The castration of bulls increases the intramuscular fat (IMF) content in skeletal muscle. However, the biological processes of IMF accumulation in skeletal muscle after castration are not completely understood at the molecular level. This study examined the global transcriptomic changes in the longissimus thoracis muscle (LT) of bulls following castration using RNA sequencing (RNA‐Seq) and identified new genes or pathways associated with beef quality. Ten bulls and 10 steers castrated at 6 months of age were slaughtered at 26 and 32 months of age respectively. For transcriptome analysis, six LT samples from three bulls and three steers were selected based on age, carcass weight, carcass quantity and beef quality grades. Using RNA‐Seq, transcriptomic profiles of the LT were compared between bulls and steers. In all, 640 of the 18,027 genes identified through RNA‐Seq were differentially expressed genes (DEGs) between bulls and steers. Pathway analysis of these 640 DEGs showed significant (p < .05) changes in seven Kyoto Encyclopedia of Genes and Genomes pathways, and the most significant terms were complement and coagulation cascade pathways. The transcriptomic expression patterns of 10 genes in the complement and coagulation cascades were validated using all animals through quantitative real‐time polymerase chain reaction analysis. In conclusion, transcriptome changes associated with the complement and coagulation cascade pathways provide novel insights into understanding molecular mechanisms responsible for IMF accumulation following castration in beef cattle.

中文翻译：

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与阉割后韩国牛胸最长肌脂肪沉积相关的转录组变化。

公牛的阉割会增加骨骼肌中的肌内脂肪 (IMF) 含量。然而，在分子水平上尚未完全了解去势后骨骼肌中 IMF 积累的生物学过程。这项研究检查了胸最长肌的整体转录组变化使用 RNA 测序 (RNA-Seq) 分析阉割后公牛的肌肉 (LT)，并鉴定出与牛肉品质相关的新基因或途径。在 6 个月大时阉割的 10 头公牛和 10 头公牛分别在 26 和 32 个月大时被屠宰。对于转录组分析，根据年龄、胴体重量、胴体数量和牛肉质量等级选择了来自三头公牛和三头公牛的六个 LT 样本。使用 RNA-Seq，在公牛和公牛之间比较了 LT 的转录组学特征。总之，通过 RNA-Seq 鉴定的 18,027 个基因中有 640 个是公牛和公牛之间的差异表达基因（DEG）。这些 640 DEG 的通路分析显示显着（p < .05) 七个京都基因和基因组百科全书途径的变化，最重要的术语是补体和凝血级联途径。通过定量实时聚合酶链反应分析，使用所有动物验证补体和凝血级联中 10 个基因的转录组表达模式。总之，与补体和凝血级联通路相关的转录组变化为了解负责肉牛阉割后 IMF 积累的分子机制提供了新的见解。