1. Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
2. Laboratory of Animal Science, Department of Applied Biological Sciences, Setsunan University, Osaka 573-0101, Japan
3. Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
4. Okinawa Zoo Animal Hospital, Okinawa Zoo and Museum, Okinawa 904-0021, Japan
5. Institute of Zoology, Chinese Academy of Sciences, 1-5 Beichen West Road, Chaoyang, Beijing, China