Funding for this research was provided by:
National Natural Science Foundation of P.R. China (No. 31372428)
Priority Academic Program Development of Jiangsu Higher Education Institutions (regular)
Received: 25 October 2017
Accepted: 26 March 2018
First Online: 4 April 2018
Ethics approval and consent to participate
: The animal handling procedures complied with the guideline of the Animal Ethics Committee of Nanjing Agriculture University, China and all animal experiments complied with the guidelines of the Animal Welfare Council of China. The experimental protocols were approved by the Science and Technology Agency of Jiangsu Province (Protocol code SYXK (SU) 2010-0005).
: Not applicable.
: The authors declare that they have no competing interests.