Grupo Fisiopatologia e Biotécnicas da Reprodução Animal (FiBRA-UFPel), Faculdade de Veterinária, Universidade Federal de Pelotas, Pelotas, Brasil.
Progen Inseminação Artificial, Dom Pedrito, Brasil.
Reprod Domest Anim. 2024 May;59(5):e14585. doi: 10.1111/rda.14585.
The study investigated midpiece defects in sperm from a 5-year-old Brangus bull with a high rate of semen batch rejection, due to morphologically abnormal sperm, with no reduction in sperm kinematics. A comprehensive evaluation was conducted over a 16-month period, involving 28 ejaculates. Notably, despite the high proportion of midpiece defects (average 37.73%, from 3% to 58%), the study revealed stable sperm production, with no discernible differences in the kinematic data before and after cryopreservation. Electron microscopy identified discontinuities in the mitochondrial sheath, characteristic of midpiece aplasia (MPA). The anomalies were attributed to be of genetic origin, as other predisposing factors were absent. Additionally, the electron microscopy unveiled plasma membrane defects, vacuoles and chromatin decondensation, consistent with previous findings linking acrosome abnormalities with midpiece defects. The findings underscored the necessity of conducting thorough laboratory evaluations before releasing cryopreserved semen for commercialization. Despite substantial morphological alterations, the initial semen evaluation data indicated acceptable levels of sperm kinematics, emphasizing the resilience of sperm production to severe morphological changes. This case report serves as a contribution to the understanding of midpiece defects in bull sperm, emphasizing the need for meticulous evaluation and quality control in semen processing and commercialization.
该研究调查了一头 5 岁布尔冈公牛的中段缺陷，该公牛由于精子形态异常而导致精液批次大量拒收，但其精子运动学没有降低。在 16 个月的时间里进行了全面评估，涉及 28 次射精。值得注意的是，尽管中段缺陷比例很高（平均 37.73%，范围为 3%至 58%），但研究显示精子产量稳定，冷冻保存前后的运动学数据没有明显差异。电子显微镜发现线粒体鞘的不连续性，这是中段发育不全（MPA）的特征。这些异常被认为是遗传起源的，因为没有其他潜在的因素。此外，电子显微镜还揭示了质膜缺陷、空泡和染色质解凝聚，这与先前发现的顶体异常与中段缺陷有关的研究结果一致。这些发现强调了在商业化之前对冷冻保存精液进行彻底的实验室评估的必要性。尽管存在大量的形态改变，但最初的精液评估数据表明精子运动学处于可接受水平，这强调了精子生产对严重形态变化的恢复能力。本病例报告有助于理解公牛精子的中段缺陷，并强调在精液处理和商业化过程中需要进行细致的评估和质量控制。
