Effects of E. Coli Infection on the Expressions of TGF-β/Smads Signaling Pathway in Broiler Intestine

C Zhang,J Wang,H Yin,J Juang

doi:10.1590/1806-9061-2019-1101

C Zhang, J Wang + Show 2 more

Open Access

https://doi.org/10.1590/1806-9061-2019-1101

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Abstract

ABSTRACT This experiment aimed to investigate whether Escherichia coli (E. coli) infection could affect the TGF-β/smads signaling pathway in the jejunal tissue of chickens. One-day-old Cobb 500 broilers were randomly divided into 2 groups and treated with intraperitoneal E. coli or broth injection. Clinical signs of the birds were assessed every day. Spleen and bursa of Fabricius of the birds, post-infection (pi), were collected to evaluate immune organ index. Jejunal tissues were collected to ascertain the expression of TGF-βs, TβRs, and Smads. The results showed that the infected birds had significantly higher index of the spleen (24hrs and 48hrs pi) compared with birds in the control group (p 0.05). In conclusion, TGF-β/Smad signaling pathway was associated with the immune response of broilers in E. coli infection and TGF-β4 was the main subtype interacting with E. coli infection.

Highlights

The intestinal mucosa is an important assurance for health which possesses a complex epithelial barrier to a broad spectrum of inflammation, oxidative stress, and microbes (Howe et al, 2015)
The chicks infected with E. coli demonstrated huddling, shivering and inactivity
The weight of the spleen and the bursa of Fabricius reflects the immune response of chicken to some extent (Rivas & Fabricant, 1988)

Summary

Introduction

The intestinal mucosa is an important assurance for health which possesses a complex epithelial barrier to a broad spectrum of inflammation, oxidative stress, and microbes (Howe et al, 2015). Escherichia coli is one of the most common pathogens of animal intestinal flora (McDonald et al, 2001) and avian pathogenic E. coli (APEC) cause great economic loss every year in poultry (Moniri & Dastehgoli 2005). The intestinal tract is damaged when APEC is colonized in the intestinal. The disruption of the intestinal barrier affects the absorption of the nutrients and induces diseases, such as multiple organ dysfunctions, systemic inflammatory response syndrome, diarrhea, and others. TGF-β can suppress inflammatory responses to intestinal bacterial antigens and play an important role in the induction of immune tolerance (Ihara et al, 2017). Studies demonstrated that TGF-β has shown a remarkable ability to protect the epithelial barrier function from the penetration of foreign antigens through countering the effect of T-cell cytokines (Monteleone et al, 2001; Planchon et al, 1994)

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