**Muhammad Zahoor Khan1, *Zhi-Jun Cao1, *Adnan Khan1
1 College of Animal Science and Technology, China Agricultural University, Beijing 100193, P. R. China
*All authors equally contributed to this work
**Corresponding Author
Dr. Muhammad Zahoor Khan (Ph.D.),
College of Animal Science and Technology
China Agricultural University, Beijing, China.
Email: zahoorcau@cau.edu.cn