An Integrated Basic and Translational Approach to Mitigate Key Enteric Diseases of Poultry

The objectives of this project are to:

1. Investigate the mechanisms of pathogenicity of Eimeria field isolates that cause poultry coccidiosis and assess the bird responses to infections. The team will (1) propagate and harvest pure cultures of Eimeria isolates to obtain high quality DNA for generating full genome sequences of Eimeria parasites; (2) test the ability of divergent isolates to induce coccidiosis in commercial birds and measure the differential responses to individual and mixed infections; and (3) study the influence of host genetics on resistance, susceptibility, and tolerance to field Eimeria isolates, in combination with defined environmental conditions that influence the birds’ microbiome and intestinal integrity leading to pathological status and pre-disposition to secondary infections.

2. Identify and characterize the molecular mechanisms of Clostridium perfringens infections resulting in necrotic enteritis and develop effective vaccines. The team will (1) employ next-generation sequencing to fully characterize the genomes of C. perfringens isolates (collected from field cases in the Southeast and mid-Atlantic regions) causing necrotic enteritis and comparatively analyze those sequences to identify virulence factors that contribute to the development of clinical and subclinical enteritis; this will allow a better understanding of the incidence of necrotic enteritis in the context of coccidiosis in commercial poultry; (2) test the effects of those isolates on the pathological and immunological responses of chickens with divergent genetic backgrounds, which could further delineate the differential responses in commercial chicken breeds to aid in identifying and using species genetics in commercial operations; (3) use the identified virulence factors as targets for designing and developing vaccines (based on already established nanoparticle platforms) as alternative measures to antibiotics for controlling enteritis.

3. Test and determine effective non-drug alternatives to antibiotics for the prevention and treatment of coccidiosis and necrotic enteritis. For Objective 3, there is an impetus to find effective non-drug alternatives, and the team will employ an integrated approach involving applied studies to better understand the mechanistic actions of several alternative candidates on performance, physiological, microbial, immunological, and metabolic responses of the host. In vivo (birds) and in ovo (late-stage embryos) trials will investigate the applications of well-defined probiotics, prebiotics, postbiotics, and phytogenics during coccidiosis and necrotic enteritis to characterize these critical physiological changes that directly impact bird health and performance. Specific measurable variables at the enteric and systemic levels will collectively provide strong host response correlates that can be utilized in translational studies to refine the applications of such effective alternatives in commercial settings.

Funder: USDA ARS

Amount: $728,944

PI: Todd Applegate, College of Agricultural and Environmental Sciences