1. College of Animal Science and Technology, Southwest University, Chongqing 400715, China
2. Chongqing Key Laboratory of Herbivore Science, Southwest University, Chongqing 400715, China
3. College of Food Science, Southwest University, Chongqing 400715, China
4. Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Government of Canada, 6000 C&E Trail, Lacombe, AB T4L 1W1, Canada