Funding for this research was provided by:
National Natural Science Foundation of China (31702270)
Natural Science Foundation of Heilongjiang Province (H2016102)
Received: 4 August 2018
Accepted: 5 April 2019
First Online: 29 May 2019
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of the Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences. The animal blood samples had been obtained commercially from the farms.
: Not applicable.
: The authors declare that they have no competing interests.
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