Meat differentiation between pasture-fed and concentrate-fed sheep/goats by liquid chromatography quadrupole time-of-flight mass spectrometry combined with metabolomic and lipidomic profiling

Animal feeding method is a crucial factor in influencing meat quality. Consumers would preferentially select meat obtained from pasture-fed animals. In this study, an untargeted metabolomic and lipidomic method based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) combined with chemometric analysis was utilized to investigate the differences between meat from free-range and intensively-fed sheep/goats. Distinct separation between these two kinds of sheep/goats meat obtained were identified by principal component analysis. Analysis of variance, fold change and orthogonal projection to latent structures discriminant analysis were then conducted to determine specific potential markers. A total of 46 potential markers were selected according to online chemical databases. The support vector machine (SVM) method was used to process the responses of the selected potential markers, and the results of metabolomics and lipidomics from an additional 59 samples revealed the discrimination rate of 89.3% and 98.3%. These findings provided a basis for differentiation of meat from sheep/goats fed in the two methods.