EthicsĀ statement
This study was performed according to the animal welfare guidelines of the World Organization for Animal Health, and animal sampling was strictly carried out in accordance with guidelines established by the Ethics of Animal Experiments of Northwest A&F University, Yangling, China. All protocols were approved by the committee (Permit Number: 2014BAD23B11). The field study did not include endangered or protected species. No specific permissions were required for the collection of samples because the samples were collected from public or non-protected areas.