Abstract

The growing demand for high-quality protein and sustainable production systems has increased interest in characterizing the nutritional value of beef from pasture-based systems. This study aimed to determine the fatty acid composition and to identify and quantify the lipidomic profile of the Longissimus dorsi muscle in Aberdeen Angus steers raised under three grass-fed systems in southern Chile: conventional (G1), free-range (G2), and regenerative (G3). Fatty acid profiles were analyzed using gas chromatography with flame ionization detection (GC-FID). Principal component analysis revealed a clear separation between G1, G2 and G3 systems, indicating that lipid variability is strongly influenced by the production system. Notably, G2 and G3 exhibited more favorable profiles of functional fatty acids. Lipidomic analysis using LC-MS/MS identified 103 lipids in positive ionization mode and 39 in negative mode, with significant differences in lipid composition among the systems. The Regenerative system promoted a healthier lipid profile, characterized by higher levels of polyunsaturated fatty acids and bioactive lipids. These findings provide new insights into how production systems influence the nutritional quality of beef and underscore the potential of regenerative agriculture to enhance human health through dietary intake. © 2025