Content of carotenoids and retinol in hen's eggs.

The determination of eight carotenoids (alpha-, beta-carotene, cryptoxanthene, luteine, zeaxanthene, canthaxanthene, lycopine, beta-apo-carotinic acid ethyl ester) and vitamin A was carried out by reversed phase HPLC. The obtained results from eight egg types [six commercially available types: summer (FS) and winter (FW) free range eggs, eggs from floor system (BoH), four-grain eggs (BV), eggs from battery system (BTT), docosahexaenoic acid eggs (DHA), and two egg types from a feeding trial by BASF: B4 with fish oil, B11 with linseed oil] showed clear differences in their concentration of vitamin A and carotenoids. Highest concentrations of vitamin A were found in the eggs from the free range system. The other eggs showed lower vitamin A concentrations with a homogenous distribution. Similar trends were observed for the concentrations of carotenoids. Highest concentrations of vitamin A active carotenoids were observed for summer eggs from the free range system. The most important non vitamin A specific carotenoids were luteine and zeaxanthene. Both isomers were again found in highest concentrations in summer eggs from the free range system. Luteine concentration in the eggs from the feeding trial (B4, B11) was only 10% of the concentrations in eggs from the free range system. No zeaxanthene could be detected in these eggs. In the latter eggs, C30-esters and canthaxanthene could be detected, which were added to the feed. Lycopine traces could be detected in DHA-eggs only. As expected, the eggs showed only traces of vitamin A active carotenoids increasing the amount of retinol equivalents by approximately 1.2%. The highest contribution to the daily carotenoid supply origins from the non vitamin A active carotenoids luteine and zeaxanthene with approximately 310 mu g.