1. College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, Harbin 150030, P.R. China
2. College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing High-tech Industrial Development Zone, Daqing 163319, P.R. China
3. Jiangsu Engineering Technology Research Center of Meat Sheep & Goat Industry, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P.R. China
4. Center for Molecular Metabolism, School of Environmental and Biological Engineering, Nanjing University of Science Technology, Nanjing 210095, P.R. China