2017 , 2019 ; Velho et al, 2018 , 2019 ; Viana et al, 2018 ; Menezes et al, 2019 ; Ugur et al, 2019 ; Memili et al, 2020 ).…”

Lipidomic markers of sperm cryotolerance in cattle

“…Sperm freezability was determined according to methods that have been previously described by other researchers 12 . Briefly, bulls (Alta Genetics, Watertown, WI, USA) were selected based on post-thaw viability data that were collected from 2008 to 2016.…”

The characteristics of proteome and metabolome associated with contrasting sperm motility in goat seminal plasma

“…In seminal plasma, the components generally consist of proteins, ions, and metabolites like nucleosides, lipids, monosaccharides, amino acids, minerals, electrolytes, and also steroid hormones 9,10 . Previous studies have proved that seminal plasma contributes a signi cant role in regulation of sperm motility and fertilization [11][12][13][14][15] . Seminal plasma provides metabolic support, and it has a complicated and not well-understood effect on the physiological role of sperm.…”