Location: Endemic Poultry Viral Diseases Research
Project Number: 6040-32000-080-002-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Aug 30, 2027
1. Determine the molecular mechanisms of virulence within and across Eimeria strains affecting poultry and investigate the genetic and phenotypic responses by the bird. 1A. Isolate, sequence and propagate strains of E. acervulina, E. maxima, and E. tenella to identify genotypes/virulence genes associated with infection. 1B. Investigate the molecular mechanisms of virulence associated with co-infection of Eimeria species. 1C. Investigate the effect(s) of host genotypes and environmental interaction that predispose birds to infection with different Eimeria species. 2. Determine the molecular mechanisms of virulence to Clostridium perfringens-based enteritis to inform the development of a safe and effective vaccine. 2A. Sequencing virulent field strains of C. perfringens and identify genotypes/virulent genes associated with gut damage, mortality, and poor performance. 2B. Investigate host genotype and environmental interaction that predispose young birds to C. perfringens-induced enteritis. 2C. Identify and develop vaccine targets and resulting immunological responses to C. perfringens-induced enteritis. 3. Develop alternatives to antibiotics for preventing or treating Eimeria- and C. perfringens-based enteritis. 3A. Investigate the longitudinal impact of site of digestion on microbiota, and host physiological response to Eimeria- and C. perfringens-induced enteritis in commercial birds. 3B. Investigate the mechanistic actions of probiotics and prebiotics as antibiotic alternatives for Eimeria- and C. perfringens-induced enteritis in commercial birds. 3C. 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.
In Objective 1, the team 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. In Objective 2, to better understand the incidence of necrotic enteritis (NE), which is often predisposed by coccidiosis, the team plans to continue collecting field isolates of C. perfringens from the southeast and mid-Atlantic regions for full genome sequencing and comparative analyses of those NE-causing strains. This approach will allow identification of predominant virulence factors in commercial poultry that could serve as targets for designing and developing vaccines as alternative control measures to antibiotics. Using an established nanoparticle vaccine platform, our team 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. For Objective 3, in dealing with the urgent need to identify, test, and employ effective antibiotic alternatives for poultry, our team outlines detailed activities to better understand the mechanistic actions of several candidates 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 these 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.