Although single layer centrifugation (SLC) selects robust spermatozoa from stallion semen, the effect of individual variation has not been studied in detail. The objective of this study was to determine the variation among stallions in the effects of SLC on sperm quality during cooled storage for up to 48 hr. Semen samples from seven stallions (18 ejaculates) were split, with one portion being used for SLC and the other serving as a control (CON). Sperm quality (kinematics, reactive oxygen species (ROS) production, membrane integrity (MI) and chromatin integrity) were analysed at 0, 24 and 48 hr using computer-assisted sperm analysis and flow cytometry. Sperm quality was better in SLC than in CON at all timepoints, especially chromatin integrity and MI (p < .0001 for both), and some categories of ROS production (e.g. proportion of live hydrogen peroxide negative spermatozoa, p < .0001), but the degree of improvement varied among stallions and type of ROS (p < .05–p < .0001). Total and progressive motility were also better in SLC samples than in CON at 24 and 48 hr (p < .0001), although the effect on sperm kinematics varied. The interaction of treatment, time and stallion was not significant. In conclusion, sperm quality was better in SLC samples than in CON, although there was considerable individual variation among stallions. The improvement in sperm quality, particularly in chromatin integrity, was clearly beneficial, and therefore the use of this technique would be warranted for all stallion semen samples.

中文翻译：

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单层离心后种马间精子质量的变化

尽管单层离心 (SLC) 从种马精液中选择了健壮的精子，但尚未详细研究个体变异的影响。本研究的目的是确定在长达 48 小时的冷却储存期间 SLC 对精子质量影响的种马之间的差异。将来自七匹种马（18 只精液）的精液样本分开，一份用于 SLC，另一份用作对照 (CON)。精子质量（运动学、活性氧 (ROS) 产生、膜完整性 (MI) 和染色质完整性）在 0、24 和 48 小时时使用计算机辅助精子分析和流式细胞术进行分析。SLC 的精子质量在所有时间点都比 CON 好，尤其是染色质完整性和 MI（p < .0001），以及某些类别的 ROS 产生（例如活过氧化氢阴性精子的比例，p  < .0001），但改善程度因种马和 ROS 类型而 异（p < .05– p  < . 0001）。在 24 小时和 48 小时时，SLC 样品中的总运动性和渐进性运动性也比 CON 中更好（p < .0001)，尽管对精子运动学的影响各不相同。处理、时间和种马之间的相互作用不显着。总之，尽管种马之间存在相当大的个体差异，但 SLC 样本中的精子质量优于 CON。精子质量的提高，特别是染色质完整性的提高，显然是有益的，因此所有种马精液样本都需要使用这种技术。