1. a College of Water Conservancy and Civil Engineering , China Agricultural University , Beijing , People's Republic of China
2. b Key Laboratory of Agricultural Engineering in Structure and Environment, Ministry of Agriculture , People's Republic of China
3. c Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, School of Life Science , Sichuan University , Chengdu , Sichuan , People's Republic of China
4. d Sunny Daily Farm , Mianyang , Sichuan , People's Republic of China