CONTRIBUTION OF LONG CHAIN N-3 AND N-6 POLYUNSATURATED FATTY ACIDS FROM BEEF ACCORDING TO FEEDING REGIMEN

摘要

IntroductionHealth related concerns about beef are limited to its relatively high concentrations of hypercholesterolemic saturated fatty acids (SFA), low concentration of hypocholesterolemic polyunsaturated fatty acids (PUFA) and the presence of cholesterol. The recommended intake of n-6 fatty acids for humans is approximately 4 % of dietary energy with a minimum of 1.5% and the intake of n-3 fatty acids should be about 0.75% of dietary energy to avoid essential fatty acid deficiency. There is ample evidence that increased consumption of n-3 fatty acids protect against CHD and that excessive consumption of n-6 fatty acids at the expense of n-3 promotes CHD and other diseases. Analysis of n-3 PUFA intake, intake recommendations, and health claims are often limited to C18:3 (ALA), C20:5 (EPA) and C22:6 (DHA) and often omit C22:5 (DPA). DPA is an intermediate in the production of DHA from EPA and its contribution in beef lipids is higher than EPA and DHA. The functional and nutritional attributes of DPA are largely unknown, but some studies shows that DPA appears to be a primary end point for the synthesis of n-3 PUFA from ALA (Howe, Meyer, Record & Baghurst, 2005).The objective of this study was to evaluate the effects of animal diet, pasture only, pasture plus 0.7 and 1.0 % of live-weight grain supplementation and feedlot on the contribution of n-3 and n-6 PUFA of intramuscular lipids in Angus steers.