Constraints and potentials for the nutritional modulation of the fatty acid composition of ruminant meat

Abstract

The meat from ruminants can be a valuable dietary source of rumenic acid (c9,t11-CLA) and of n-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA). Nevertheless, commonly ruminant meats present a fairly low content of both c9,t11-CLA and n-3 LC-PUFA. Most of c9,t11-CLA in meat is derived from the delta-9 desaturation of t11-18:1 catalyzed by stearoyl-CoA desaturase (SCD) and deposited in triacylglycerides (TAG). Thus, optimizing c9,t11-CLA in meat implies: a high substrate supply, a high SCD activity, and a high intramuscular fat (IMF) deposition. High rumen t11-18:1 outflow requires high forage diets which down-regulate SCD activity and IMF deposition. Conversely, as most animals are finished with cereal rich concentrate diets, the SCD activity and IMF deposition are promoted but the rumen outflow of t11-18:1 frequently is replaced by t10-18:1 (t10-shift) which cannot be converted to CLA. Thus the occurrence of the rumen t10-shift is probably the main constraint to c9,t11-CLA enrichment in meat, as is reviewed in detail. The constrains to n-3 LC-PUFA enrichment of ruminant meat are mostly associated to the extensive rumen biohydrogenation of PUFA, the low elongation and desaturation of 18:3n-3 into n-3 LC-PUFA, and the capacity of muscle lipids to incorporate n-3 LC-PUFA. Considering the almost exclusive esterification of n-3 LC-PUFA in membrane phospholipids, the limits to n-3 LC-PUFA incorporation in muscle are discussed considering the amount of and type of available phospholipids as well as the possibility of its esterification in TAG.

Effect of feeding lambs with a tanniferous shrub (rockrose) and a vegetable oil blend on fatty acid composition of meat lipids

“…Due to its qualitative nature, gene expression data can only indicate possible changes in regulation of metabolic pathways. Moreover, postmortem SCD mRNA expression levels in muscle might not be the best predictor of the SCD products content in meat and of the sustained SCD activity during the finishing period, as was discussed by Bessa et al (2015). In the present experiment SCD mRNA expression levels apparently increased with Cistus level, although this was not confirmed by neither the MANOVA nor regression analysis with condensed tannins intake.…”

The effect of feeding system on slaughter-carcass characteristics, meat quality, and fatty acid composition of lambs

“…ALA is elongated and desaturated into longer-chain omega-3 FAs, such as C20:5n3 (EPA) and C22:6n-3 (DHA), and therefore, the availability of ALA is highly important (Bessa et al, 2015). In general terms, the effect of the feeding system on polyunsaturated FAs (PUFA) in tissues can be associated with the high amount of LA found in concentrate feed and of ALA in pasture ( Table 1).…”

Zaldi-haragiaren ezaugarritzea: konposizio kimikoa eta gantz-azidoen profila

“…tran-GA monoasegabeei dagokienez, hauen kopuru baxua ikusi da, eta azido elaidikoa (9t-18:1; % 0,0776) eta bakzenikoa (11t-18:1; % 0,0273) izan dira isomero nagusiak. Animalien ekoizpen-prozesuan jasotako elikadurak ezarriko du haragiaren trans-GAen konposizioa, eta hausnarkarien kasuan, 10t-edo 11t-isomeroak izan ohi dira gehienak [22]. Zaldi-eta ardi-haragiaren trans-konfigurazioko GAen, CLAen edo bestelako dienoen konparazioa 5. irudian erakusten da.…”