Effect of High Altitude on Serum Biochemical Parameters, Immunoglobulins, and Rumen Metabolism of Sanhe Heifers

Abstract

Rumen metabolism is closely related to feed utilization and the environmental adaptability of cows. However, information on the influence of altitude on ruminal metabolism is limited. Our study aimed to investigate differences in rumen metabolism and blood biochemical indicators among Sanhe heifers residing at various altitudes. A total of 20 serum and ruminal fluid samples were collected from Sanhe heifers in China, including those from Hulunbeier City (approximately 700 m altitude; 119°57′ E, 47°17′ N; named LA) and Lhasa City (approximately 3650 m altitude; 91°06′ E, 29°36′ N; named HA). Compared with LA heifers, HA heifers had higher levels of serum cortisol, glucose, and blood urea nitrogen (p < 0.05) and lower Ca2+ concentrations (p < 0.05). Using liquid chromatography–mass spectrometry (LC–MS)-based untargeted metabolomic technology, we identified a significant difference in 312 metabolites between the LA and HA groups. Metabolic pathway analysis, based on significantly different rumen metabolites, identified 20 enriched metabolic pathways within hierarchy III, which are encompassed within 6 broader metabolic pathways in hierarchy I. This study constitutes the first elucidation of the altitudinal adaptation mechanism of ruminants from the perspective of rumen metabolism, thereby offering a novel angle for investigating high-altitude adaptation in both humans and animals.