Fatty acid pro®les of yolk lipids of ®ve species of wild ducks (Anatidae) differing in dietary preference

The fatty acid compositions of yolk lipids of eggs collected in the wild from ®ve species of ducks (Anatidae) showing a range of dietary preferences, the king eider Somateria spectabilis, the lesser scaup Aythya af®nis, the mallard Anas platyrhynchos, the green-winged teal Anas crecca and the gadwall Anas streperi, are reported. For all ®ve species, the fatty acid pro®les conformed to a similar pattern, characterized by relatively balanced proportions (w/w) of arachidonic (6.7±9.1%) and docosahexaenoic (5.9±7.0%) acids in yolk phospholipid. This contrasts markedly with the yolk phospholipid of current commercially-reared ducks where the proportion of arachidonic acid can be 10 times greater than that of docosahexaenoic acid. It was most notable that the similarities in yolk fatty acid pro®les among the different species of wild ducks were achieved despite the considerable interspecies variation in dietary modes. It seems that, in this instance, genetic factors deriving from a common phylogeny may be more important than dietary differences in determining the fatty acid composition of yolk.