1. College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
2. Institute of Swine Science, Nanjing Agricultural University, Nanjing 210095, China
3. Key Laboratory of Pig Genetic Resources Evaluation and Utilization (Nanjing) of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
4. Huai’an Academy, Nanjing Agricultural University, Huai’an 223001, China