Table 1.

Summary of studies for models, method of evaluation and nutritional modulation of intestinal permeability (IP) in chickens.¹

Models	Method of IP assessment	Dietary changes affecting IP	References
Aflatoxins	(1) Bacterial translocation (BT); (2) FITC-d + BT; (3) Lactulose	(1 to 2) NA; (3) Increased protein reduced IP	(1) Galarza-Seeber et al., 2016; (2) Hernández-Ramírez et al. (2020); (3) Chen et al. (2016)
Campylobacter	(1) Escherichia coli in liver; (2) Bacterial translocation	(1) NA; (2) Bacterial translocation (reduced with probiotics and enzymes)	(1) Awad et al. (2016); (2) Gibbs et al., 2016
Coccidiosis	(1) TEER; (2) Fecal ovo-transferrin; (3) FITC-d; (4) FITC-d + TJ; (5) FITC-d + ZO-1, JAM, occludin; (6) FITC-d; (7) FITC-d and BT; (8) Escherichia coli; (9) FITC-d	(1 to 5) NA; (6) Zn reduced IP; (7) Organic acid reduced IP; (8) IP reduced by coated Sodium butyrate. (9) IP reduced by 0.5% glutamine	(1) Murugesan et al. (2014); (2) Goossens et al., 2018; (3) Chadwick et al. (2020); (4) Teng et al. (2020); (5) Schneiders et al. (2020) (6) dos Santos et al., 2020; (7) Pham et al. (2020); (8) Song et al. (2017); (9) Oxford and Selvaraj, (2020)
Dexamethasone	(1) FITC-d + BT; (2) FITC-d; (3 to 4) FITC-d	(1 to 2) NA; (3) Protein tended to reduce IP; (4) Arginine reduced IP	(1) Vicuña et al. (2015a); (2) (Macalintal et al., 2019); (3) Barekatain et al. (2019a); Barekatain et al. (2019b)
Dextran sodium sulphate	(1) FITC-d; (2) FITC + Lactulose sugars; (3) FITC-d	(1) Increased by Rye diet; (2) NA; (3) Reduced by paddy rice	(1) Vicuña et al. (2015b); (2) Gilani et al. (2017b); (3) Murai et al. (2018)
Fasting	(1) FITC-d; (2) FITC-d; (3) Iohexol; (4) Lactulose sugars; (5) FITC-d; (6) FITC-d + BT	(1 to 3) NA; (4) Olive pomace had no effect; (5) IP increased by glutamine/Sodium butyrate; (6) IP reduced by humic acid	(1) Vicuña et al. (2015b); (2) Baxter et al. (2017); (3) Wilhelm et al., 2020; (4) Herrero-Encinas et al. (2020); (5) Gilani et al. (2018b); (6) Maguey-Gonzalez et al. (2018)
Heat stress	(1) TEER; (2) FITC-d + TJ; (3) FITC-d; (4) TEER + FITC-d; (5) FITC-d; (6) FITC-d + TJ; (7) TEER; (8) TEER	(1 to 3) NA; (4) Prebiotics reduced FITC-d; (5) IP reduced by spray dried plasma; (6) Some effect of Resveratrol; (7) IP improved by betaine.	(1) Goo et al. (2019a); (2) Tabler et al. (2020); (3) Ruff et al. (2020); (4) Song et al. (2013); Song et al. (2014); (5) Ruff et al. (2020); (6) Zhang et al. (2017); (7) Shakeri et al. (2018) & (8) Shakeri et al. (2020)
Lipopolysaccharide	(1) Lactulose, FITC-d; (2) Diamine oxidase + D-lactate	(1) NA; (2) IP reduced by clinoptilolite clay	(1) Gilani et al. (2016); (2) Wu et al. (2013)
Clostridium perfringens	FITC-d + Endotoxins	Reduced by a combination of chelated and inorganic zinc	Zhang et al. (2019)
Rye	(1) FITC-d + BT; (2) Endotoxins and fatty acid binding protein gene; (3) BT; (4) FITC-d; (5) FITC-d + BT	(1 to 3) NA; (4) Reduced by salinomycin; (5) IP impacted by breed line and corn or rye diets	(1) Tellez et al. (2015); (2) Chen et al. (2015); (3) Latorre et al. (2015); (4) Naghizadeh et al. (2019); (5) Baxter et al., 2019
(1) Sal + Heat stress; (2) Sal + Coccidiosis; (3) Sal; (4) Sal + Coccidiosis; (5) Sal; (6) Sal	(1) Salmonella proliferation increased in liver; (2) FITC-d + BT; (3) Clostridium perfringens; (4) FITC-d; (5) FITC-d; (6) mRNA of occludin and claudin	(1 to 2) NA; (3) Prebiotics reduced translocation; (4) IP reduced by probiotics; (5) IP reduced by boric acid; (6) mRNA expressions increased by Zn.	(1) Quinteiro-Filho et al. (2012); (2) Latorre et al. (2018); (3) Shao et al. (2013); (4) Hernandez-Patlan et al. (2019b); (5) Hernandez-Patlan et al. (2019a); (6) Zhang et al. (2012)
(1) Stocking density; (2) feeding fines	(1) lipopolysaccharide in blood; (2) FITC-d	(1) Plasma lipopolysaccharide increased by stocking density; (2) IP increased by feeding fines	(1) Goo et al. (2019b); (2) Kenny (2019)
Used litter	(1) FITC-d; (2) Endotoxins	(1) IP reduced by phytogenic; (2) IP reduced by probiotics	(1) Vieira et al. (2020); (2) Murugesan et al. (2014)
No challenge	FITC-d	IP increased by formaldehyde and Amasil but reduced by silo health compounds	Feye et al. (2019)

FITC-d = fluorescence isothiocyanate dextran; BT = bacterial translocation; NA = not applicable; TJ = tight junction proteins; ZO-1 = zonula occludens-1; JAM = junctional adhesion molecule. TEER = transepithelial electrical resistance; Sal = Salmonella.

¹Studies are given a number from 1 to 9 in parentheses within each row of the table in the order of given references.