An apparent rachitogenic effect of excessive vitamin E intakes in the chick.

Three replicates (pens of 10 birds each) of a 2 X 2 factorial design experiment (25 and 10,000 IU vitamin E/kg diet on 25 and 500 IU vitamin D/kg diet) were utilized in order to assess effects of excessive intakes of vitamin E on calcium metabolism in the growing chick. A one-week equilibration period was followed by a two-week experimental period. Excessive vitamin E supplementation resulted in reduced calcium and phosphorus in blood plasma, in dry fat-free bone, and in bone ash, calcium, and phosphorus. Inadequate vitamin D supplementation reduced total feed consumption, terminal body weight, plasma calcium, dry fat-free-bone, bone ash, bone calcium, and bone phosphorus. Significant vitamin E X vitamin D interactions were noted for plasma calcium, dry bone, and bone ash, excessive vitamin E apparently interfering with vitamin D utilization.