<i>Lactobacillus reuteri</i> Enhances the Mucosal Barrier Function against Heat-killed <i>Salmonella</i> Typhimurium in the Intestine of Broiler Chicks

Abstract

Salmonella Typhimurium (ST) infection in chickens inhibits their growth and can lead to food-borne diseases in humans. Probiotics are expected to enhance the function of host intestinal barrier against pathogen infection. The aim of our study was to determine the effect of viable Lactobacillus reuteri (LR) on the response of the mucosal barrier function to antigen stimulation in broiler chicks. Day-old male (n＝8) and female (n＝4) broiler chicks were orally administered either 1×10 8 LR or a water-only control, every day for 7 days. After 7 days, either 1×10 8 heatkilled ST (k-ST), or a buffer-only control, was administered via intra-cardiac injection. The ileum and cecum were collected 3 h post-injection, and paraffin sections were prepared for either mRNA extraction (males), or gut permeability tests (females). Villus and crypt lengths were determined via histological analysis. Real-time PCR was used to calculate expression levels of Toll-like receptors (TLRs), pro-inflammatory cytokines, anti-inflammatory cytokines, avian β-defensins, and tight-junction-associated molecules. Gut permeability was assessed using the inverted intestine method. We found that (1) expression of TLR2-1, TLR21, TGF-β2 and TGF-β3 were reduced following k-ST stimulation, but were unaffected by LR-treatment; (2) oral administration of LR led to increased Claudin1, Claudin5, ZO2, and JAM2 expression following k-ST stimulation; (3) cecal permeability was reduced by co-treatment with LR and k-ST, but not by treatment with LR or k-ST alone. These results suggest that LR, as used in this study, may enhance the intestinal mucosal physical barrier function, but not the expression of other immunerelated factors in newly hatched chicks.

Relationship between Mucosal Barrier Function of the Oviduct and Intestine in the Productivity of Laying Hens

“…In our study, L. reuteri treatment increased the gene expression of JAM2 in the digestive tract of broiler chicks (Nii et al, 2020c). L. reuteri also increased the expressions of Claudin1, Claudin5, JAM2, and ZO2, and decreased cecal permeability in the cecum of Salmonella Typhimurium heat-killed bacteria stimulated broiler chicks (Nii et al, 2020d). In addition, L. reuteri and C. butyricum treatment enhanced the expression of TLRs, AvBDs, and pro-and anti-inflammatory cytokine genes (Terada et al, 2020).…”

“…Our previous study showed that oral administration of 1 × 10 8 cfu of L. reuteri increased villus height in the ileum of broiler chicks (Nii et al, 2020c;Nii et al, 2020d). Therefore, probiotics are expected to improve intestinal health by increasing the V/C ratio.…”

Intravaginal injection of Lactobacillus johnsonii may modulates oviductal microbiota and mucosal barrier function of laying hens

“…Probiotics are beneficial live bacteria that improve host animal health. The function of them has been well studied for its positive effects on intestinal health in poultry ( Awad et al, 2010 ; Nii et al, 2020a ). Lactobacillus and Bifidobaterium are biological barriers in the intestinal mucosal microflora that maintain the mucosal immune system by suppressing adhesion and colonization of pathogenic bacteria ( O'Hara and Shanahan, 2006 ).…”

Ecological Adaptations of Gut Microbiota Members and Their Consequences for Use as a New Generation of Probiotics

“…Instead, other genera and species are more characteristic for distal parts of the intestinal tract, and this is common among distantly related species such as humans, pigs or chickens ( Figure 1 ). Despite this, Lactobacilli and Bifidobacteria are used in all these species as probiotics [ 26 , 27 , 28 ],. In some cases, even the same species, such as Lactobacillus plantarum , has been tested in different hosts [ 29 , 30 , 31 ].…”