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Research article2019Peer reviewedOpen access

Bioavailability of α-tocopherol stereoisomers in plasma and tissues of lambs fed different proportions of all-rac- α-tocopheryl acetate and RRR- α-tocopheryl acetate

Lashkari, Saman; Jensen, Soren Krogh; Bernes, Gun

Abstract

A ratio of 1.36:1 in relative bioactivity of RRR-alpha-tocopheryl acetate as a natural (Nat-alpha-T) source to all-rac-alpha-tocopheryl-acetate, as a synthetic (Syn-alpha-T) source, is generally accepted. This factor also largely reflects the difference in bioavailability. However, studies indicate that neither bioavailability of alpha-tocopherol stereoisomers nor relative bioavailability between them are constant, but are dose-dependent and differ between organs. However, no information is available about how different ratios between synthetic and natural alpha-tocopherol affect bioavailability of alpha-tocopherol stereoisomers. Thirty lambs were randomly assigned to diets supplied with additives containing 5 different Syn-alpha-T to Nat-alpha-T ratios, including 100: 0, 75: 25, 50: 50, 25: 75, and 0:100. The experiment lasted for 70 d after which the lambs were slaughtered. The amount of RRR-alpha-tocopherol generally increased in plasma and organs with increasing the proportion of Nat-alpha-T in the diet (P < 0.05). However, the relative bioavailability of RRR- and RRS-alpha-tocopherol in plasma, organs, and abdominal fat generally decreased with increasing the proportion of Nat-alpha-T in the diet (P < 0.05), whereas the other stereoisomers only showed minor changes with the exception of liver. However, a linear response was maintained between the ratio of stereoisomers in the feed and the ratio in plasma and organs. In conclusion, regardless of Syn-alpha-T to Nat-alpha-T ratio in the diets, amounts of alpha-tocopherol stereoisomers in plasma, brain, heart, lungs, and abdominal fat were in the following order: RRR > RRS, RSR, RSS > Sigma 2S.

Keywords

alpha-tocopherol stereoisomers; biodiscrimination; lambs

Published in

Journal of Animal Science
2019, Volume: 97, number: 3, pages: 1222-1233 Publisher: OXFORD UNIV PRESS INC

      SLU Authors

    • Bernes, Gun

      • Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences

    UKÄ Subject classification

    Animal and Dairy Science

    Publication identifier

    DOI: https://doi.org/10.1093/jas/skz011

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/99078