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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Endemic Poultry Viral Diseases Research » Research » Research Project #439671

Research Project: Genomic and Epidemiological Parameters to Inform Interventions Strategies for Enteric Diseases of Poultry

Location: Endemic Poultry Viral Diseases Research

Project Number: 6040-32000-080-000-D
Project Type: In-House Appropriated

Start Date: Sep 10, 2021
End Date: Sep 9, 2026

1. Determine the molecular mechanisms of virulence within and across Eimeria strains affecting poultry and investigate the genetic and phenotypic responses by the bird. 1.1. Produce high-quality full genome sequences of Eimeria species of economic importance in commercial poultry. 1.2. Use the rapid, high throughput molecular screening assay to differentiate Eimeria species in a sample and determine if they are of vaccine or field origin. 1.3A. Elucidate the relationship between host redox (oxidative stress) status and development of E. maxima. 1.3B. Understand host resistance/tolerance mechanisms in the development of intestinal lesions during Eimeria maxima infection. 1.3C. Identification, characterization, and assessment of non-pathogenic bacterial species from reused litter used as ‘proLitterbiotics’ during E. maxima infection. 2. Determine the molecular mechanisms of virulence to Clostridium perfringens-based enteritis and genotypic and phenotypic responses by the bird. 2.1. Sequencing and analysis of virulent field strains of C. perfringens. 2.2. Investigate host genotype and environmental interaction that predisposes young birds to C. perfringens-induced enteritis. 2.3A. Synthesize chitosan nanoparticle vaccines, loaded with antigens from field strains of C. perfringens and surface-tagged with E. maxima antigens. 2.3B. Identify the anti-C. perfringens IgA and IgG and T cell response curves in broilers inoculated orally with different doses of chitosan nanoparticle vaccine entrapped with C. perfringens and E. maxima proteins. 2.3C. Quantify the chitosan nanoparticle vaccine efficacy in decreasing the colonization of C. perfringens and disease score in broilers induced with necrotic enteritis. 3. Develop alternatives to antibiotics for preventing or treating Eimeria- and C. perfringens-based enteritis. 3.1A. Evaluate the impact of dietary antibiotic alternatives on intestinal physiology and microbial ecology in each segment of the gastrointestinal tract of genetically diverse broiler chickens in response to Eimeria- and C. perfringens-based necrotic enteritis. 3.1B. Characterization of starch digestibility along the digestive tract, digesta oligosaccharides, and SCVFAs in broiler chickens receiving different types of resistant starch (RS). 3.2. Investigate mechanisms by which probiotics influence intestinal physiology and microbial ecology of genetically diverse broilers in response to Eimeria- and C. perfringens-based necrotic enteritis. 3.3. Investigate the modes of action of dietary amino acids and nutrients on gut development/integrity, and host physiological response to Eimeria- and C. perfringens-induced enteritis. 3.3A. Potentiating the protective effects of RS with low protein and amino acid supplemented diets. 3.3B. Determine the response of broiler chickens challenged with Eimeria when fed diets with RS and low protein, AA-fortified diet. 3.3C. Investigating prebiotic-probiotic symbiosis using RS as functional fiber in broilers induced with NE. **See uploaded post plan for sub-objectives 3.1C, 3.1D, 3.3D, 3.3E and 3.3F.

The approach outlined in this integrated project is divide between three interrelated objectives. The project will employ several approaches to (1) produce high-quality full genome sequences of Eimeria species of economic importance in commercial poultry; (2) develop rapid, high throughput molecular screening assays to differentiate Eimeria species in a sample, as well as determine their origins [i.e. vaccine vs. field]; and (3) improve production efficiency by studying the influence of host genetics on resistance, susceptibility, and tolerance to Eimeria spp., and the impact of dietary redox potential (e.g. cysteine) and enteric and litter microbiota on the pathology of Eimeria spp. in chickens. To better understand the incidence of NE, which is often predisposed by coccidiosis, the project will continue collecting field isolates of C. perfringens from the southeast and mid-Atlantic regions and produce full genome sequencing and complete comparative analyses of those NE-causing strains. This approach will allow identification of predominant virulence factors in C. perfringens of commercial poultry that could serve as targets for designing and developing vaccines as alternative control measures to antibiotics. Using an established nanoparticle vaccine platform, the project will continue building this unique design and further develop and test anti-C. perfringens vaccines with the potential to be adopted by the poultry industry. In dealing with the urgent need to identify, test, and employ effective antibiotic alternatives for poultry, the project will conduct detailed activities to better understand the mechanistic actions of several candidate interventions on performance, physiological, microbial, immunological, and metabolic responses of the host. The application of well-defined probiotics, prebiotics, phytogenics, and specific nutrients during coccidiosis and NE will be used in vivo and in ovo to study the critical physiological changes that directly impact host health and performance. Parameters at the enteric and systemic levels will collectively provide strong host response correlates that can be utilized in refining the application of these potential alternatives in commercial settings.