1a.Objectives (from AD-416):
Develop DNA markers associated with causative pathogens of necrotic enteritis.
1b.Approach (from AD-416):
DNA markers will be identified first by analyzing genetic differences of disease resistance difference in NE between two genetic lines of poultry; second by analyzing transcriptional profiling based on gene microarray and RNA sequencing, SNP genotyping of NE-related markers using SNP array; and finally validating NE-associated biomarkers in commercial chickens.
The increasing trends of legislative restrictions and voluntary removal of antibiotic growth promoters worldwide has already impacted, and will continue to affect, poultry production and animal health. Necrotic enteritis (NE) is being considered among the most important infectious diseases in the current poultry production system globally, with estimated annual economic loss of more than $2 billion largely due to medical treatments and impaired growth performance. Thus, there is an urgent need to develop rational, alternative, and integrated management strategies not only to control, but also to prevent NE. In order to accomplish these goals, a better understanding of host genetic factors on the development of NE will be necessary. Furthermore, a reliable and reproducible NE disease model is needed for characterization of Clostridium perfringens pathogenesis and host protective immunity. During this first year, we have established an experimental NE disease challenge model in commercial meat-type birds using Eimeria maxima and C. perfringens. In order to investigate the effects of host genetics on NE susceptibility, we evaluated two chicken lines for NE susceptibility in collaboration with ARS's Avian Diseases and Oncology Laboratory. In the first large-scale experiments, using 100 birds per line, we were able to show significant differences between the two lines with respect to NE susceptibility.