This research was jointly supported by grants from the Chinese Academy of Sciences and Knowledge Innovation Project (Kscx2-Yw-N-051), National 863 Program of China (2008AA10Z316), Research Program of State Key Laboratory of Food Science and Technology, Nanchang University (project No. SKLF-TS-200817), Ganjiang Scholars Program at Nanchang University, National Basic Research Program of China (2009CB118806), NSFC (30901040, 30901041, 30928018, 30828025, 30771558), National Fund of Agricultural Science and Technology outcome application (2006GB24910468), National Scientific and Technological Supporting Project (2006BAD12B02-5-2 and 2006BAD12B02-5-2), Hubei Chu Tian Scholars Program, National Research Initiative Competitive Grants from the Animal Growth & Nutrient Utilization Program (2008-35206-18764) of the USDA National Institute of Food and Agriculture, and Texas AgriLife Research (H-8200).