Early inoculation with caecal fermentation broth alters small intestine morphology, gene expression of tight junction proteins in the ileum, and the caecal metabolomic profiling of broilers

Yujie Gong,Xueting Wen,Wentao Lyu,Wenrui Xia,Yingping Xiao,Hua Yang,Xiaoting Zou

doi:10.1186/s40104-019-0410-1

Abstract

BackgroundThe establishment of stable microbiota in early life is beneficial to the individual. Changes in the intestinal environment during early life play a crucial role in modulating the gut microbiota. Therefore, early intervention to change the intestinal environment can be regarded as a new regulation strategy for the growth and health of poultry. However, the effects of intestinal environmental changes on host physiology and metabolism are rarely reported. This study was conducted to investigate the effects of early inoculation with caecal fermentation broth on small intestine morphology, gene expression of tight junction proteins in the ileum, and cecum microbial metabolism of broilers.ResultsOur data showed that early inoculation with caecal fermentation broth could improve intestine morphology. The small intestine villus height was significantly increased (P < 0.05) in the intervened broilers compared to the control group, especially on day 28. A similar result was observed in the ratio of villus height to crypt depth (P < 0.05). Meanwhile, we found early inoculation significantly increased (P < 0.05) the expression levels of zonula occludens-1 (ZO1) on days 14 and 28, claudin-1 (CLDN1) on day 28, whereas the gene expression of claudin-2 (CLDN2) was significantly decreased (P < 0.05) on days 14 and 28. Gas chromatography time-of-flight/mass spectrometry (GC-TOF/MS) technology was further implemented to systematically evaluate the microbial metabolite profiles. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) displayed a distinct trend towards separation between the fermentation broth group (F group) and the control group (C group). The differentially expressed metabolites were identified, and they were mainly functionally enriched in beta-alanine metabolism and biosynthesis of unsaturated fatty acids. In addition, 1,3-diaminopropane was selected as a key biomarker that responded to early inoculation with caecal fermentation broth.ConclusionsThese results provide insight into intestinal metabolomics and confirm that early inoculation with caecal fermentation broth can be used as a potential strategy to improve intestinal health of broilers.

Highlights

The establishment of stable microbiota in early life is beneficial to the individual
Accumulating evidence demonstrates that diet supplemented with probiotics [6], organic acids [7], and exogenous enzyme [8, 9] can increase the abundance of intestinal beneficial bacteria, which have a protective role as the first line of defense against pathogenic bacteria in addition to assistance in specific metabolism and gut structure integrity [10]
Our previous study has shown that shaping a specific gut environment through early intervention can alter the colonization and development of caecum microbiota in broilers, resulting in a reduction in the relative abundance of enteric pathogen and an increase of beneficial bacteria [11], the downstream effects caused by altering the structure of the gut microbiome on host physiology still need to be further explored [3]

Summary

Introduction

The establishment of stable microbiota in early life is beneficial to the individual. Changes in the intestinal environment during early life play a crucial role in modulating the gut microbiota. This study was conducted to investigate the effects of early inoculation with caecal fermentation broth on small intestine morphology, gene expression of tight junction proteins in the ileum, and cecum microbial metabolism of broilers. Our previous study has shown that shaping a specific gut environment through early intervention can alter the colonization and development of caecum microbiota in broilers, resulting in a reduction in the relative abundance of enteric pathogen and an increase of beneficial bacteria [11], the downstream effects caused by altering the structure of the gut microbiome on host physiology still need to be further explored [3]. Intestine morphology and gene expression of tight junction proteins are generally regarded as pivotal indicators of intestinal health

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