Selective deposition of trans-8- and cis-9-octadecenoates in egg and tissue lipids of the laying hen.

The disposition of trans-8-octadecenoate-8(9)-3H (8t-18:1-3H) was compared to cis-9-octadecenoate-10-14C (9c-18:.1-14C) in the major egg yolk neutral lipids and in organ lipids from the laying hen. trans-8-Octadecenoate was preferentially incorporated into only the phosphatidylethanolamines (PE), whereas discrimination against 8t-18:1-3H occurred in the phosphatidylcholines (PC), triglycerides (TG) and cholesteryl esters (CE). The a-acyl position of both PE and PC from the 2-acyl position of these phospholipids was found. Preferential incorporation of 9c-18:1-14C occurred at the combined 1- and 3-acyl positions and at the 2-acyl position of yolk TG. Tissue lipid analyses indicated that there was preferential deposition of 9c-18:1-14C into all organs. Individual liver lipid classes displayed the same relative order of discrimination against 8t-18:1-3H as did egg yolk lipids (CE greater than TG greater than PC greater than PE).