Funding for this research was provided by:
Ministry of Science and Technology of the People's Republic of China (2016YFD0500300)
Received: 27 June 2020
Accepted: 23 February 2021
First Online: 6 March 2021
: This study was carried out in accordance with the principles of the Basel Declaration and recommendation of the Animal Ethics Committee of Shenyang Agricultural University. The sampling protocol was approved by the Animal Ethics Committee of Shenyang Agricultural University (Aproval number: 201606090). No animals were harmed during the sampling process. The written permission was obtained from the managers of the zoos and schools before the faecal samples were collected.
: Not applicable.
: The authors declare that they have no conflict of interest.