N-3 fatty acids and conjugated linoleic acids of longissimus muscle in beef cattle

Abstract

The objective of the experiment with cattle was to produce high quality beef under different feeding conditions and to increase the concentration of essential fatty acids in muscle. In total 10 German Simmental (GS) bulls and 9 German Holstein (GH) steers were kept either on pasture (grass feeding) or in stable (concentrate feeding). Despite biohydrogenation in the rumen, linolenic acid (C18:3n-3) contained in grass was absorbed and deposited into the lipids of muscle. This led to a significantly (p ≤ 0.05) higher content of n-3 fatty acids in the muscle lipids of grazing cattle. The relative amount of total n-3 fatty acids increased from 1.4 g/100 g fatty acid methyl ester (%FAME) in the intensively fed Simmental bulls to 5.5 %FAME in grass fed cattle. The n-6/n-3 ratio of pasture grazing GS bulls was 1.3 in contrast to 13.7 of the animals kept in the byre. The total n-3 fatty acid concentration in beef muscle increased from 24.6 mg (concentrate) to 108.6 mg/100 g wet weight (grazing). In GH steers the total n-3 fatty acid concentration was significantly (p ≤ 0.05) increased up to 86.3 mg/100 g wet weight in pasture grazing steers compared to 28.8 mg/100 g wet weight in animals fed the concentrate. The relative content (%FAME) of CLAcis-9, trans-11 (0.6 vs 0.56 %FAME in GS; 0.55 vs 0.52 %FAME in GH) in muscle was not significantly increased by grazing on pasture in comparison to concentrate feeding neither in GS bulls nor in GH steers, respectively.