1. State Key Laboratory of Animal Nutrition Institute of Animal Sciences of Chinese Academy of Agricultural Sciences Beijing 100193 China
2. Scientific Observing and Experiment Station of Animal Genetic Resources and Nutrition in North China of Ministry of Agriculture and Rural Affairs Institute of Animal Sciences of Chinese Academy of Agricultural Sciences Beijing 100193 China
3. College of Animal Science and Technology of China Agricultural University Beijing 100193 China
4. College of Animal Science and Technology of Qingdao Agricultural University Qingdao 266109 China