1. Animal Nutrition Group, Wageningen University, PO Box 338, 6700, AH Wageningen, The Netherlands
2. Institute of Animal Science and Veterinary Pharmaceutics, Chinese Academy of Agricultural Sciences, Lanzhou 730050, China
3. Cell Biology and Immunology, Wageningen University, PO Box 338, 6700, AH Wageningen, The Netherlands
4. Animal Production Systems Group, Wageningen University, PO Box 338, 6700, AH Wageningen, The Netherlands