1. Laboratory of Animal Behavior and Environmental Science, Graduate School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki-shi, Kanagawa 214-8571, Japan
2. Laboratory of Animal Behavior and Environmental Science, School of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki-shi, Kanagawa 214-8571, Japan
3. Department of Basic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagide, Gifu-shi, Gifu 501-1193, Japan
4. Laboratory of Veterinary Physiology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
5. Basic Animal Medicine, Cooperative Division of Veterinary Sciences, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
6. Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano-shi, Kanagawa 257-8523, Japan