Transcriptome analysis reveals intestinal gene expression and metabolic pathways in yaks.

The yak, a ruminant species native to high-altitude plateaus, serves as a vulnerable model for studying adaptation to extreme environments. Exposed to hypoxia, low temperatures, and strong ultraviolet radiation, yaks have evolved unique physiological mechanisms to thrive under such conditions. Among its organs, the intestine is a crucial metabolic organ and plays a key role in environmental adaptation. Therefore, this study systematically compared the transcriptional regulatory mechanisms of the small and large intestine between yaks and cattle, thereby revealing the metabolic mechanisms underlying the high-altitude adaptation of yaks. The results showed that the expression of several key metabolic genes, including IDO1, KYNU (tryptophan metabolism), ACSL1 (lipid metabolism), and ABCG2 (vitamin transport), was significantly upregulated in the yak small intestine. This indicates that the yak small intestine has stronger physiological potential in nutrient metabolism and barrier function. In the large intestine, the expression of key genes in pathways such as lipid metabolism (PLA2), detoxification (UGT), cAMP signaling (ADCY, CREB3L), and bile secretion (ABCC) was significantly upregulated, indicating that the yak possesses unique physiological advantages in energy regulation and maintaining intestinal homeostasis. This study systematically elucidates the metabolic mechanisms of the yak intestine under the extreme conditions of the plateau, providing a basis for in-depth analysis of ruminant intestinal function and molecular breeding.