Distribution of N-acetylneuraminic acid and sialylglycan in eggs of the Silky fowl.

1. The distribution of sialic acid in the eggs of original Silky fowl was investigated. The sialic acid contents of the yolk, albumen and the chalaza of a single egg were 205.2, 11.96 and 0.83 mg, respectively. 2. The sialic acid content of the yolk of Silky eggs was 11.5-fold higher than that of a conventional domestic fowl yolk. 3. Sialic acid isolated from Silky yolk was entirely N-acetylneuraminic acid (NeuAc). No N-glycolylneuraminic acid or O-acetyl containing sialic acid was observed. 4. The structure of the major sialylglycan in Silky egg yolk was determined to be a disialyl-biantennary chain in which the NeuAc residues were alpha2-6 linked to glucose. No alpha2-3 linkage was observed. 5. Thus, the Silky fowl's egg provides an excellent source of NeuAc and sialylglycan.