Funding for this research was provided by:
Key project for Agriculture from Shanghai Agriculture Commission (201702080008F00068)
Received: 4 October 2018
Accepted: 16 September 2019
First Online: 28 October 2019
Ethics approval and consent to participate
: The study was submitted to and approved by Shanghai Veterinary Research Institutional Ethics Committee and a statement to this effect was included with an ID number as SHVRI-PO-2016-0276.
: Not Applicable.
: The authors declare that they have no competing interests.