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Effect of grass vs. concentrate feeding on the fatty acid profile of different fat depots in lambs

2005; Wiley; Volume: 107; Issue: 10 Linguagem: Inglês

10.1002/ejlt.200501141

1438-9312

Karin Nuernberg, Gerd Nuernberg, K. Ender, Dirk Dannenberger, Wiebke Schabbel, S. Grumbach, W. Zupp, Hans Steinhart,

Animal Nutrition and Physiology

The aim of this study was to produce high-quality meat from lambs under different feeding conditions, as measured by the accumulation of n-3 fatty acids and conjugated linoleic acids (CLA) in muscle and subcutaneous fat. In total, 13 male crossbred lambs (Black Head×Gotland), each at 24 kg live weight, were divided into two feeding groups. Lambs were kept either on pasture (pasture grazing, n = 6) or in the stable (concentrate feeding, n = 7). The linolenic acid (C18:3n-3) contained in the grass was absorbed and deposited into the different lipid classes of muscle and subcutaneous fat. The proportion of total n-3 fatty acids in the different lipids of grazing lambs was significantly (p = 0.05) higher compared to that in concentrate-fed lambs. The n-6/n-3 ratio (mean ± SEM) in muscle of grazing lambs was 1.2 ± 0.09 in contrast to 2.3 ± 0.09 (p = 0.05) of the animals kept in the stable. In subcutaneous fat, this ratio was 0.9 ± 0.2 in lambs kept on pasture versus 3.5 ± 0.2 (p = 0.05) after indoor keeping. The relative concentration of C18:1trans-11 in total muscle lipids, phospholipids, triacylglycerols and subcutaneous fat was significantly increased by grass feeding compared to concentrate feeding. Significant influences of feeding were shown for saturated fatty acids. In concentrate-fed lambs, a lower content of saturated fatty acids was detected. The proportion of CLAcis-9,trans-11 (1.9 ± 0.2% vs. 1.1 ± 0.1% in muscle, 2.5 ± 0.2% vs. 1.4 ± 0.2% in subcutaneous fat, 0.7 ± 0.04% vs. 0.4 ± 0.04% in phospholipids) in lambs was significantly (p = 0.05) higher after grazing than after concentrate feeding, respectively.