Milan Margetín

Time-dependent changes in milk fatty acid composition of ewes fed a winter ration supplemented with linseed or sunflower oils.

The effects of adding sunflower and linseed oils to a standard winter ration with a lower concentrate content on the milk fatty acid composition in lactating ewes were investigated. Eighteen dairy ewes randomly chosen from the ewe flock were divided into three groups: the first group was fed a winter ration, the second one a winter ration supplemented with sunflower oil, and the third a winter ration supplemented with linseed oil for a period of 12 days. In the treatment groups, the concentrate was partially replaced by 3.0 g/100 g sunflower or linseed oils. Milk samples were taken daily from morning milking for the analysis of fatty acid composition to determine their temporal daily variations. The responses to sunflower oil compared with linseed oil addition after the end of experi - ment were slightly higher for conjugated linoleic acid (CLA) ( P < 0.05), linoleic acid ( P < 0.001), trans-10 18:1 (P < 0.001), 6:0 to 16:0 ( P ≈ 0.05 - P < 0.001), whereas a higher content of α-linolenic acid (ALA) (3-fold) ( P < 0.001), oleic acid ( < 0.001), and 18:0 (P < 0.001) was found in milk after linseed oil addition. The responses to both oil additions were relatively sustainable with regard to CLA, trans-11 18:1 (vaccenic acid, VA), and ALA content after the last 6 days of supplementation. The winter ration supplementation with sunflower or linseed oil led to a 3-fold increase in CLA milk fat content (0.6-2.0 or 1.8 g/100 g fatty acid methyl esters (FAME), P < 0.001) and a 3-fold increase in VA milk fat content (1.2-3.8 or 4.1 g/100 g FAME, P < 0.001), however the content of trans-10 18:1 was 5-6-fold higher, compared with unsupplemented winter ration. Plant oil supplementation enhanced the total content of CLA, VA, ALA by 5.0 and 3.9 g/100 g FAME ( P < 0.001) for linseed and sunflower oil supplementation, and decreased the total content of 12:0, 14:0, and 16:0 by 9.3 and 5.8 g/100 g FAME ( P < 0.001) compared to winter diet, respectively.

Fatty Acids Profile of Intramuscular Fat in Light Lambs Traditionally and Artificially Reared

The quality of 40 carcasses of light lambs of the synthetic population of Slovak Dairy sheep from (a) artificial rearing (AR) and (b) traditional rearing (TR) was assessed on the basis of fatty acids profile of intramuscular fat (IMF). Lambs from AR in comparison with TR were of lower quality as assessed on the basis of fatty acids (FAs) profile. The content of conjugated linolic acid (CLA) in the fat of TR lambs was severalfold higher (0.749 vs. 0.193 g.100g-1 FAME, P<0.001) than in AR lambs. Similarly, the content of trans-vaccenic (TVA), a-linolenic (ALA), rumenic (RA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) was in TR lambs significantly higher (P<0.001) than in AR lambs (0.955 vs. 0.111; 0.715 vs. 0.251; 0.672 vs. 0.148; 0.352 vs. 0.061; 0.252 vs. 0.079 g.100g-1 FAME). In contrary, the content of linoleic acid (LA), the ratio of LA/ALA and n-6/n-3 in AR lambs was higher than in TR lambs (9.07 vs. 4.81 g.100 g-1 FAME; 39.11 vs. 6.80; 14.56 vs. 3.25, P<0.001). In TR lambs the content of n-3 PUFA and BCFA was significantly higher (P<0.001) than in AR lambs (2.08 vs. 0.84 and 1.95 vs. 0.45). The value of thrombogenic index was higher in AR lambs in comparison with TR lambs (1.44 vs. 1.31; P<0.05). Significant differences between FAs of IMF of ram lambs and ewe lambs were observed only in the case of arachidonic acid (P<0.05).

Fatty acids in intramuscular fat of Ile de France lambs in two different production systems

Abstract The fatty acid (FA) composition in the intramuscular fat (IMF) of the musculus longissimus dorsi (MLD) of Ile de France purebred lambs in two different production systems in Slovakia was evaluated using gas chromatography. In the first production system, lambs and ewes were assigned to pasture without access to concentrates (P). In the second system, lambs and ewes were confined indoors with hay/silage and access to concentrates (S). An analysis of variance with the following factors was employed: production system, sex, and production system–sex interactions. The proportions of arachidonic, eicosapentaeonic, docosapentaeonic, and docosahexaenoic FAs, i.e. long-chain polyunsaturated FA (PUFA), were significantly higher in P lambs (1.83, 0.82, 0.92, 0.29 g 100 g-1 FAME, respectively) than in S lambs (0.45, 0.14, 0.30, 0.09 g 100 g-1 FAME, respectively). The proportions of conjugated linoleic acid (CLA), n-6 PUFA, n-3 PUFA, and essential FA (linoleic and α-linolenic) were also significantly higher in P lambs (2.10, 8.50, 4.55, and 8.80 g 100 g-1 FAME, respectively) than in S lambs (0.65, 3.27, 1.50, and 3.64 g 100 g-1 FAME, respectively). The proportions of palmitic acid and myristic acid as important individual saturated FAs (SFA) were significantly higher in S lambs (28.51 and 8.30 g 100 g-1 FAME, respectively) than in P lambs (21.80 and 5.63 g 100 g-1 FAME, respectively). The proportion of all SFAs was also significantly higher in S lambs (57.87 g 100 g-1 FAME) than in P lambs (48.70 g 100 g-1 FAME). From a nutrition and human health point of view (i.e. higher proportions of PUFA, CLA, and essential FAs and lower proportions of SFAs), meat from P lambs was found to be more favourable and would be more highly recommended for consumption.