1. Institute of Microbiology, University of Hohenheim, Stuttgart, Germany
2. Core Facility Hohenheim, Analytical Chemistry Core Facility, University of Hohenheim, Stuttgart, Germany
3. Core Facility Hohenheim, Mass Spectrometry Core Facility, University of Hohenheim, Stuttgart, Germany
4. Institute of Animal Science, University of Hohenheim, Stuttgart, Germany
5. Carlson College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA