Supported by National Natural Science Foundation of China(31572492,21371103,31072109,31372482);Tianjin College Outstanding Young Teachers Scheme(J010070501);the Science and Technology Development Fund of Tianjin Agricultural University(2014N03);the Natural Science Foundation of Tianjin(12JCZDJC22100);the Veterinary Biotechnology Scientific Research Innovation Team of Tianjin(TD12-5019);the Veterinary"Leading Talent Culture Project"of Tianjin;Tianjin College Students Innovation and Entrepreneurship Training Program(201610061005)