Modified fluorescein isothiocyanate dextran assay procedure to determine intestinal permeability in samples containing high natural or synthetic pigments

Orally administered fluorescein isothiocyanate dextran (FITC-d) has been used as an indicator for intestinal permeability in poultry research for several years. Under healthy conditions, tight junctions in the intestinal wall will not allow the large (4–6 kDa) FITC-d to enter the bloodstream. Disruption of these enteric tight junctions can occur from infections, stress responses, chronic inflammation, or even feed components. Detection of FITC-d in serum (1-h post-oral administration of FITC-d) has proven to be a reliable indicator of leaky gut syndrome (increased intestinal inflammation and tight junction damage). Administration of supplementary products in feed, particularly those high in β-carotene levels or other pigments, has resulted in strong serum background fluorescence, which can render this assay unreliable. To account for this increase in background autofluorescence, the FITC-d assay procedure has been modified to accommodate these particular serum samples.

Key Words: leaky gut, fluorescein isothiocyanate dextran (FITC-d), pigment, serum, poultry.

Presented at the 9th Symposium on Gut Health in Production of Food Animals, St. Louis, USA, 2021. For information on the next edition, click here.