Rheotaxis of sperm using a microfluidic device was explored in human, mice and bull. However, the rheotaxis of ram sperm and its role in fertility are unknown. Herein, we described the sperm rheotaxis in ram using microfluidic devices and focused on rheotaxis as potential markers of in vivo fertility. Computer‐assisted sperm analysis (CASA) with controlled flow velocity was used to explore the kinematic parameters of sperm, total motility and positive rheotaxis (PR). The percentage of PR was defined as the number of PR sperm cells over the number of motile sperm cells. Then, according to the percentage of PR sperm, rams were classified into two groups; sperm with ≥40% PR and <40% PR, although the two ram groups showed similar total motility and kinematic values of sperm evaluated by CASA (p > .05). Two groups of rams mated one hundred thirty ewes naturally (10 ewes/ram). In the results, the pregnancy rate was higher in ≥40% PR (94.4%) than in <40% PR (42.5%, p < .05) after natural mating. Besides, the pregnancy loss was higher in <40% PR (33.3%) than in >40% PR group (8.1%, p < .05). In conclusion, the PR examination in semen can contribute to evaluate the reproductive performance of ram that will provide valuable insights into the semen evaluation.

中文翻译：

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用微流控技术分析公羊精子流变对生育的影响。

在人，小鼠和公牛中探索了使用微流控装置进行的精子流变。但是，ram精子的流变性及其在生育力中的作用尚不清楚。在这里，我们描述了使用微流控设备在公羊精子流变，并专注于流变作为体内可育性的潜在标志。使用计算机辅助精子分析（CASA）和可控制的流速来研究精子的运动学参数，总运动性和正流变性（PR）。PR的百分比定义为PR精子细胞数超过活动精子细胞数。然后，根据PR精子的百分率，将公羊分为两组。PR≥40％PR <40％的精子，尽管两个公羊组表现出相似的总活力和CASA评估的精子运动学值（p > .05）。两组公羊自然交配了一百三十头母羊（每头公羊十只母羊）。结果表明， 自然交配后，≥40％PR（94.4％）的妊娠率高于<40％PR（42.5％，p <.05）的妊娠率。此外，PR ＜40％组的妊娠流失率（33.3％）高于PR> 40％组的妊娠流失率（8.1％，p  <.05）。总之，精液中的PR检查有助于评估公羊的生殖性能，这将为精液评估提供有价值的见解。