Funding for this research was provided by:
National Natural Science Foundation of China (No.31872331)
Provincial Key Projects of Shaanxi (2017NY-064)
Received: 20 January 2020
Accepted: 20 May 2020
First Online: 1 June 2020
Ethics approval and consent to participate
: All sampling procedures in the present study had received prior approval from the Faculty Animal Policy and Welfare Committee of Northwest A&F University (FAPWC-NWAFU). All protocols involving animals were approved by the College of Animal Science and Technology, Northwest A&F University (Approval ID: 2017ZX08008002). Due to experimental needs, our laboratory has a long-term cooperative relationship with the pig farm, so the owner of the pig farm verbally approved the collection and use of experimental animals. Meanwhile, the FAPWC-NWAFU and the College of Animal Science and Technology of NWAFU approved this procedure.
: Not applicable.
: The authors declare no competing interests.