1. Laboratory of Veterinary Toxicology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
2. Swine and Poultry Research Center, Shizuoka Prefectural Research Institute of Animal Industry, 2780 Nishikata, Kikugawa-shi, Shizuoka 439-0037, Japan