1. College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, PR China
2. Joint International Research Laboratory of Agriculture & Agri-Product Safety, Ministry of Education, Yangzhou University, Yangzhou 225009, China
3. Mammalian Nutrition Physiology Genomics, Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, Illinois 61801, United States