1. College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, P. R. China
2. Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin, 150030, P. R. China
3. Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Northeast Agricultural University, Harbin, 150030, P. R. China