Funding for this research was provided by:
National Natural Science Foundation of China (31672512)
Special Fund for Agro-scientific Research in the Public Interest (201003011)
The Fundamental Research Funds for the Central Universities (KYZ201212)
the Priority Academic Program Development of Jiangsu Higher Education Institutions
Received: 26 April 2017
Accepted: 14 December 2017
First Online: 18 January 2018
: The Animal Ethics Committee of Nanjing Agricultural University approved the experimental protocol, with the project number 31672512. The sampling procedures complied with the “Guidelines on Ethical Treatment of Experimental Animals” (2006) No. 398 set by the Ministry of Science and Technology, China.
: Not applicable.
: The authors declare that they have no competing interests.