Efeitos de dietas sobre a composição em ácidos graxos de novilhas terminadas em confinamento

The effects of diet on Longissimus muscle fatty acid composition was determined using 24 crossbred heifers of Simmental vs. Nelore and Limousin vs. Nelore. The experimental diets were: 1) corn and yeast (CY); 2) corn, cottonseed meal + meat and bones meal (CMB); 3) cassava hull and yeast (CHY); 4) cassava hull, cottonseed meal + meat and bones meal (CHMB). Feeding CHMB diets resulted in lower lipid and higher cholesterol contents (P<0.05) for both crosses. Most of the identified fatty acids were monounsaturated, and the highest percentage was found to oleic acid (C18:1w9), with values ranging from 32.54 to 46.42%. Among the saturated fatty acids the palmitic acid (C16:0) showed the highest percentage, with its contents ranging between 19.40 and 32.44%. The highest polyunsaturated/saturated fatty acid ratio was of 0.30, and the lowest was of 0.08. Feeding CY diets resulted in lower cholesterol and higher polyunsaturated fatty acid contents of the Longissimus muscle.Efeitos de dietas sobre a composição em ácidos graxos no músculo Longissimus foram determinados, usando 24 novilhas mestiças Simmental vs. Nelore e Limousin vs. Nelore. As dietas experimentais foram: 1) milho e levedura (ML); 2) milho, farelo de algodão + farinha de carne e ossos (MiACO); 3) casca de mandioca e levedura (ML); 4) casca de mandioca, farelo de algodão + farinha de carne e ossos (MaACO). Dietas com a ração MaACO resultaram em carne com baixo teor de lipídios e alto teor de colesterol (P