The experimental use of animals and the procedures were approved by the Animal Care and Use of Committee of Dankook
University (Cheonan, South Korea).
2.1. Preparation of delta-aminolevulinic acid
The ALA used in this study, which was prepared and supplied by Easy Bio System Inc. (Seoul, South Korea), were produced
by recombinant Escherichia coli containing Rhodobacter capsulatus hemA gene. The ALA was separated by HPLC to supply a
final product with ALA 900 g/kg and 100 g/kg of dextrin