1. Department of Animal Products Institute of Livestock and Grassland Science NARO Ikenodai 2 Tsukuba Ibaraki 305‐0901 Japan
2. Western Region Agricultural Research Center NARO 1‐3‐1 Senyu‐cho Zenstuji Kagawa 765‐8508 Japan
3. Food Research Institute NARO 2‐1‐12 Kannondai Tsukuba Ibaraki 305‐8642 Japan
4. Toguchi Company 2‐8‐43 Agarie Nago Okinawa 905‐0021 Japan