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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Endemic Poultry Viral Diseases Research » Research » Research Project #428670

Research Project: Integrative Strategies to Mitigate Enteric Diseases of Poultry

Location: Endemic Poultry Viral Diseases Research

Project Number: 6040-32000-076-00-D
Project Type: In-House Appropriated

Start Date: Aug 14, 2018
End Date: Sep 30, 2021

1. Determine the molecular mechanisms of virulence within and across Eimeria strains affecting poultry and investigate the genetic and phenotypic responses by the bird. 1.A. Isolate, sequence and propagate strains of E. tenella, E. maxima, and E. acervulina to identify genotypes/virulence genes associated with infection. 1.B. Investigate the molecular mechanisms of virulence associated with co-infection of multiple Eimeria species. 1.C. Investigate the effect of host genotypes and environmental interaction that predisposes birds to infection with different Eimeria species. 2. Determine the molecular mechanisms of virulence to Clostridium perfringens based enteritis and genotypic and phenotypic responses by the bird. 2.A. Sequence virulent field strains of C. perfringens and identify genotypes/virulent genes associated with gut damage, and body weight loss. 2.B. Investigate host genotype and phenotypic response that predisposes young birds to C. perfringens-induced enteritis. 3. Determine whether there is a causative link with Eimeria and/or clostridial based enteritis with poultry food-borne pathogen proliferation (in vivo) and shedding potential. 3.A. Study the alteration in gut microbiota associated with Eimeria- and C. perfringens-induced enteritis in commercial birds. 3.B. Develop quantitative methods to assess poultry food-borne pathogen proliferation (in vivo) and shedding potential, and use these methods to investigate if Eimeria- and C. perfringens-induced alteration in gut microbiota influence food-borne pathogen proliferation and shedding potential. 4. Develop alternatives to antibiotics for preventing or treating Eimeria- and C. perfringens-based enteritis. 4.A. Investigate the effects of sodium butyrate on cecal microbiota and host physiological response to Eimeria- and C. perfringens-induced enteritis in commercial birds. 4.B. Investigate probiotics as antibiotic alternatives for C. perfringens-induced enteritis in commercial birds. 4.C. Investigate the effects of dietary tropic amino acids such as threonine, arginine and glutamine on gut development/integrity, and host physiological response to Eimeria- and C. perfringens-induced enteritis.

The four objectives include a combination of basic and applied research that will generate knowledge and help develop tools to our ability to prevent, control, and allow broilers to adapt to coccidiosis and necrotic enteritis resulting from clostridial infection. Further, it will explore modes of action of intestinal modifiers (often referred to as antibiotic replacements) to develop precise situational application in minimizing the effects of and/or improve the bird’s recovery from coccidiosis and necrotic enteritis. Lastly, it will confirm or refute whether the progression and presence of intestinal enteritis from these conditions provides a foothold for proliferation and shedding of food-borne pathogens. These research goals are highly inter-related and will be accomplished with similar tools through a combination of controlled bird challenge studies and in-field studies to further understand underlying biological processes of the bird’s and gastro-intestinal microbiome responses during pathogen proliferation, disease progression, adaptation to and recovery from infection. The first objective includes further characterization (sequencing presence/absence as well as expression) of virulence factors in Eimeria. Further work will focus on our understanding of differential responses to those virulence factors between birds, encompassing the genotypic, endocrine, immunological, and microbial shifts associated with ranges of responses between birds. Similar approaches will be accomplished in the second objective with secondary infections of Clostridium perfringens. With this knowledge, further tools will be developed through novel vaccine development against C. perfringens. The combination of the above studies will allow us to simultaneously determine shifts in the gastro-intestinal microbiome and further our understanding of microbial niches for food-borne pathogen presence and persistence. To understand further the third objective, we will partner the industry to investigate conventional versus no antibiotic ever (NAE) production systems on changes to the gastro-intestinal microbiota and incidence, prevalence, and persistence of food-borne pathogens in those production systems in concert with a documented severity of intestinal enteritis. Our last objective is to further our knowledge of existing and new feed additive/nutritional approaches to alleviation of enteritis derived from Eimeria with or without C. perfringens. Specifically, our understanding of the effects of butyrate (and butyrate derivatives), probiotics and amino acids relay on biological responses of the bird and its microbiome will be investigated.