Feeding systems differentially shape yak meat quality and flavor profiles on the Qinghai–Tibetan Plateau via rumen microbiota and muscle metabolomics

Yak meat is a key protein source for Tibetan herders. Despite the shift from traditional grazing (TG) to barn feeding (BF) to improve meat supply, mechanisms linking feeding systems to meat quality remain poorly understood. Forty-four yaks were assigned to four BF groups (n=11) with concentrate-to-roughage ratios of 15:85 (BF1), 30:70 (BF2), 45:55 (BF3), and 60:40 (BF4) to evaluate the growth performance and economic return. The BF3 group, representing the BF system, were subsequently compared with TG yaks (n = 11). Multi-omics the effect of feeding systems on rumen microbiota, rumen metabolites, meat nutritional composition, and volatile flavor compounds. The BF3 regimen showed higher growth performance and economic return than lower-concentrate regimens. Compared with TG, BF yaks produced meat with higher essential amino acids and distinct volatile profiles, whereas TG meat contained a more favorable fatty acid with higher polyunsaturated fatty acids (PUFA) levels. Tyrosine metabolism was primarily associated with aromatic compound formation in BF yak meat, whereas butanoate and sulfur metabolism were associated with aldehydes and ketones in TG yaks. Ruminococcus , enriched in BF, was positively linked to muscle essential amino acids, as well as to rumen metabolites related to the accumulation of muscle ketones and alcohols. TG-enriched Prevotella , Segatella , and Paraprevotella were positively correlated with glutamic acid and diverse mono- and PUFA, and were associated with rumen metabolites that related to the formation of aldehydes and organosulfur compounds. This study provides insights into yak production systems and identifies microbial-metabolic associations related to meat quality traits.