Effect of dietary fatty acids on incorporation of long chain polyunsaturated fatty acids and conjugated linoleic acid in lamb, beef and pork meat: a review

Inspired by the health conscious consumer, several studies in meat producing domesticated animals have been completed that have aimed at increasing the polyunsaturated fatty acid content, and in particular the n-3 or omega-3 long chain fatty acids, as well as the conjugated linoleic acid (CLA) content in intramuscular fat of beef, lamb and pork meat. Increasing the n-3 content in animal meats can be achieved by including fish oil/fish meal in the diet (i.e. rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), linseed (oil) and/or forages (i.e. rich in linolenic acid (LNA)). Diets rich in LNA result in an increased level of LNA, EPA and docosapentaenoic acid (DFA) in the meat, while in most cases no effect on intramuscular DHA level was observed. Increasing DHA contents in meat was mainly achieved when fish oil/fish meal was included in the animals diet. In most studies, an increased n-3 content in the intramuscular fat was accompanied with a decreased n-6 deposition, mainly due to a lower n-6 dietary supply between the treatments. This resulted in a more favourable n-6/n-3 ratio in the meat while the polyunsaturated fatty acid/saturated fatty acid (P/S) ratio was less affected. Attempts to increase the intramuscular c9t11CLA content was accomplished by feeding ruminants n-3 rich diets (linseed either or not in combination with grass (silage)), fish oil or high concentrate diets rich in linoleic acid (LA). The c9t11CLA content in beef and lamb meat varied between 0.2 and 1.0 g/100 g of total fatty acids and was not increased to a high extent by nutritional factors. In contrast, including CLA-oils consisting of several CLA isomers in the diet of monogastrics markedly increased the intramuscular CLA content. (C) 2003 Elsevier B.V. All rights reserved.