1. Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Medicine, Universidade de Santiago de Compostela, 27002 Lugo, Spain
2. Feiraco Sociedade Cooperativa Galega, Ponte Maceira s/n, 15864 Ames, Spain
3. Pediatric Gastroenterology Unit, 15106 Corunna, Spain