Availability of cell wall-fractured yeast, Phaffia rhodozyma, containing high concentration of astaxanthin for egg yolk pigmentation.

Two experiments were conducted to evaluate the egg yolk-pigmenting potential of Phaffia rhodozyma, a high astaxanthin (Ax)-containing yeast with or without cell wall treatment in comparison with that of paprika, a naturally occurring pigment source in laying hens for 2 or 3 weeks. Non-treated Phaffia yeasts, cell wall-fractured yeasts and extracted-Ax were supplemented to provide up to 3ppm Ax in diets. Paprika was included in diets to provide 2.5 and 5ppm carotenoids. Roche color fan score and a* value on Chroma Meter analysis increased with an increase of the dietary Ax concentration. In the yolk pigmentation, Ax in the fractured yeasts was as potent as extracted-Ax and 3 fold higher than the non-treated yeasts. These results show that mechanical fracturing of the cell wall of Phaffia yeasts intensifies the pigmentation efficiency of Ax by 3 fold. Accumulation of Ax in egg yolks increased by the fracturing of yeasts. Roche color fan score and a* value increased with an increase of paprika from 0 to 5ppm in diets. In the yolk-pigmenting efficiency as judged by color fan score and a* value, Ax in the fractured yeasts was 1.5 to 2 fold as potent as paprika on the carotenoid concentration basis. Dietary Ax was deposited in the yolk with the efficiency of 7.1 and 11.4% in cases that Ax in the fractured yeasts was included at 1.25 and 2.5ppm in diets, respectively. These results show that the cell wall-fractured Phaffia yeast containing high concentration of Ax can be an useful source for the egg yolk pigmentation.