Trans-18:1 and conjugated linoleic acid profiles after the inclusion of buffer, sodium sesquicarbonate, in the concentrate of finishing steers

Trans-10 18:1 in ruminant meats: A review

Trans (t) fatty acids (TFA) from partially hydrogenated vegetable oils (i.e., industrial trans) have been phased out of foods in many countries due to their promotion of cardiovascular disease. This leaves ruminant-derived foods as the main source of TFA. Unlike industrial TFA where catalytic hydrogenation yields a broad distribution of isomers, ruminant TFA are enzymatically derived and can result in enrichment of specific isomers. Comparisons between industrial and ruminant TFA have often exonerated ruminant TFA due to their lack or at times positive effects on health. At extremes, however, ruminant-sourced foods can have either high levels of t10- or t11-18:1, and when considering enriched sources, t10-18:1 has properties similar to industrial TFA, whereas t11-18:1 can be converted to an isomer of conjugated linoleic acid (cis(c)9,t11-conjugated linoleic acid), both of which have potential positive health effects. Increased t10-18:1 in meat-producing ruminants has not been associated with negative effects on live animal production or meat quality. As such, reducing t10-18:1 has not been of immediate concern to ruminant meat producers, as there have been no economic consequences for its enrichment; nevertheless at high levels, it can compromise the nutritional quality of beef and lamb. In anticipation that regulations regarding TFA may focus more on t10-18:1 in beef and lamb, the present review will cover its production, analysis, biological effects, strategies for manipulation, and regulatory policy.

Red blood cells are superior to plasma for predicting subcutaneous trans fatty acid composition in beef heifers

The trans (t)-18:1 content in beef has become more of interest as partially hydrogenated vegetable oils are removed from foods. Predicting t-18:1 early in the feeding period would be useful if limitations are put on t-18:1 in beef. To determine which blood component is better related to backfat, proportions of t10-18:1 and t11-18:1 (vaccenic acid) were measured in heifer red blood cells (RBC) and plasma (N = 14) after 0, 28, 56, and 76 d on a barley-grain-based diet, and correlated with post-slaughter subcutaneous fat (SCF). Total t-18:1 declined in both RBC and plasma during late finishing (P < 0.05). At 28 d, t11-18:1 decreased and t10-18:1 increased in RBC and plasma (P < 0.05). By 76 d, t10-18:1 declined to 0 d levels. RBC and plasma t-18:1 compositions were highly correlated (t10-18:1, r ≥ 0.7, P ≤ 0.02; t11-18:1, r ≥ 0.51, P ≤ 0.06). Correlations with post-slaughter backfat were, however, consistently greater for RBC compared with plasma. The use of RBC t-18:1 composition may, therefore, be superior to plasma for predicting t-18:1 in SCF, and the length of finishing could be useful for manipulating t-18:1 in beef. The time required for changes in t18:1 in RBC to reflect in changes in SCF still, however, needs to be determined to establish optimal durations for beneficial modification.

Characterization of the fatty acid composition of lamb commercially available in northern Spain: Emphasis on the trans-18:1 and CLA content and profile

A survey of commercially available lamb meat was performed in northern Spain in order to evaluate their fatty acid (FA) composition with emphasis on trans fatty acid (TFA) and conjugated linoleic acid (CLA) isomers. Samples were collected in spring (n=24) and winter (n=24) of 2013, and were obtained in about equal numbers from grocery stores and butcher-shops. Subcutaneous fat, known to be a sensitive indicator of TFA content in ruminants, was analyzed by GC-FID. In general, very few differences were observed between collection periods and type of stores because of the high variability within the groups that was believed to be associated with differences in genetics and feeding strategies. However, the 10t/11t ratio of all samples showed two clearly identifiable groups irrespective of the source: 1) when 10t/11t was >1, 10t-shifted samples; 2) when 10t/11t was ≤1, non-shifted samples where 11t-18:1 was the predominant isomer. These two groups were clearly identified and associated with distinct FAs using principal component analysis.

Características de carcaça de cordeiras Pantaneiras abatidas com diferentes espessuras de gordura subcutânea

Foram utilizadas 24 cordeiras do grupo genético Pantaneiro, abatidas com 2,0; 3,0 e 4,0 mm de espessura de gordura, avaliadas por ultrassonografia no Longissimus dorsi. Avaliaram-se características quantitativas de carcaça, do lombo e índice de musculosidade da perna. As cordeiras receberam ração completa misturada calculada para ganho de peso diário de 0,300 kg. Foram realizadas avaliações por ultrassonografia (entre a 12ª e a 13ª costela) e pesagens a cada 14 dias, sendo que os abates ocorriam à medida que as cordeiras atingiam a espessura de gordura pré-determinada: 2,0; 3,0 e 4,0mm. Não houve efeito para rendimento verdadeiro da carcaça, rendimento comercial da carcaça e índice de compacidade da perna. Foi observado maior rendimento do lombo para cordeiras abatidas com 4,0mm de espessura de gordura subcutânea. As espessuras de gordura subcutânea não influenciaram a área de olho de lombo, porém animais com 4,0 mm apresentaram maiores medidas. Foram observadas diferenças nas proporções de músculo, osso e gordura da perna entre as espessuras de gordura subcutânea avaliadas. A musculosidade da perna não foi influenciada com o aumento da espessura da gordura subcutânea. Com base neste estudo e também com as exigências do mercado consumidor, recomenda-se o abate de animais com aproximadamente 3,00 mm de gordura.

