Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, College of Life Science, Northeast Agricultural University, Harbin, 150030, Heilongjiang, PR China.
Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, College of Life Science, Northeast Agricultural University, Harbin, 150030, Heilongjiang, PR China; Engineering Research Center of Intelligent Breeding and Feeding of Pig in Northern Cold Region, Ministry of Education, Northeast Agricultural University, Harbin, 150030, Heilongjiang, PR China.
Theriogenology. 2023 Aug;206:28-39. doi: 10.1016/j.theriogenology.2023.04.016. Epub 2023 Apr 27.
The resistance of sperm to freezing varies widely among boars. The semen ejaculate of different boars can be grouped into poor freezability ejaculate (PFE) and good freezability ejaculate (GFE). In this study, five Yorkshire boars each of the GFE and PFE were selected by comparing the changes in sperm motility before and after cryopreservation. Firstly, we found that the sperm plasma membrane of the PFE group showed weak integrity after PI and 6-CFDA staining. Then the electron microscopy results verified that the plasma membrane condition of all segments of GFE was better than that of PFE segments. Furthermore, the lipid composition of sperm plasma membranes in GPE and PFE sperm was analyzed by using mass spectrometry, and 15 lipids showed differences between the two groups. Among those lipids, only phosphatidylcholine (PC) (14:0/20:4) and phosphatidylethanolamine (PE) (14:0/20:4) were higher in PFE. The remaining lipid contents, including those of dihydroceramide (18:0/18:0), four hexosylceramides (18:1/20:1, 18:0/22:1, 18:1/16:0, 18:1/18:0), lactosylceramide (18:1/16:0), two hemolyzed phosphatidylethanolamines (18:2, 20:2), five phosphatidylcholines (16:1/18:2, 18:2/16:1, 14:0/20:4, 16:0/18:3, 18:1/20:2), and two phosphatidylethanolamines (14:0/20:4, 18:1/18:3), were all positively correlated with resistance to cryopreservation (p < 0.05, r > 0.6). Moreover, we analyzed the metabolic profile of sperm using untarget metabolomic. KEGG annotation analysis revealed that the altered metabolites were mainly involved in fatty acid biosynthesis. Finally, we determined that the contents of oleic acid, oleamideetc, N8-acetylspermidine etc., were different between GFE and PFE sperm. In summary, the different lipid metabolism levels and long-chain polyunsaturated fatty acids (PUFAs) in plasma membrane may be key factors contributing to differences in sperm resistance to cryopreservation among boars.
猪精子对冷冻的抵抗力差异很大。不同公猪的精液可分为冷冻不良可育性精液（PFE）和冷冻良好可育性精液（GFE）。在这项研究中，通过比较冷冻前后精子活力的变化，选择了 5 头具有良好冷冻能力的约克夏猪和 5 头冷冻不良的约克夏猪。首先，我们发现 PFE 组精子质膜在 PI 和 6-CFDA 染色后显示出较弱的完整性。然后，电子显微镜结果证实，GFE 各段的质膜状况均优于 PFE 段。此外，通过质谱法分析了 GPE 和 PFE 精子质膜的脂质组成，两组之间有 15 种脂质存在差异。在这些脂质中，只有 PFE 中的磷脂酰胆碱（PC）（14:0/20:4）和磷脂酰乙醇胺（PE）（14:0/20:4）较高。其余脂质含量，包括二氢神经酰胺（18:0/18:0）、四种己糖神经酰胺（18:1/20:1、18:0/22:1、18:1/16:0、18:1/18:0）、乳糖神经酰胺（18:1/16:0）、两种溶血磷脂酰乙醇胺（18:2、20:2）、五种磷脂酰胆碱（16:1/18:2、18:2/16:1、14:0/20:4、16:0/18:3、18:1/20:2）和两种磷脂酰乙醇胺（14:0/20:4、18:1/18:3），均与冷冻抗性呈正相关（p<0.05，r>0.6）。此外，我们使用非靶向代谢组学分析了精子的代谢谱。KEGG 注释分析表明，改变的代谢物主要参与脂肪酸的生物合成。最后，我们确定了 GFE 和 PFE 精子中油酸、油酰胺等、N8-乙酰亚精胺等的含量不同。总之，质膜中不同的脂质代谢水平和长链多不饱和脂肪酸（PUFAs）可能是导致猪精子冷冻抗性差异的关键因素。
