1 College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China.
2 College of Animal Science and Technology, Northeast Agricultural University, Harbin, 150030, PR China.
3 College of Life Science, Northeast Agricultural University, Harbin, 150030, PR China.
4 College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China; Key Laboratory of the Provincial Education Department of Heilongjiang for Common Animal Disease Prevention and Treatment, College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, PR China. Electronic address: shiwenxu@neau.edu.cn.