Range-based finishing enhances omega-3 fatty acids and forage-derived metabolites in bison meat across a seven-treatment comparison

Abstract Background Finishing practices influence the biochemical composition of bison ( Bison bison ) meat, with potential implications for animal health and human nutrition. This study evaluated seven representative finishing systems spanning a range of extensive and intensive production systems, with additional contrasts in forage diversity, corn supplementation, and stocking density to determine their effects on the fatty acid and phytonutrient profiles of bison striploins ( M. longissimus lumborum ). Treatments included range-finished bison grazing either diverse native pastures (~200 plant species) or lower-diversity pastures (~90 plant species), with or without corn supplementation, as well as pen-finished bison managed under varying feed formulations and stocking densities, including a conventional total mixed ration (TMR) group. Fatty acids were analyzed by gas chromatography–flame ionization detection (GC-FID), and targeted metabolomic profiling of phytonutrient-derived metabolites was performed using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Results Range-finished bison exhibited higher concentrations of alpha-linolenic acid (ALA; C18:3n-3; P < 0.0001), docosapentaenoic acid (DPA; C22:5n-3; P < 0.0001), and docosahexaenoic acid (DHA; C22:6n-3; P < 0.0001), and lower n-6:n-3 ratios (2.8–3.6) than pen-finished bison (5.0–7.3; P < 0.0001). Metabolomic profiling revealed enrichment of hippuric acid, catechol, and shikimic acid (candidate biomarkers associated with forage intake and polyphenolic metabolism) in range-finished systems, whereas 3-(4-hydroxyphenyl)lactic acid, a potential grain-associated metabolite, was higher in pen-finished bison than in the unsupplemented range-finished systems (all P < 0.05). Conclusions Range-finished systems enhanced omega-3 fatty acid and phytonutrient-related metabolite profiles, whereas the conventional TMR feedlot treatment yielded the lowest levels and the free-choice corn-and-hay pen system yielded an intermediate profile. Overall, the clearest nutritional contrast was between range-finished and pen-finished systems, whereas differences attributable to forage diversity or stocking density were comparatively modest. These findings indicate that finishing system strongly influences the biochemical composition of bison meat, although comparisons involving the conventional TMR feedlot treatment should be interpreted cautiously because that group originated from a separate breeding herd.