Funding for this research was provided by:
the Fundamental Research Funds for the Central Universities (No. 2662018PY043)
the National Project for Breeding of Transgenic Pig (No. 2016ZX08006-002)
Received: 1 March 2019
Accepted: 29 October 2019
First Online: 8 November 2019
Ethics approval and consent to participate
: No human and animal were involved in the present study. The methods were carried out in accordance with approved guidelines from Huazhong Agricultural University. All of the experimental protocols were subject to approval by the Ethics Committee of Huazhong Agricultural University (HZAUMU2013-0005).
: This article is distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (ExternalRef removed).
: The authors declare that they have no competing interests.