Assay considerations for fluorescein isothiocyanate-dextran (FITC-d): an indicator of intestinal permeability in broiler chickens

Abstract

Fluorescein isothiocyanate-dextran ( FITC-d ) is being used as an indicator of intestinal paracellular permeability in poultry research. Especially with the industry moving toward antibiotic-free production, intestinal function and integrity issues have been a research focus. An increasing number of scientific conference abstracts and peer-reviewed journal publications have shown that 4-kDa FITC-d is an efficient marker candidate for measurement of intestinal permeability and can be applied in broiler research. However, experimental protocols vary by personnel, instruments used, and research institution, and potential concerns related to this assay have yet to receive the same amount of attention. Understanding protocol consistency within and across laboratories is vital for obtaining accurate, consistent, and comparable experimental results. This review is aimed to 1) summarize different FITC-d assays in broiler research from peer-reviewed publications during the past 6 yr and 2) discuss factors that can potentially affect intestinal permeability results when conducting the FITC-d assay. In summary, it is essential to pay attention to details, including gavage dose, fasting period, sample handling and lab analysis details when conducting the assay in broiler research. Differences in birds (breed/strain, age, and gender) and experimental design (diet, health status/challenge model, and sampling age) need to be considered when comparing serum FITC-d concentration results between different in vivo animal trials.

Subclinical Doses of Combined Fumonisins and Deoxynivalenol Predispose Clostridium perfringens–Inoculated Broilers to Necrotic Enteritis

“…Quantification of serum FITC-d is commonly used as an indicator for assessing intestinal paracellular permeability and magnitude of severity (Kuttappan et al, 2015). The oral administration of FITC-D passes through the disrupted intestinal epithelium and enters systemic circulation, which can be quantified in the blood (Liu et al, 2021). In this current study, the presence of and DON caused a loss in gut integrity, and this loss in gut integrity was acerbated in birds challenged with NE.…”

The Mechanism of Lipopolysaccharide Escaping the Intestinal Barrier in Megalobrama amblycephala Fed a High-Fat Diet

“…Inconsistent with our expectations, we found that high fat increased the abundance of GPR78, a marker protein of ER stress, while the IRE1/XBP1 signal pathway was not activated. Previous research confirmed that secretory cells, typically such as pancreatic islet cells, were more susceptible to stress from high fat ( 41 , 51 ). We suspected that the IRE1/XBP1 signaling pathway possibly was activated in goblet cells instead of the entire intestine.…”

Effects of Tannic Acid Supplementation on Growth Performance, Oocyst Shedding, and Gut Health of in Broilers Infected with Eimeria Maxima

“…and mucus (main protein in the intestine, MUC2) [ 41 ], indicates that pathogenic bacteria and toxins are more likely to enter the bloodstream of broilers. [ 42 ]. Consistent with the FITC-D4 permeability assay result, E. maxima infection reduced mRNA expression of ZO2, CLDN4, and MUC2 in the present study.…”