1. Laboratories of Biochemistry, Department of Biomedical Sciences, Graduate School of Veterinary Medicine; Hokkaido University; Sapporo 060-0818 Japan
2. Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine; Menoufia University; Menoufia 32721 Egypt
3. National Agricultural Research Center for Hokkaido Region; Sapporo 062-8555 Japan