[Incorporation and mobilization of vitamin A in laying hens]

216 laying hybrids were given diets with 1500, 3000 or 6000 IU vitamin A kg-1 between their 21st and 64th week of age. The ration did not contain any vitamin A between the 5th and 16th as well as the 25th and 28th week. The control animals were fed a diet with 6000 IU kg-1. Feed consumption, laying performance, egg weight, feed efficiency, mortality and the vitamin A content in egg yolk and liver depend on the vitamin A supply. 4-week depletion took an adverse effect on feed intake and laying performance. It was not possible to detect vitamin A in the egg yolk after 4 weeks and in the liver after 16 weeks of depletion.