C18 TRANS MONOUNSATURATED FATTY-ACID IN THE DIET OF THE HEN AND ITS ACCUMULATION IN YOLK AND EMBRYO TISSUE

The presence of trans unsaturated fatty acid isomers in the diet of th e hen is readily translated into significant accumulations in the yolk lipid. In turn, the processes of yolk lipid assimilation ensure subse quent uptake into the yolk sac membrane and distribution to the develo ping embryonic tissues. In particular the trans isomers become associa ted with newly synthesised cholesteryl esters originating from the yol k sac membrane which are an essential component for yolk lipid transfe r and uptake by the embryo. Within the liver. the accumulation of lipi d, almost wholly as cholesteryl esters, leads to the trans isomer frac tion becoming a major component of the tissue. Possible metabolic cons equences arising from the transfer and subsequent substantial tissue a ccumulation of trans unsaturated components are outlined. In the light of definitive evidence from other animal species it is suggested from the present investigations that the presence of trans unsaturated iso mers in the diets of breeder hens should be reduced to a minimum.