Ugur Muhammet Rasit, Dinh Thu, Hitit Mustafa, Kaya Abdullah, Topper Einko, Didion Bradley, Memili Erdogan
Department of Animal and Dairy Sciences, Mississippi State University, Starkville, MS, United States.
Department of Animal Genetics, Kastamonu University, Kastamonu, Turkey.
Front Cell Dev Biol. 2020 Jan 14;7:347. doi: 10.3389/fcell.2019.00347. eCollection 2019.
Sperm cryopreservation is an important technique for fertility management, but post-thaw 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 ( = 0.57, -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.
精子冷冻保存是生育管理的一项重要技术，但解冻后精子的活力在种公牛之间存在差异。代谢物是各种代谢途径的终产物，精浆代谢物对精子冷冻保存的贡献仍不清楚。知识库中的这些空白令人担忧，因为它们阻碍了低温生物学基础科学的进展以及公牛生育能力的提高。本研究的目的是检验精浆氨基酸与公牛精子冷冻能力相关的假设。为实现这一目标，使用气相色谱 - 质谱联用仪（GC - MS）对7头冷冻能力良好（GF）的公牛和6头冷冻能力较差（PF）的公牛的精浆中的氨基酸浓度进行了定量分析。进行了多变量和单变量分析以确定潜在的冷冻能力生物标志物。使用生物信息学工具对鉴定出的氨基酸进行了通路和网络分析。通过分析和解释结果，我们证明谷氨酸是公牛精浆中含量最丰富的氨基酸，平均浓度为3366±547.3 nM，约占总氨基酸的53%。其他最主要的氨基酸是丙氨酸、甘氨酸和天冬氨酸，平均浓度分别为1053±187.9、429.8±57.94和427±101.3 nM。Pearson相关分析表明苯丙氨酸浓度与解冻后活力显著相关（ = 0.57， - 值 = 0.043）。在其他氨基酸之间也发现了显著相关性。此外，偏最小二乘判别分析（PLS - DA）双标图表明GF组和PF组之间有明显分离。苯丙氨酸的VIP得分最高，在GF组中比在PF组中更丰富。此外，通路和网络分析表明苯丙氨酸参与氧化还原酶和抗氧化反应。尽管单变量分析未显示两组之间氨基酸浓度存在显著差异，但这些发现意义重大，因为它们表明了氨基酸在精浆中的潜在重要作用，从而为低温生物学和生殖生物技术的基础科学奠定了基础。
