1. Department of Animal Production, Fukuoka Agriculture and Forestry Research Center, 587 Oaza-Yoshiki, Chikushino, Fukuoka 818-8549, Japan
2. Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
3. Research and Development Division, Omu Milk Products Co., Ltd., 1-38-1 Shinkatsudati-machi, Omuta, Fukuoka 836-0895, Japan
4. Division of Microbiology, Department of Infectious Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka 830-0011, Japan
5. Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan
6. Laboratory of Veterinary Internal Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki 889-2192, Japan