Abstract
White Leghorn hens fed diets contained 10% of beef tallow, lard, soybean or coconut oil, and were artificially inseminated with pooled semen. The fertile eggs from each group of hens were incubated until the chicks hatched to study the effects of egg yolk lipids components on the lipids of chicks. After removal of the yolk sac, the lipids were extracted from chicks and the yolk sacs including contents, and then the fatty acid compositions of chick lipids were compared with that of the unincubated egg yolk and of yolk sac lipids. Addition of various fat to the diet altered the fatty acid compositions of egg yolk lipids and the hatched chick lipids also affected by the maternal diet. Although the differences in fatty acid compositions of remained yolk sac lipids and unincubated egg yolk lipids were small, considerable differences were recognized betwe-en chick lipids and egg yolk lipids or yolk sac lipids in their fatty acid compositions. In general, chick lipids contained more C16:0 and total saturated acids and less C16:1 and C18:1 acids than unincubated egg yolk lipids in the total and neutral lipid fractions, but the chick phospholipids contained less C18:1 acid than the egg yolk and yolk sac phospholipids. A study was made on the positional distribution of fatty acids in triglycerides by means of pancreatic lipase hydrolysis technique. In the triglycerides isolated from the egg, chick and yolk sac lipids, there was a tendency for C16:0 and C18:0 acids to be esterified preferentially in the 1-and 3-positions, whereas there was a tendency for C18:1 and C18:2 acids to be esterified preferentially in the 2-position of glycerol in all four groups. Accordingly, it seemed that the positional distribution pattern of the fatty acids in triglycerides from chicks was virtually identical with those of the fatty acids in egg and yolk sac triglycerides.
