Identification of relevant in vivo biomarkers for fertility remains a challenge for the livestock industry. Concentrations of the small peptide hormone oxytocin (OXT), involved in male reproductive function and present in the seminal plasma (SP) of several species could be a robust one. This study characterized concentrations of SP-OXT in ejaculates from boars used in artificial insemination (AI) programs aiming to evaluate its relationship with sperm quality variables and in vivo fertility of their liquid-stored AI-semen. Seminal OXT concentrations (ng/mL) were measured in 169 ejaculates from 61 boars of the Duroc, Pietrain, Landrace and Large White breeds using a direct competitive immunoassay test based on AlphaLISA® technology. Ejaculate (ejaculate volume, sperm concentration, total sperm count) and sperm parameters (motility, viability, intracellular generation of reactive oxygen species, plasma membrane fluidity) were assessed at 0 h and 72 h in AI-semen samples stored at 17 °C. In vivo fertility included only 18 Large White and Landrace boars whose AI-semen was used to inseminated > 100 sows and evaluated both farrowing rate and litter size of 3,167 sows. The results showed that SP-OXT differed between boars and between ejaculates within boar (P < 0.05) but not between breeds (Duroc, Pietrain, Landrace and Large White). Ejaculates with higher SP-OXT concentration/mL (hierarchically grouped; P < 0.001) had larger volume and came from younger boars (P < 0.05). Ejaculates of boars showing positive farrowing rate deviation exhibited higher (P < 0.05) SP-OXT concentration/mL than those with negative farrowing rate deviation. The SP concentrations of OXT are boar, ejaculate and age dependent, and positively related with ejaculate volume and farrowing rates of liquid-stored semen AI-doses.

中文翻译：

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猪精浆中的催产素与受精母猪体内生育力呈正相关

鉴定与生育相关的体内生物标志物仍然是畜牧业面临的挑战。小肽激素催产素 (OXT) 的浓度与雄性生殖功能有关，并且存在于几个物种的精浆 (SP) 中，可能是一个强大的浓度。这项研究表征了人工授精 (AI) 计划中使用的公猪精液中 SP-OXT 的浓度，旨在评估其与精子质量变量和液体储存的 AI 精液的体内生育力的关系。使用基于 AlphaLISA® 技术的直接竞争性免疫分析测试，测量了来自 61 头杜洛克、皮特兰、长白和大白种公猪的 169 只精液中的精液 OXT 浓度 (ng/mL)。射精（射精量、精子浓度、精子总数）和精子参数（活力、活力、细胞内活性氧的产生、质膜流动性）在 0 小时和 72 小时时在 17°C 下储存的 AI 精液样品中进行评估。体内生育力仅包括 18 头大型白公猪和长白公猪，它们的 AI 精液用于对 > 100 头母猪进行授精，并评估了 3,167 头母猪的分娩率和窝产仔数。结果表明，SP-OXT 在公猪之间和公猪体内射精之间存在差异（P < 0.05），但在品种（杜洛克、皮特兰、长白和大白）之间没有差异。具有较高 SP-OXT 浓度/mL 的精液（分层分组；P < 0.001）具有更大的体积并且来自更年轻的公猪（P < 0.05）。表现出正分娩率偏差的公猪的精液比那些具有负分娩率偏差的公猪的精液表现出更高（P < 0.05）SP-OXT浓度/mL。OXT 的 SP 浓度是公猪，