1. Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, Hunan International Joint Laboratory of Animal Intestinal Ecology and Health, College of Life Sciences, Hunan Normal University , Changsha 410081 , China
2. College of Animal Science, South China Agricultural University , Tianhe District, Guangzhou 510642 , China
3. Department of Animal Science, University of Manitoba , Winnipeg, MB R3T 2N2 , Canada