title: Effects of vitamin E and flaxseed on rumen-derived fatty acid intermediates in beef intramuscular fat.
abstract: To elucidate the effects of dietary vitamin E with or without flaxseed on beef fatty acid composition, 80 feedlot steers were fed 4 diets: Control-E (451 IU dl-α-tocopheryl acetate/head/day), Control+E (1051 IU dl-α-tocopheryl acetate/head/day), Flax-E (10% ground) and Flax+E. Vitamin E had no effect on animal growth or carcass weight (p>0.05), while flaxseed-fed steers had greater average daily gain (p=0.007), final live weight (p=0.005) and heavier carcasses (p=0.012). Feeding flaxseed increased the total n-3 fatty acid content of beef and this response was further accentuated by the inclusion of high levels of vitamin E in the diet. Feeding flax increased levels of some 18:3n-3 partial hydrogenation products including c15- and t13/14-18:1 and several 18:2 isomers (p<0.001) but decreased t10-18:1 (p<0.001). Vitamin E enhanced intramuscular levels of 18:3n-3 and its biohydrogenation products leading to greater accumulations of total n-3 fatty acids in lean ground beef. The consequences of increasing the concentrations of partially hydrogenated products on human health have yet to be investigated.
authors.affiliation: Agriculture and Agri-Food Canada, Lacombe Research Centre, 6000 C & E Trail, Lacombe, AB, Canada T4L 1W1.
authors.forename: Manuel
authors.initials: M
authors.lastname: Juárez
authors.forename: Michael E R
authors.initials: ME
authors.lastname: Dugan
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Aalhus
authors.forename: Noelia
authors.initials: N
authors.lastname: Aldai
authors.forename: John A
authors.initials: JA
authors.lastname: Basarab
authors.forename: Vern S
authors.initials: VS
authors.lastname: Baron
authors.forename: Tim A
authors.initials: TA
authors.lastname: McAllister
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000254:growth & development*; D004032:Diet / Q000662:veterinary*; D004041:Dietary Fats / Q000032:analysis; D015525:Fatty Acids, Omega-3 / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D005285:Fermentation; D019597:Flax / Q000737:chemistry* / Q000378:metabolism; D006865:Hydrogenation; D050152:Intra-Abdominal Fat / Q000737:chemistry*; D007536:Isomerism; D008055:Lipids / Q000032:analysis; D008297:Male; D008460:Meat / Q000032:analysis; D018482:Muscle, Skeletal / Q000737:chemistry*; D012417:Rumen / Q000382:microbiology; D012639:Seeds / Q000737:chemistry / Q000378:metabolism; D044242:Trans Fatty Acids / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D014810:Vitamin E / Q000008:administration & dosage*
chemical_list: D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D008055:Lipids; D044242:Trans Fatty Acids; D014810:Vitamin E