Supported by the Special Fund for Agro-Scientific Research in the Public Interest 20100312 by the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and by the Jiangsu Research Centre of Engineering and Technology for Prevention and Control of Poultry Disease BM2013450;公益性行业农业科研专项20130312;江苏高校优势学科建设工程;江苏省家禽疫病防控工程技术研究中心BM2013450