Dose titration of FITC-D for optimal measurement of enteric inflammation in broiler chicks

Abstract

Traditionally, antibiotic growth promoters (AGP) have been used in foodstock animals to reduce enteric inflammation and maintain intestinal homeostasis, thus improving growth and performance. Due to increasing restrictions regarding the use of AGP however, precise and high throughput enteric inflammation models and markers to search for effective alternatives are urgently needed. In this paper, oral administration of fluorescein isothiocyanate dextran (FITC-d, 3-5 kDa) and its passage into blood was used as a marker for tight junction permeability. In experiement 1, broilers were assigned to a control group, a group which received 24 h feed restriction (FR), or a group which received dextran sodium sulfate (DSS) (0.75% in water for 5 d), and each group then underwent an oral gavage of FITC-d 2.5 h before sample collection on d10. FITC-d in serum and intestinal samples (duodenum and ceca) were found to be higher (P<0.05) after FR than in the DSS and control groups. In experiment 2, FR was evaluated for its effect on mucosal leakage and an oral dose of FITC-d of 0.5, 1.1, or 2.2 mg/chick was used to measure the gastrointestinal tract (GIT) permeability at 6 d of age. The amount of FITC-d remaining in the duodenal tissue of the control birds increased with dose, only the 1.1 mg FITC-d/chick dose resulted in differences (P<0.05) between the control and FR groups. No differences were noted between the control and FR groups, regardless of FITC-d dosage in cecal recovery of FITC-d. Additionally, FR increased FITC-d serum levels when compared to the control group and in a dose-dependent manner. Experiment 3 compared serum levels after administration of 0.55 and 1.1 mg/chick doses of FITC-d in birds treated with FR, rye-based diet (RBD), and DSS. Intestinal sections were collected for FITC-d recovery in the 1.1 mg dosage group. All inflammation treatments significantly increased serum FITC-d levels at both doses. Only FR resulted in increased (P<0.05) FITC-d recovery from duodenum, ileum, and ceca. In conclusion, FR, DSS, and RBD affected GIT tight junction integrity, suggesting their value for enteric inflammation models, and FITC-d may be a good indicator of permeability.

Intestinal permeability induced by lipopolysaccharide and measured by lactulose, rhamnose and mannitol sugars in chickens

“…The interaction between the LPS dose and time points for individual sugars was not statistically significant. In addition, birds in these experiments were fasted for 19.5 h and recently it has been shown that 24 h fasting increased IP in chickens (Kuttappan et al, 2015;Vicuna et al, 2015b). To exclude the possible interference of fasting with LPS, a third experiment at 1 mg/kg BW without fasting was conducted.…”

“…These variations and limited published data may need further investigations. Fluorescein isothiocyanate dextran has a high molecular weight of 40 kDa and increased serum concentrations indicate increased IP in chickens (Kuttappan et al, 2015;Vicuna et al, 2015a and2015b). However, DSS ingestion and fasting were utilized as models of increased IP, compared with the LPS model in the current studies.…”

“…Fluorescein isothiocyanate dextran, diamine oxidase, D-lactate and zonula occludens tight junction proteins in blood Fluorescein isothiocyanate dextran analysis was conducted as previously described (Vicuna et al, 2015b). In brief, standards (0, 0.0001, 0.001, 0.01, 0.1, 1.0 and 10 µg/ml) were prepared using the same FITC-d sugars as for oral gavage.…”

“…Dextran sodium sulphate (DSS) ingestion, fasting (Kuttappan et al, 2015;Vicuna et al, 2015b), dexamethasone (Vicuna et al, 2015a) and wire floor stress (Wideman et al, 2012) have recently been employed as models of increased IP in chickens. These studies have been conducted in one strain of chickens (Cobb).…”

“…Recently, diamine oxidase (DAO), D-lactate (Wu et al, 2013;Li et al, 2015) and fluorescein isothiocyanate dextran (FITC-d) (Vicuna et al, 2015b) concentrations in blood have been utilized as in vivo biomarkers of increased IP in chickens. In addition, increased concentrations of zonula occludens (ZO-1) have been observed in celiac disease, diabetic and insulin-resistant human patients (Klaus et al, 2013).…”