By affecting the ovarian pool of follicles and their enclosed oocytes, heat stress has an impact on dairy cow fertility. This study aimed to determine how heat shock (HS) during in vitro maturation affected the ability of the bovine cumulus-oocyte complexes (COCs) to develop, as well as their metabolism of amino acids (AAs). In this study, COCs were in vitro matured for 23 h at 38.5 °C (control; n = 322), 39.5 °C (mild HS (MHS); n = 290), or 40.5 °C (severe HS (SHS); n = 245). In comparison to the control group, the MHS and SHS groups significantly decreased the percentage of metaphase-II oocytes, as well as cumulus cell expansion and viability. The SHS decreased the rates of cleavage and blastocyst formation in comparison to the control and MHS. Compared to the control and MHS-COCs, the SHS-COCs produced significantly more phenylalanine, threonine, valine, arginine, alanine, glutamic acid, and citrulline while depleting less leucine, glutamine, and serine. Data showed that SHS-COCs had the highest appearance and turnover of all AAs and essential AAs. Heat shock was positively correlated with the appearance of glutamic acid, glutamine, isoleucine, alanine, serine, valine, phenylalanine, and asparagine. Network analysis identified the relationship between HS and alanine or glutamic acid, as well as the relationship between blastocyst and cleavage rates and ornithine. The findings imply that SHS may have an impact on the quality and metabolism of AAs in COCs. Moreover, the use of a multistep analysis could simply identify the AAs most closely linked to HS and the developmental competence of bovine COCs.

通过影响卵泡的卵巢池及其封闭的卵母细胞，热应激会影响奶牛的生育力。本研究旨在确定体外成熟过程中的热休克 (HS) 如何影响牛卵丘-卵母细胞复合物 (COC) 的发育能力及其氨基酸 (AA) 代谢。在本研究中，COC 在 38.5 °C（对照；n = 322）、39.5 °C（轻度 HS (MHS)；n = 290）或 40.5 °C（重度 HS (SHS)；n = 290）下体外成熟 23 小时。 n = 245）。与对照组相比，MHS 和 SHS 组显着降低了中期 II 卵母细胞的百分比以及卵丘细胞的扩张和活力。与对照和 MHS 相比，SHS 降低了卵裂和囊胚形成的速率。与对照和 MHS-COC 相比，SHS-COC 产生显着更多的苯丙氨酸、苏氨酸、缬氨酸、精氨酸、丙氨酸、谷氨酸和瓜氨酸，同时消耗较少的亮氨酸、谷氨酰胺和丝氨酸。数据显示，SHS-COCs 在所有 AA 和必需 AA 中出现率和周转率最高。热休克与谷氨酸、谷氨酰胺、异亮氨酸、丙氨酸、丝氨酸、缬氨酸、苯丙氨酸和天冬酰胺的出现呈正相关。网络分析确定了 HS 与丙氨酸或谷氨酸之间的关系，以及囊胚与卵裂率和鸟氨酸之间的关系。研究结果表明，SHS 可能对 COC 中 AA 的质量和代谢产生影响。此外，使用多步骤分析可以简单地识别与 HS 和牛 COC 发育能力最密切相关的 AA。