1. Laboratory of Molecular Morphology, Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 657–8501, Japan
2. Faculty of Agriculture, University Farm, Kagawa University, Sanuki, Kagawa 769–2304, Japan
3. Environmental Science and Technology, Graduate School of Science and Technology, Niigata University, Niigata, Niigata 950–2181, Japan
4. Laboratory of Animal Nutrient Metabolism, Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 657–8501, Japan
5. Laboratory of Histophysiology, Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 657–8501, Japan