Effect of Rearing System and Seasonality on Fatty Acid Composition in Longissimus lumborum Muscle of Cattle in...

This study aimed to investigate the relationship between rearing systems and seasonality (rainy and dry seasons) on the fatty acid (FA) composition in cattle. Samples of the Longissimus lumborum muscle were obtained from carcasses of 96 castrated Nelore cattle. The samples were lyophilized, and the FA composition was determined by the direct transesterification method and analyzed by gas chromatography. The rearing systems comprise two native pastures (extensive grazing), one cultivated pasture (intensive grazing) and one feedlot. Data were analyzed using generalized linear models, including the fixed effects of production system, season, and their interaction. Regarding polyunsaturated fatty acids (PUFAs), linoleic acid (C18:2n-6), arachidonic acid (C20:4n-6), and α-linolenic acid (C18:3n-3) were the most abundant in all systems. C18:2n-6, C18:3n-3, and C20:4n-6 were higher in pasture systems than in the feedlot, especially in intensive grazing during the rainy season. In the dry season, the scenario was reversed; C18:2n-6 and C20:4n-6 showed a higher concentration in the feedlot system compared to pasture systems. The study demonstrated that pasture production, such as traditional extensive systems, promoted a better ratio of n-6/n-3, contributing to a healthier lipid composition in the meat, when compared to the feedlot. Although the feedlot system has a lower concentration of saturated fatty acids (SFAs), the analysis shows that the extensive system offers a more balanced and healthy FA composition.