Understanding the beneficial role of Faecalibacterium prauznitzii in avian gut health

Manipulation of the chicken intestinal microbiome to reduce the carriage of foodborne bacterial pathogens, such as Salmonella and Campylobacter that colonise the chicken caeca, is seen as a key tool in their control without the use of antimicrobial drugs. Probiotics, prebiotics and even cultured intestinal flora products are all marketed within the EU, though all have been developed by largely empirical processes and have limited efficacy.

We have pioneered the use of caecal microbiome transplants (CMT) as a tool define the role of the microbiome in both exclusion of pathogens and immunological development and are highly effective in reducing Campylobacter transmission and Salmonella colonisation in broiler (meat) chickens (Pottenger et al, 2022). This approach in conjunction with microbiome sequencing approaches to identify the key taxa associated with protective effects and have shown increased level of Faecalibacterium prauznitzii (FP) associated with decreased levels of Salmonella. FP is an anaerobic bacterium considered beneficial to mammalian gut health, that produces high levels of buyrate in the gut along with increased functional of the intestinal barrier, though its role in the chicken is not yet described. Through a combination of in vitro and in vivo approaches we aim to determine the role of FP in protection against salmonellosis and how this may be applied in its control in chickens.

Aims and objectives

The central hypothesis of this proposal is that higher levels of FP in the chicken gut microbiome promote gut health and reduce pathogen colonisation. The overarching aim is to determine the role of FP in reducing Salmonella colonisation in the chicken and seek to develop prebiotic and probiotic approaches to utilise FP in control of salmonellosis. To achieve this, we have three main objectives:

1. Development of FP culture from chicken gut
2. Assess the effect of FP and culture supernatant on a chicken epithelial cell Salmonella and Campylobacter infection model in terms of invasion and regulation of inflammatory/immune response.
3. Determine and select prebiotic plant-based diets high in complex oligosaccharides and inulin which promote FP levels in the chicken caecal microbiome2 and test against Salmonella challenge

Methodology

1. FP culture- anaerobic culture based on literature for use in cell-based assays described below (skills in bacterial culture)
2. Cell-based model using the 811E chicken epithelial cell line. This was well-established in my lab at Liverpool and can be used to assess invasion by Salmonella and Campylobacter, expression of key inflammatory cytokine and chemokine markers and the integrity of epithelial tight junctions. The model can assess how both live bacteria and culture supernatants can inhibit invasion via competitive exclusion or can modulate the immune and inflammatory response to challenge (skills in cell culture, infection models and immunology)
3. Select a panel of up to 5 potential complex carbohydrates as prebiotic candidates added as feed supplements to small groups of broiler chicks in the CIEL Poultry Unit at Langford. Candidates will be selected based on literature as suitable for use in chicken and potential to promote high levels of FP in the caeca. At 21 days chicks will be euthanased and caecal contents taken. We will use 16S amplicon sequencing to determine the structure of the microbiome under each feed regimen and targeted qPCR to quantify FP levels in the gut. (In vivo skills, sequencing and microbiome analysis)
4. Based on #3, we will select the candidate prebiotic with the greatest effect on FP levels and compare the levels of Salmonella following challenge in birds with diets with or without the candidate prebiotic via clocal swabs and quantitative bacteriology at post mortem examination

Apply for this project

This project will be based in Bristol Veterinary School.

Please contact bvs-pgrstudent-admin@bristol.ac.uk for further details on how to apply.

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