1. Institute of Animal Nutrition, University of Zurich, CH-8057 Zurich, Switzerl
2. Institute of Agricultural Sciences, ETH Zurich, CH-8092 Zurich, Switzerl
3. Research Institute of Organic Agriculture, CH-5070 Frick, Switzerl
4. Center for Applied Biotechnology and Molecular Medicine, CH-8057 Zurich, Switzerl