1College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University,Daqing, Heilongjiang Province 163319, P. R., China.
2Division of Bacterial Diseases, National Key Laboratory of Veterinary Biotechnology,
Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, Heilongjiang Province 150001, P. R., China.
3College of Animal Science and Technology, Jilin Agricultural University, Changchun,
Jilin Province 130118, P. R., China.
Email: [email protected]