MECHANISMS OF MEGASPHAERA STANTONII-MEDIATED COLONIZATION RESISTANCE AGAINST NECROTIC ENTERITIS

The primary aim of this research is to develop a cost-effective antibiotic-free solution for mitigating necrotic enteritis (NE). We recently discovered a chicken cecal commensal bacterium to be capable of inhibitingClostridium perfringensgrowth and inducing host defense peptide gene expression. Importantly, oral administration of the bacterium showed robust protection of chickens from NE. The goal of the current project is to understand the mechanisms underlying the protective action of the bacterium against NE in chickens in order to explore its potential as a probiotic for disease control and prevention against NE. The first objective is toIdentify major antibacterial and HDP-inducing metabolites produced by the bacterium.The 50 most abundantmetabolites will be identified from the overnight culture through quantitative untargeted metabolomics and short-chain fatty acid assays or through fractionation withhigh-performance liquid chromatography. These metabolites responsible for anti-C. perfringensand/or HDP-inducing activity will be identified through individual evaluations and mass spectrometry. Subsequently, the second objective is to elucidate the mechanism through which the major metabolites resistC. perfringenscolonization bothin vitroandin vivo.The antibacterial mechanisms of major metabolites will be assessed by observing their effects on the membrane structure ofC. perfringensusing electron microscopy. Additionally, the impact of the metabolites ontranscriptional response ofC. perfringenswill be analyzed. Additionally, the influence of the bacterial metabolites on the development of intestinal microbiota, immunity, and barrier function will be evaluated in healthy chickens and in a chicken model of NE using a range of multi-omics techniques.