Breed-Associated Differences in Longissimus Dorsi Muscle Lipid Composition in Saanen Dairy Goat, Shaanbei White Cashmere Goat, and Tan Sheep, with Implications for Flavour Formation

Goat and sheep meat are highly regarded in the market for their unique flavor qualities. In this study, lipidomics technology was employed to compare the lipid differences in the longissimus dorsi muscle among 8-month-old Saanen dairy goats (DYG, n = 6), Shaanbei white cashmere goats (CAG, n = 6), and Tan sheep (TSH, n = 6). Electronic nose analysis was performed solely on the DYG samples, while the E-nose data for the CAG and TSH groups were referenced against previously published literature. The results indicated that aldehydes, ketones, methyl derivatives, and inorganic sulfides constituted the predominant stable volatile flavor compounds in the DYG muscle. Principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) revealed clear breed-dependent clustering and separation. Cluster analysis revealed that CAG and TSH groups exhibited highly similar lipid expression patterns, whereas the DYG group showed a distinct profile. Specifically, in the DYG group, SM (d18:1/20:3) and S1P (t17:0) were significantly increased, while most triglycerides (TG) were decreased and diglyceride DG (18:0/16:0) was increased. Additionally, multiple phosphatidylcholines (PC) and phosphatidylethanolamines (PE) were significantly reduced in the DYG group. This study revealed unique lipid signatures in the DYG group muscle compared with CAG and TSH groups, providing a theoretical basis for deciphering the lipid regulatory mechanisms underlying meat quality and flavor formation in goats and sheep.