1. College of Animal Science, Guangdong Provincial Key Laboratory of Animal Nutrition Control/Guangdong Laboratory for Lingnan Modern Agriculture/State Key Laboratory of Swine and Poultry Breeding Industry, South China Agricultural University, Guangzhou 510642, China
2. Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong SAR 999077, China