Effect of Early Pathogenic Escherichia coli Infection on the Intestinal Barrier and Immune Function in Newborn Calves.

Lina He,Han Aricha,Chen Zhang,Yinxue Cui,Huasai Simujide,Chunjie Wang,Chen Aorigele,Bo Liu,Jian Zhang

doi:10.3389/fcimb.2022.818276

Lina He, Han Aricha + Show 7 more

Open Access

https://doi.org/10.3389/fcimb.2022.818276

Copy DOI

Abstract

We studied the effect of early pathogenic Escherichia coli infection on newborn calves’ intestinal barrier and immune function. A total of 64 newborn Holstein male calves (40–43 kg) were divided into two groups: normal (NG) and test (TG), each with 32 heads. At the beginning of the experiment, the TG calves were orally administered pathogenic E. coli O1 (2.5 × 1011 CFU/mL, 100 mL) to establish a calf diarrhea model. In contrast, the NG calves were given the same amount of normal saline. During the 30 d trial period, the feeding and management of the two groups remained constant. Enzyme-linked immunosorbent assay, quantification PCR, and high-throughput 16S rRNA sequencing technology were used to detect indicators related to the intestinal barrier and immune function in the calf serum and tissues. Pathogenic E. coli O1 had a significant effect on calf diarrhea in the TG; it increased the bovine diamine oxidase (P < 0.05) and endotoxin levels in the serum and decreased (P < 0.05) the intestinal trefoil factor (P < 0.05), Occludin, Claudin-1, and Zonula Occludens 1 (ZO-1) levels in the colon tissue, as well as downregulated the mRNA expression of Occludin, Claudin-1,and ZO-1 in the colon mucosa, leading to increased intestinal permeability and impaired intestinal barrier function. Additionally, pathogenic E. coli had a significant impact on the diversity of colonic microbial flora, increasing the relative abundance of Proteobacteria at the phylum level and decreasing the levels of Firmicutes and Bacteroides. At the genus level, the relative abundance of Escherichia and Shigella in the TG increased significantly (P < 0.05), whereas that of Bacteroides, Butyricicoccus, Rikenellaceae_RC9_gut_group, Blautia, and Lactobacillus was significantly decreased (P < 0.05). In addition, the level of IL-6 in the serum of the TG calves was significantly increased (P < 0.05), whereas the IL-4 and IL-10 levels were significantly decreased (P < 0.05), compared to those in the NG calves. Thus, pathogenic E. coli induced diarrhea early in life disrupts intestinal barrier and impairs immune function in calves.

Highlights

With the continuous development of the cattle industry, calf diarrhea has brought substantial economic losses
Diarrhea symptoms appeared in the calves of the test group (TG) 12 h after an oral administration of a suspension of pathogenic E. coli O1
Because the Ace and Chao indices are directly proportional to microbial diversity, our findings indicate that the diversity of intestinal flora of newborn calves increased with age

Summary

Introduction

With the continuous development of the cattle industry, calf diarrhea has brought substantial economic losses. Bacterial diarrhea accounts for 30% of calf diarrhea. Pathogenic Escherichia coli is the most common causative agent of bacterial diarrhea (Alomari et al, 2021). Pathogenic E. coli O1 destroys the intestinal barrier and increases inflammatory factor levels and intestinal permeability, resulting in the outflow of macromolecular substances and diarrhea (Jia et al, 2018). The intestinal tract of newborn calves lacks a stable structure, and the intestinal flora is unstable, making it more vulnerable to pathogenic microorganisms and causing intestinal diseases. Many microorganisms colonize the gastrointestinal tract of newborn calves from the external environment. Once the intestinal microbial barrier is compromised, many pathogenic bacteria can colonize the intestinal tract and cause inflammation (Qin et al, 2010)

Methods

Results

Discussion

Conclusion