Triticale dried distillers' grain increases alpha-linolenic acid in subcutaneous fat of beef cattle fed oilseeds

This study investigated the effect of triticale dried distillers' grain with solubles (DDGS), flax (FS) and sunflower (SS) seed on growth and the fatty acid profile of subcutaneous (SQ) fat in individually housed steers (n = 15 per diet) fed ad libitum (DM basis); (1) control (CON) 90% barley grain + 10% barley silage; or substitution of barley grain for: (2) 30% DDGS; (3) 10% FS; (4) 30% DDGS + 8.5% FS; (5) 10% SS and (6) 30% DDGS + 8.5% SS. Oilseeds in the combination diets were reduced to maintain diet lipid levels below 9% DM and to determine if favorable changes in the fatty acid profile could be maintained or enhanced at reduced levels of oilseed. Plasma and SQ fat biopsies were collected at 0, 6, and 12 weeks. Inclusion of DDGS decreased (P < 0.05) average daily gain, feed conversion and backfat thickness. Feeding FS increased (P < 0.05) plasma ALA compared to CON and SS and consistently increased (P < 0.01) ALA and non-conjugated and non-methylene interrupted dienes (NCD), whereas SS tended to decrease ALA in fat. Inclusion of DDGS with FS further increased (P < 0.02) ALA and decreased (P < 0.05) NCD and 18:1-t10 in fat. The fact that the levels of n-3 fatty acids in SQ fat from steers fed DDGS + FS were higher than those obtained with FS alone, has obvious benefits to the practical cost of favorably manipulating fatty acid profiles in beef.

Influence of α-tocopherol supplementation on trans-18:1 and conjugated linoleic acid profiles in beef from steers fed a barley-based diet

The current study was conducted to determine the effect of different α-tocopherol (vitamin E) inclusion levels on trans(t)-18:1 and conjugated linoleic acid (CLA) profiles in subcutaneous and intramuscular fat of steers fed a barley-based diet. Fifty-six feedlot steers were offered a barley-based finisher diet (73% steam rolled barley, 22% barley silage and 5% supplement as-fed basis) with four levels of supplementary dl-α-tocopheryl acetate (340, 690, 1040 or 1740 IU/steer per day) for 120 days. Adding vitamin E to the diet had little effect on the overall fatty acid composition of intramuscular fat. The proportion of individual and total t,t- and cis(c),t-CLA, n-3 fatty acids, total polyunsaturated fatty acids (PUFA), mono-unsaturated fatty acids and saturated fatty acids to PUFA ratio in subcutaneous fat were not influenced (P > 0.05) by dietary vitamin E supplementation. Increasing levels of vitamin E led to linear reductions in t6-/t7-/t8-18:1 and t10-18:1 (P < 0.05), and linear increase in t11-/t10-18:1 ratio (P < 0.05) in subcutaneous fat. The content of 20:3n-6 and total n-6 in subcutaneous fat decreased (P < 0.05) linearly with increasing amounts of vitamin E. The subcutaneous fat n-6:n-3 ratio showed a quadratic (P < 0.05) response to vitamin E. In conclusion, although vitamin E supplementation has some potential to reduce t10-18:1 formation and increase t11-/t10-18:1 ratio in subcutaneous fat of cattle fed barley-based diets, the changes in the present study were limited and may not have been sufficient to impact on human health.

Review:Trans-forming beef to provide healthier fatty acid profiles

Dugan, M. E. R., Aldai, N., Aalhus, J. L., Rolland, D. C. and Kramer, J. K. G. 2011. Review: Trans- forming beef to provide healthier fatty acid profiles. Can. J. Anim. Sci. 91: 545–556.Trans fatty acids are found naturally in foods, particularly in those derived from ruminant animals, such as beef and dairy cattle. Over the past few decades, human consumption of trans fatty acids has increased, but this has been mainly from products containing partially hydrogenated vegetable oils. The correlation of trans fatty acid consumption with diseases such as coronary heart disease has been cause for concern, and led to recommendations to reduce their consumption. Trans fatty acids, however, have differing effects on human health. Therefore, in foods produced from ruminant animals, it is important to know their trans fatty acid composition, and how to enrich or deplete fatty acids that have positive or negative health effects. This review will cover the analysis of trans fatty acids in beef, their origin, how to manipulate their concentrations, and give a brief overview of their health effects.