Effects of different hybrids, strains and age of laying hens on the cholesterol content of the table egg.

Three experiments were carried out to investigate the effects of age, moulting and strain of hens on the weight, total cholesterol content (TCh) and cholesterol concentration (CCh) of egg yolk. Only slight differences were found in the TCh and CCh of eggs between white and brown egg layer hybrids (Shaver SC 288 vs. Shaver SC 579) of the same age. On the other hand, significant differences (p < 0.05) were found in yolk CCh and TCh of both hybrids during the production period. The change in yolk CCh was periodical: it decreased in both hybrids until 45 weeks of age, then it increased, reaching a plateau between weeks 51 and 54, and declined again at the end of production. TCh, however, increased until 51 (Shaver SC 579) or 54 (Shaver SC 288) weeks of age, which could be attributed to the steady increase in yolk weight throughout the production period. In the eggs of Tetra-SL hens yolk weight, yolk CCh and TCh were slightly higher after moulting (at 108 weeks of age) than in the first production period (at 48 weeks of age), but the differences were not significant (p > 0.05). Significant inter-strain differences (p < 0.05) were found, however, in the yolk parameters measured. The highest values were found in the eggs of New Hampshire hens, as compared to the traditional Hungarian breeds. The eggs of traditional pure-bred hens contained a substantially higher amount of cholesterol than those produced by the hybrids.