In 2020, we successfully achieved downsizing of DIO-zebrafish and established a model for visceral fat accumulation using juvenile zebrafish. The use of adult zebrafish in DIO experiments allowed for various analyses comparable to mouse models, including evaluation of body weight gain, visceral fat content, analysis of neutral lipids, total cholesterol, fatty liver, and liver parameters. However, conducting tests with a large number of animals, such as 100 animals at once, was labor-intensive.
  By using zebrafish juveniles at 3 weeks post-fertilization, measuring 1-2 cm in length, this labor-intensive process was improved, and assays with up to 5 animals per well in a 6-well plate became possible. The red regions in the images represent visceral fat, which can be observed through in vivo imaging. We are currently utilizing this model for screening assays and identification of active compounds from natural products.