Fig. 1

Dextran assay to access intestinal permeability in adult zebrafish (Danio rerio). In this assay, fish were gavaged with a 2% RITC-Dextran solution with a molecular weight of 10,000 Da. Representative images illustrate the transit of the fluorescent marker through the intestine for the negative control (vehicle; A-D-G; n = 7), positive control (RITC-dex + ethanol; B-E-H; n = 15), and test (RITC-dex; C-F-I; n = 15) groups. A–C: Images captured immediately postgavage. D–F: Images captured 2 h post-gavage. G–I: Images captured 4 h postgavage. We observed the presence of the labeled marker in the posterior intestine at 4 h postgavage in both the test and positive control groups. All images were acquired at excitation/emission wavelengths of 559–585 nm/600–690 nm and at a total magnification of 7×. Scale bar represents 1,000 µm and 2,000 µm. RITC, rhodamine B isothiocyanate.