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.
Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C&E Trail, Lacombe, Alberta T4L 1W1, Canada.
C
C
Mapiye
M E R
ME
Dugan
M
M
Juárez
J A
JA
Basarab
V S
VS
Baron
T
T
Turner
X
X
Yang
N
N
Aldai
J L
JL
Aalhus
D000818:Animals; D002417:Cattle; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements; D005227:Fatty Acids / Q000032:analysis; D001467:Hordeum; D008041:Linoleic Acids / Q000032:analysis*; D044243:Linoleic Acids, Conjugated / Q000032:analysis*; D008297:Male; D008460:Meat / Q000032:analysis*; D050151:Subcutaneous Fat / Q000187:drug effects; D044242:Trans Fatty Acids / Q000032:analysis; D024502:alpha-Tocopherol / Q000494:pharmacology*
D005227:Fatty Acids; D008041:Linoleic Acids; D044243:Linoleic Acids, Conjugated; D044242:Trans Fatty Acids; D024502:alpha-Tocopherol