Concurrent feeding of PED6, EnzChek, and fluorescent microspheres enables the assessment of larval digestive function. To correct for interindividual variability observed in wild-type siblings (6 dpf) labeled with PED6 (A), multiple reporters of the digestive function can be used. (B) PED6, EnzChek and microspheres each fluoresce at distinct wavelengths, allowing simultaneous screening for lipase and protease activities, and swallowing function, respectively. (C) PED6 and EnzChek signal in the gall bladder (arrowhead) and intestine (arrow) of wild-type zebrafish. Microspheres in the intestine indicate normal ingestion. (D) Intestinal protease and phospholipase activity correlate, validating the use of the ratio of PED6 to EnzChek signal as readout of the digestive function. Figure from Hama et al. (2008), Am. J. Physiol. Gastrointest. Liver Physiol., used with permission from Am. Physiol. Soc.