Production of Vitamin D-Fortified Eggs by Feeding of Vitamin D₂-Fortified Shiitake

Abstract

Laying hens were fed vitamin D₂-fortified shiitake (vitamin D₂ content 5000IU/g) diet on 0.1- 0.4% addition levels for 28 days. Transfer of vitamin D₂ in shiitake to egg yolk was confirmed by HPLC analysis. The vitamin D content (total amount of D₂ and D₃) in egg yolk increased steeply to the 7th day. After that it increased gradually until the 28 th day. The vitamin D content in egg yolk was 14.5IU/g on 0.4% addition at the 28 th day and was about 10-times that of control eggs, then the transfer ratio of vitamin D was 8.9%. The vitamin D content in egg yolk increased in proportion to the addition amount of fortified shiitake, therefore it may be possible to produce eggs of any vitamin D content. Vitamin D-fortified shiitake had no influence on performance of laying hens, eggshell quality and plasma calcium and phosphorus concentrations of laying hens.