The nutritional and health value of beef lipids - fatty acid composition in grass-fed and grain-fed beef

Interest in meat fatty acid (FA) composition stems mainly from the need to find ways to produce healthier meat with a suitable ratio of polyunsaturated (PUFA) to saturated fatty acids (SFA) and a favourable balance between n-6 and n-3 PUFA. Studies of grass feeding versus grain feeding cattle have been conducted in different regions throughout the world and suggest that grass-based diets can significantly improve the fatty acid (FA) composition of beef. Compared with grain diets, grass diets contribute to a lower total fat content and more favourable SFA composition i.e. higher proportion of low density lipoprotein (LDL) and cholesterol-neutral stearic acid (C18:0). Feeding fresh grass compared to concentrates results in higher levels of n-3 PUFA in muscle lipids and a more favourable n-6/n-3 PUFA ratio that is within the nutritional recommendations for the human diet.

Alpha Linolenic Acid Variability Influences the Positive Association between %Eicosapentaenoic Acid and % Arachidonic Acid in Chicken Lipids

Body concentrations of Arachidonic Acid (AA, 20:4 n6) and Eicosapentaenoic Acid (EPA, 20:5 n 3) are influenced by diet. Previously, we reported that the concentration range of AA and EPA might explain that %AA and %EPA are positively associated, and that variability of OA (18:1 c9) influences this association. We now investigate whether also the range of ALA (18:3 n3) might influence the association between %AA and %EPA, using data from a diet trial in chickens. A broadening (narrowing) of ALA-variability made the %AA vs. %EPA scatterplot improve (be poorer), as observed both when calculating percentages of all fatty acids, and when using ALA, AA, and EPA only in the denominator. Thus, the positive association between relative amounts of AA and EPA in breast muscle lipids of chickens is influenced by ALA variability. We raise the question of whether differences in concentration ranges between the many types of fatty acids (possibly acting via skewness) might serve as an evolutionary mechanism to ensure that percentages of fatty acids will be positively or negatively associated: a Distribution Dependent Regulation.

Development of Technology for Producing Beef With A Modified Fatty Acid Composition

The article presents the results of an assessment of the effect of making oil (Echium vulgare) rich in 18: 4 n-3 PUFAs on the fatty acid composition and qualitative indicators of beef. The introduction of this oil suggested an increase in the deposition of C18: 3n-3 and the long chain fatty acids C20 and C22, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) in muscle lipids. It was found that the introduction of echium oil or linseed oil in the diet of cattle contributed to the improvement of the profile of long-chain C20 fatty acids in beef, but had a negligible effect on its quality indicators

Visceral oil from farmed Sparus aurata, Dicentrarchus labrax and Diplodus puntazzo as a source of ω-3 PUFA

Crude oils recovered from the viscera of conventionally and organically farmed gilthead sea bream (Sparus aurata), European seabass (Dicentrarchus labrax) and sharpsnout sea bream (Diplodus puntazzo) were characterised. Triacylglycerols (TAG) and phospholipids (PL) were the major lipid classes. Visceral oils contained high levels of n-3 polyunsaturated fatty acids (PUFA), in particular docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The DHA/EPA ratios (range 1.66–2.46) were higher in organically farmed fish. Total PUFA and n-3 fatty acid levels varied according to both species and rearing system, and were higher in the conventionally farmed sparids. The ratios of n-3 to n-6 PUFA (1.42–2.19) were comparable to the values reported for muscle lipids, while the PUFA/SFA ratios (1.07–1.33) exceeded the recommended value. Visceral oils exhibited good oxidative stability, as judged by monitoring lipid oxidation products during storage at 63°C. These data indicate that the viscera of all three species may represent a good source for the production of omega-3 rich oils.