Oxidative stability, fatty acid composition and health lipid indices of Longissimus dorsi muscle from Aberdeen Angus steers produced in different feeding systems

The aim of this study was to evaluate the oxidative and anti-oxidative status of unaged and aged Longissimus dorsi (LD) muscle obtained from a commercial abattoir. Also, fatty acid composition and calculated health lipid indices of meat were compared. Animals slaughtered were Aberdeen Angus steers raised in three typical feeding systems of Uruguay: (1) Pasture (n=10), (2) Pasture + Supplement (P+S) with corn grain (n=10), and (3) Feedlot (n=10). Feeding had no effect on lipid and protein oxidation but the antioxidant enzymes activities were affected as follows: superoxide dismutase (SOD): Pasture, Feedlot > P+S; catalase: Pasture > P+S, Feedlot; glutathione peroxidase (GPx): Feedlot > P+S > Pasture. Total antioxidant potential, determined by Fenton reaction, was higher in aged meat from Pasture compared with aged meat from Feedlot. Meat from Pasture and P+S presented a higher eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and total n-3 content and a lower lipid content, n-6/n-3 ratio and trombogenic index compared to meat from Feedlot. In conclusion, Pasture seems to produce a more resistant meat against induced oxidation processes, particularly after ageing, and a healthier meat together with meat from P+S system, regarding fatty acid composition and lipid indices, compared to Feedlot.