Multi-omics insights into the metabolic basis of variation in 4-alkyl branched-chain fatty acids in meat from Chinese sheep breed

We quantified 4-methyloctanoic acid (4-MOA), 4-ethyloctanoic acid (4-EOA), and 4-methylnonanoic acid (4-MNA) and integrated muscle metabolomics with public multi-omics data to explore the metabolic basis of breed differences. BCFA deposition varied among breeds.

The three target compounds were undetectable in Altay and Turpan sheep, whereas Hu and Tan sheep had detectable levels of at least two compounds. In Hu sheep, 4-MOA and 4-EOA concentrations were approximately 14.4 and 12.5 times those in Tan sheep, respectively (p < 0.001). Metabolomic and integrative analyses identified differences in amino acid, lipid, and energy metabolism, with branched-chain amino acid (BCAA) degradation, propanoate metabolism, and the tricarboxylic acid (TCA) cycle recurring across comparisons.