Dietary effects on muscle fatty acid composition of finished heifers

Abstract

-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 (C18:1ω9), 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.Index terms: muscles, rations, unsaturated fatty acids, saturated fatty acids. Efeitos de dietas sobre a composição em ácidos graxos de novilhas terminadas em confinamentoResumo -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<0,05) em ambas as raças. A maioria dos ácidos graxos identificados foram monoinsaturados, com maior porcentagem para o ácido oléico (C18:1ω9), com valores variando de 32,54 a 46,42%. Entre os ácidos graxos saturados, o palmítico (C16:0) mostrou a maior porcentagem, variando de 19,40 a 32,44%. A maior razão ácido graxo poliinsaturado/saturado foi de 0,30 (ML) e a menor de 0,08 (MiACO). A carne de novilhas alimentadas com a dieta ML apresentou menor teor de colesterol e maior teor de ácidos graxos poliinsaturados.Termos para indexação: músculos, ração, ácidos graxos insaturados, ácidos graxos saturados.

The influence of dietary soyabean and linseed on the chemical composition and fatty acid profile of the <i>Longissimus</i> muscle of feedlot-finished bulls

“…Similar results were reported by Silva et al (2002) in crossbred heifers (Limousin vs Nellore and Simmenthal vs Nellore), approximately 18 months old, with an average moisture level of 74.6%. Higher levels were obtained by Abularach et al (1998) in Nellore young bulls aged 23-29 months, feedlot-fi nished, with an average moisture level of 75.6%.…”

“…Lower results were reported by Silva et al (2002) and Prado et al (2003), who obtained average results of 44.26 and 44.58%, respectively.…”

“…Higher levels were obtained by Prado et al (2003), with an average value of 46.00%, but lower value were reported by Silva et al (2002), who obtained an average result of 42.88%. The average observed value for PUFA in this experiment was 7.60%.…”

“…Lower results were found by Silva et al (2002), with an average value of 5.69%. Prado et al (2003) observed higher levels, with an average value of 9.14%.…”

“…Lower ratios were observed by Silva et al (2002) and Prado et al (2003) with average values of 1.27 and 2.78, respectively. In general, the n-6:n-3 ratio is infl uenced by the fatty acid composition of animal diets.…”