Effect of grazing alfalfa on α -tocopherol content and FA composition in Longissimus and Semitendinosus muscles of light lambs
2014
Molino, F | Blanco, M | González-Calvo, L | Ripoll, G | Calvo, J H | Joy, M
Grazing can increase α-tocopherol content in the lamb muscle without additional expenses com- pared with tocopheryl acetate supplementation and modify the fatty acid (FA) profile. The aim of the study was to compare the effect of alfalfa grazing on α-tocopherol and FA composition of Longissimus thoracis (LT) and Semitendinosus (ST) muscles. Twenty single reared male lambs of Rasa Aragonesa breed were used. A group of weaned lambs was indoors and fed concentrate and a group of suckling lambs was grazing alfalfa continuously with their dams. The LT and ST muscles were extracted to determine α-tocopherol content and FA composition. In both muscles, grazing lambs had more than 2-fold higher α-tocopherol content, C18:2n- 6tt, C18:3n-3, C20:5n-3, C22:5n-3, C22:6n-3 and total n-3 FA contents (P less than 0.001) but lower n-6:n-3 ratio (P less than 0.001) than concentrate-fed lambs. In both muscles, grazing lambs had lower Monounsaturated FA than concentrate-fed lambs. Generally, grazing had a greater impact on n-3 FA and α-tocopherol content in ST than in LT muscle. Grazing improved the n-6:n-3 ratio and could increase the meat shelf-life. The α-toco- pherol content and individual n-3 FA could be used to authenticate forage intake
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