Effects of piscivory on the fatty acid profiles and antioxidants of avian yolk: studies on eggs of the gannet, skua, pelican and cormorant

Authors

  • Peter F. Surai,

    1. Avian Science Research Centre, Scottish Agricultural College, Auchincruive, Ayr KA6 5HW, U.K.
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  • Gary R. Bortolotti,

    1. Department of Biology, University of Saskatchewan, Saskatoon SK, Canada S7N 5E2
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  • Andrea L. Fidgett,

    1. Ornithology Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, U.K.
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  • Jonathan D. Blount,

    1. Ornithology Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, U.K.
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  • Brian K. Speake

    Corresponding author
    1. Avian Science Research Centre, Scottish Agricultural College, Auchincruive, Ayr KA6 5HW, U.K.
      All correspondence to: B. K. Speake, Avian Science Research Centre, Scottish Agricultural College, Auchincruive, Ayr KA6 5HW, U.K. E-mail: b.speake@au.sac.ac.uk
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All correspondence to: B. K. Speake, Avian Science Research Centre, Scottish Agricultural College, Auchincruive, Ayr KA6 5HW, U.K. E-mail: b.speake@au.sac.ac.uk

Abstract

Piscivorous birds consume diets which are rich in highly-polyunsaturated n-3 fatty acids; these play vital roles in embryonic development but are very susceptible to oxidative damage. The effects of such diets on the fatty acid composition and antioxidant content of the yolk were investigated in the northern gannet Morus bassanus, the great skua Catharacta skua, the American white pelican Pelecanus erythrorhynchos and the double-crested cormorant Phalacrocorax auritus. The phospholipid fraction of the eggs of these four species contained high proportions of the n-3 fatty acid, docosahexaenoic acid, which formed 7.5–11.3% (w/w) of the fatty acids of this fraction. The presence of eicosapentaenoic and docosapentaenoic acids also contributed to the total n-3 content of the phospholipid. The n-6 polyunsaturate, arachidonic acid, formed between 8% and 19% (w/w) of the phospholipid fatty acids. For the pelican and cormorant, this is consistent with the consumption of freshwater fishes in which arachidonic acid may be a significant acyl constituent. This finding is, however, more difficult to explain for the gannet and skua which largely consume marine fish with a low arachidonic acid content. The yolks of all four species contained relatively high concentrations of vitamin E (90.2–302.3 μg g−1 wet yolk) which was mainly present as α-tocopherol. The eggs of the pelican and cormorant were especially enriched in carotenoids (150.9 and 115.7 μg g−1 wet yolk, respectively).

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