1. Research Unit Nutritional Physiology “Oskar Kellner”, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
2. Research Unit Genetics and Biometry, Leibniz Institute for Farm Animal Biology (FBN), Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany
3. Institute of Microbiology, Ernst-Moritz-Arndt-University, F.-L.-Jahn-Strasse 15, 17487 Greifswald, Germany