The Protective Effect of E. faecium on S. typhimurium Infection Induced Damage to Intestinal Mucosa.

Qinghua Yu,Hang Zhang,Stoffel Matjeke Radebe,Junpeng Jia,Minjuan Wang,Jiayi Zhao

doi:10.3389/fvets.2021.740424

Abstract

Intensive farming is prone to induce large-scale outbreaks of infectious diseases, with increasing use of antibiotics, which deviate from the demand of organic farming. The high mortality rate of chickens infected with Salmonella caused huge economic losses; therefore, the promising safe prevention and treatment measures of Salmonella are in urgent need, such as probiotics. Probiotics are becoming an ideal alternative treatment option besides antibiotics, but the effective chicken probiotic strains with clear protective mechanism against Salmonella remain unclear. In this study, we found Enterococcus faecium YQH2 was effective in preventing Salmonella typhimurium infection in chickens. Salmonella typhimurium induced the loss of body weight, and liver and intestinal morphology damage. The inflammatory factor levels increased and intestinal proliferation inhibited. However, after treatment with Enterococcus faecium YQH2, broilers grew normally, the pathological changes of liver and intestine were reduced, and the colonization of Salmonella in the intestine was improved. Not only that, the length of villi and the depth of crypts were relatively normal, and the levels of inflammatory factors such as IL-1β, TNF-α, and IL-8 were reduced. The number of PCNA cells of Enterococcus faecium YQH2 returned to normal under the action of Salmonella typhimurium infection, which was conducive to the normal proliferation of intestinal epithelial cells. The protective effect of Enterococcus faecium YQH2 may be due to the attribution to the activation of hypoxia and then induced the proliferation of intestinal stem cells to repair the damage of intestinal mucosa under Salmonella typhimurium infection. This study demonstrated that Enterococcus faecium YQH2 was effective in preventing Salmonella typhimurium infection, which could be further used in the chicken health breeding.

Highlights

With the improvement of people’s living standards and the increase in demand for livestock and poultry products, strict health cultivation of chickens shows a sharp increase
Compared with chickens infected with Salmonella, the weight of chickens treated with E. faecium YQH2 for 20 consecutive days returned to normal (Figures 1A,B)
Salmonella typhimurium–infected chickens treated with E. faecium YQH2 reduced ileal bleeding points and significantly improved liver, intestinal morphology, and villus length

Summary

Introduction

With the improvement of people’s living standards and the increase in demand for livestock and poultry products, strict health cultivation of chickens shows a sharp increase. With the rapid development of the livestock and poultry breeding industry, the diseases acquired by livestock and poultry have shown an increasing trend year by year [2]. Protective Effect of E. faecium become an important element restricting the development of many country’s agriculture industry. Salmonella is often present in the intestines of many farm animals, especially in chickens [3, 4]. There is the evidence that people are susceptible to intestinal infections if they ate large amounts of chickens contaminated with Salmonella or come into direct contact with sick chickens [5, 6]. Salmonella typhimurium (S. typhimurium) was known to cause severe gastro-intestinal inflammation and even death, which has caused great harm to the agriculture industry [7, 8]. We need to find effective ways to strengthen the prevention, diagnosis, and treatment of salmonellosis

Methods

Results

Conclusion