Multi-omics analysis reveals flavor differences in Xinjiang brown beef with varying intramuscular fat contents

Beef flavor plays a crucial role in consumer preference, yet research on this trait has been limited by past technological constraints. Intramuscular fat (IMF) is a key determinant of beef quality, influencing taste, marbling, and overall flavor. Xinjiang brown cattle (XBC), an indigenous breed from northern Xinjiang, China, presents significant variation in meat quality, with IMF content ranging from 0.2 % to 4.3 % within the population. This variation suggests strong potential for breeding improvement. In this study, we selected 82 XBC for slaughter and meat quality analysis, categorizing them based on IMF content. Using two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF MS), we analyzed volatile flavor compounds across different beef cuts (Longissimus dorsi, Semitendinosus, Supraspinatus). Our results showed that beef with higher IMF levels exhibited enhanced flavor profiles, characterized by sweet, green, fruity, and waxy notes, while castrated bulls displayed the weakest flavor intensity. Metabolomic analysis further revealed significant differences in flavor substances between high and low IMF content beef. RNA-Seq analysis identified key genes (AQP4, FZD2, FADS1, BPG1, CEBPD, FABP4) associated with flavor formation, offering valuable insights for breeding strategies aimed at improving XBC meat quality. This comprehensive study provides a robust theoretical foundation for advancing the genetic improvement of XBC.