1. Laboratory of Veterinary Physiology, Departments of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
2. Department of Applied Chemistry and Life Sciences, Graduate School of Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan
3. Laboratory of Veterinary Virology, Departments of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan
4. Laboratory of Animal Therapeutics, Department of Veterinary Science, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan