Acknowledgments
This work was financially supported by the Gansu Province Guided Science
and Technology Innovation Project [grant number GSCXZX-2019-2],
Gansu Province Guided Science and Technology Innovation Project [grant
number GSCXZX-2019-1], and Scientific Research Projects of Colleges
and Universities of Provincial Education Department [grant number
2018C-15]. The authors thank Dr. Xingxu Zhao from College of
Veterinary Medicine, Gansu Agricultural University, who has provided
valuable guidance at every stage of writing of this manuscript.