Universidade Estadual Paulista, FCAV/UNESP, Jaboticabal, São Paulo, Brazil.
Senepol 3G, Barretos, São Paulo, Brazil.
Theriogenology. 2021 Feb;161:98-107. doi: 10.1016/j.theriogenology.2020.11.019. Epub 2020 Nov 28.
In cattle, in vitro embryo production (IVEP) is an important reproductive biotechnology responsible for the rapid expansion of the Senepol breed in our country. This breed has shown important results when used in crossbreeding and estimate IVEP in Senepol based on seminal analysis would be valuable for the semen cryopreservation industry, research institutes and breeders. Combining the evaluation of sperm subpopulations with analysis of other sperm attributes may help to improve fertility predictions in cattle. Therefore, the objectives of the present study were to: 1) identify and characterize motile sperm subpopulations in cryopreserved Senepol semen following the washing process carried out before in vitro fertilization, and 2) to determine an model for estimate IVEP based on sperm subpopulations in conjunction with other sperm quality analyzes. Samples of 38 cryopreserved semen from 28 Senepol bulls, chosen based on retrospective data from 386 IVEP routines, underwent the semen washing and were evaluated by the computer-assisted sperm analysis system. Sperm morphology was evaluated by wet preparation technique, and plasma and acrosomal membranes integrity, mitochondrial potential, oxidative status and chromatin resistance were analyzed by flow cytometry. After multivariate analysis of principal components and grouping, three sperm subpopulations were identified: SBP1 (fast and progressive motility), SBP2 (hyperactivated motility) and SBP3 (slow non-progressive motility). After categorization of IVEP in high, medium and low embryo yield, logistic regression analysis was applied to associate the results of subpopulations and other sperm quality variables with IVEP. The SBP1 and SBP2 variables affected embryo production, and an IVEP estimation model was generated for Senepol bulls based on these two subpopulations: embryo yield = 0.1563 + 0.0328 (SBP1) + 0.0173 (SBP2). SBP1 and SBP2 represents the absolute value of the percentage of subpopulations in semen. If the calculated value (by this equation) is close to 1, the embryo yield will be low; if is close to 2, will be medium; if is close to 3, will be high. In conclusion, three subpopulations were found for Senepol semen and, despite all analyzed variables, only SBP1 and SBP2 were included in the model to estimate IVEP in this breed.
在牛中，体外胚胎生产（IVEP）是一项重要的生殖生物技术，负责我国森佩尔品种的快速扩张。当用于杂交时，该品种已经显示出重要的结果，并且估计森佩尔的 IVEP 基于精液分析对于精液冷冻保存行业、研究所以及饲养者来说将是有价值的。结合评估精子亚群与分析其他精子属性可以帮助提高牛的生育力预测。因此，本研究的目的是：1）鉴定和描述在体外受精前进行洗涤处理后冷冻保存的森佩尔精液中的运动精子亚群，2）建立一种基于精子亚群与其他精子质量分析相结合的估计 IVEP 的模型。根据 386 次 IVEP 常规的回顾性数据，选择了来自 28 头森佩尔公牛的 38 份冷冻精液样本进行精液洗涤，并通过计算机辅助精子分析系统进行评估。通过湿制备技术评估精子形态，并通过流式细胞术分析精子质膜和顶体膜完整性、线粒体潜能、氧化状态和染色质抗性。在进行主成分和分组的多元分析后，鉴定出了三个精子亚群：SBP1（快速和渐进运动）、SBP2（超激活运动）和 SBP3（缓慢非渐进运动）。在对高、中、低胚胎产量进行分类后，应用逻辑回归分析将亚群和其他精子质量变量的结果与 IVEP 相关联。SBP1 和 SBP2 变量影响胚胎生产，并且基于这两个亚群为森佩尔公牛生成了一个 IVEP 估计模型：胚胎产量=0.1563+0.0328（SBP1）+0.0173（SBP2）。SBP1 和 SBP2 表示精液中亚群的绝对值百分比。如果计算值（通过此方程）接近 1，则胚胎产量将较低；如果接近 2，则为中等；如果接近 3，则为高。总之，在森佩尔精液中发现了三个亚群，尽管分析了所有变量，但只有 SBP1 和 SBP2 被纳入该模型来估计该品种的 IVEP。
