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Email Content: Poultry Industry News, Comments and more by Simon M. Shane

Necrotic enteritis: The role of tight junctions and mucosal immune responses in alleviating the effects of the disease


Emami NK, Calik A, White MB, Young M, Dalloul RA. [ Microorganisms 7:231. 2019]


The effects of dietary supplementation of PrimaLac on performance of broiler chickens during a necrotic enteritis challenge were evaluated. This study consisted of 3 treatments each with 12 replicate pens (30 birds/pen). The treatments were as follows: (1) negative control (NC): corn-soybean meal diet; (2) positive control (PC): NC + 20 mg virginiamycin/kg diet (0.450 kg Stafac®20/ton); and (3) NC + PrimaLac (1.36 and 0.91 kg/ton from 1-21 and 22-42 days, respectively). Body weight and feed intake were measured at d 8, 14, 21, 28, and 42. On d 8, small intestines of 2 birds/pen were examined for necrotic enteritis lesions, and samples were collected for evaluating gut health. The body composition (lean/fat) of birds from was also measured at the end of the trial (d 42).


The gut is the site of digestion and absorption of nutrients so any damage would lead to poor bird performance. Supplementation of PrimaLac improved gut health leading to better FCR during the grow-out period (d 0-42) compared to the control. PrimaLac protected the gut lining and reduced damages due to necrotic enteritis with less severe lesions.

Barrier function of the gut cells was also improved by PrimaLac supplementation. There are special types of proteins (called tight junctions) that seal up the space between gut cells (enterocytes) and prevent pathogens in the gut lumen from entering the body, thus preventing inflammation and disease. This helps the body to use the absorbed nutrients for growth rather than spending energy to fight pathogens, which collectively results in better growth performance.

PrimaLac supplementation balanced the immune responses in the gut by increasing the gene expression of cytokines. Cytokines are proteins that orchestrate immune responses that the host mounts against pathogens. Certain cytokines regulate such responses by preventing the immune system from overreacting and mounting unnecessary reactions, thus preserving energy and nutrients for growth.

Nutrient uptake from the gut lumen is facilitated by nutrient transporter proteins expressed by intestinal cells (enterocytes). PrimaLac supplementation increased the abundance of these proteins, resulting in improved nutrient uptake and FCR compared to the control birds.

Supplementation of PrimaLac reduced the percentage of fat and increased lean tissue percentage. The amount of lean tissue was on average 28.57 g higher in PrimaLac-supplemented birds compared to PC birds (Virginiamycin), which might be of interest for producers. This number was calculated by multiplying d 42 carcass weight by lean percentage for PrimaLac and AGP (Virginiamycin) group:

PrimaLac: 3136.84g *0.7441 = 2334.12g

AGP: 3136.88g * 0.7350 = 2305.55g


Under this naturally occurring necrotic enteritis challenge model, supplementation of PrimaLac significantly reduced intestinal lesion scores and improved FCR during the overall growth period. Moreover, the dietary addition of this probiotic improved gut barrier function by regulating the gene expression of tight junction proteins and gut mucosal immune responses.

Copyright © 2023 Simon M. Shane