1. Newport Laboratories, Worthington, Minnesota, USA
2. Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, South Dakota, USA
3. Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
4. Poultry Research Institute, Shandong Academy of Agricultural Sciences, Jinan, Shandong, China
5. Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, USA