A Taylor dispersion framework links peristaltic flow to glucose absorption in the intestine of zebrafish larvae

Peristaltic motility shapes luminal transport and thus nutrient uptake, yet direct in vivo links between motility, flow, and absorption remain scarce. Here, leveraging the optical transparency of zebrafish larvae, we combine fluorescence imaging and particle tracking to quantify peristalsis, intestinal flow, and glucose uptake measured by gallbladder fluorescence after oral delivery of fluorescent glucose. We define a motility–flow index from contraction frequency and amplitude together with flow intensity and show that it predicts nondimensional uptake in a manner consistent with Taylor–Aris dispersion. Acetylcholine increased motility, strengthened flow, and enhanced glucose absorption. In contrast, dextran sulfate sodium induced inflammation, flattened intestinal folds, suppressed motility and flow, and shifted transport toward a low Péclet number regime consistent with entropic slowdown. Across normal and inflamed conditions, absorption collapsed onto a single quadratic relation with the motility–flow index. Liposome coadministration enhanced uptake by comparable factors in both groups. Together, these results indicate that motility driven transport is the dominant source of uptake variation under the present conditions, and provide an in vivo benchmark and a generalizable theoretical–experimental framework for dispersion based descriptions of intestinal absorption in systems where the peristaltic wavelength and period and the intestinal geometry are quantitatively accessible.