1. Divisions of Nutrition and Reproduction, Royal Veterinary and Agricultural University, Frederiksberg DK-1870, Denmark
2. Leo Pharmaceutical Products, Department of Pharmacology, Ballerup DK-2750, Denmark
3. Department of Biological Sciences and the College of Veterinary Medicine, Mississippi State University, Starkville, MS 39762
4. Neonatology Clinic, State University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
5. Research Department of Human Nutrition, Royal Veterinary and Agricultural University, Frederiksberg, Denmark
6. U.S. Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Houston, TX 77030