1. Center for Fish and Wildlife Health, Institute of Animal Pathology, Vetsuisse Faculty, University of Berne, Berne 3012, Switzerland
2. Zoo Basel, Basel 4054, Switzerland
3. Section of Epidemiology, Vetsuisse Faculty, University of Zurich, Zurich 8057, Switzerland
4. DSM Nutritional Products Ltd, Basel 4052, Switzerland
5. Institute of Animal Nutrition, Vetsuisse Faculty, University of Zurich, Zurich 8057, Switzerland