FUCOXANTHIN METABOLITES IN EGG-YOLKS OF LAYING HENS

Feeding experiments were conducted with White leghorn laying hens fed a carotenoid depleted control diet (containing some zeaxanthin and lut ein) or this diet supplemented with 15% seaweed meal of established ca rotenoid composition. Egg yolk colour was estimated by use of a Roche Yolk Colour Fan and by detailed quantitative and qualitative carotenoi d analysis of individual eggs of three laying hens during 4 weeks. Ide ntification of the carotenoids included HPLC, VIS, MS, H-1 NMR data an d partial synthesis. The results confirmed that fucoxanthin, the major carotenoid in seaweed meal, is not transferred to the yolk. However, fucoxanthin gave rise to the metabolites fucoxanthinol, fucoxanthinol 3'-sulphate and paracentrone, that are ascribed to enzymatic modificat ions occurring in the hens. The difuranoid auroxanthin encountered in the egg yolk was ascribed to violaxanthin and/or its furanoid derivati ves present in the seaweed meal. Colour of individual yolks varied con siderably. The pigmentation level is discussed. (C) 1998 Elsevier Scie nce Inc. All rights reserved.