Yolk lipids of developing atherosclerosis susceptible White Carneau and atherosclerosis resistant Show Racer pigeon embryos.

The lipid composition of yolks of developing embryonic atherosclerosis-susceptible White Carneau (WC) and -resistant Show Racer (SR) pigeons was analyzed to determine whether embryonic nutrition might be a factor in the difference in susceptibility to aortic atherosclerosis. The yolks of 1-day and 18-day old embryos were analyzed, and the amounts of phospholipid, sterol, non-esterified fatty acid, triglyceride, cholesteryl ester, and hydrocarbon were determined. On the first day of development in both breeds, triglycerides composed 80% of the total lipid content of the yolk; phospholipids, cholesteryl ester, sterols and non-esterified fatty acids comprised the rest. There was no difference between breeds in the amount of lipid in each class or in the total lipid. Therefore, the initial lipid diet of these embryos is not a factor in development of the disease. Examination of the yolk just prior to hatching, revealed that in both breeds there was a significant decrease in total yolk lipids, but unequal utilization of lipid constitutents between breeds. Significantly higher amounts of phospholipids remained in the yolk of the WC pigeons. During embryogenesis, the SR pigeons consumed significantly more of each lipid than the atherosclerosis-susceptible breed. This may indicate that there is a difference between the two breeds in lipid metabolism.