Laíza de Kássia Mendes da Conceição, José de Brito Lourenço-Júnior, Jamile Andréa Rodrigues da Silva, Leonel António Joaquim, Mariana Jucá Moraes, Thomaz Cyro Guimarães de Carvalho Rodrigues, Joana do Nascimento Ferreira, Ana Maria Ramos Fontes, Maria Pinheiro Spínola, Érica Coutinho David, Antônio Vinícius Corrêa Barbosa, Bruno Cabral Soares, José António Mestre Prates
Beef is a key source of high-quality proteins, vitamins, and lipids with important nutritional and health implications. Its lipid and antioxidant composition is influenced by both genetic background and feeding system. This study assessed the effects of breed (Nelore vs. Nelore × Angus crossbreed) and diet on cholesterol, lipid-soluble vitamins, and fatty acid profiles in the longissimus lumborum muscle. Thirty-six non-castrated bulls (∼18 months, 300 kg) were finished in a feedlot under three experimental groups defined by planned contrasts: 12 Nelore fed a silage–concentrate diet (G1); 12 crossbred cattle fed the same diet (G2); and 12 Nelore fed a high-grain diet (G3). Cholesterol content did not differ among contrasts (p > 0.05). β-carotene and tocopherols differed mainly in contrasts associated with the feeding system (β-carotene: p = 0.006; α-tocopherol: p < 0.001), while tocotrienols remained stable. Saturated fatty acids (SFA) varied in contrasts associated with diet (p = 0.005), whereas monounsaturated (MUFA) and total n -3 polyunsaturated fatty acids ( n -3 PUFA) differed in contrasts associated with breed (p < 0.05). Nutritional indices (PUFA/SFA, n-6/n-3 , atherogenic and thrombogenic, indices, and h/H ratio) showed no significant differences. Overall, the feeding system was primarily associated with antioxidant vitamins and SFA, while genetic background influenced MUFA and n-3 PUFA.