1. Laboratory of Livestock Physiology, Immunology and Genetics, Department of Biosystems, Kasteelpark Arenberg 30, B-3001 Leuven, Belgium
2. Centre for Environmental Sciences, Hasselt University, 3590 Diepenbeek, Belgium
3. Department of Biochemistry and Molecular Biology, College of Biological Sciences, China Agricultural University
4. Department of Animal Production, School of Agriculture University of Lome, Togo