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The poultry industry suffers major economic losses from both mortality due to infectious diseases and potential contamination of food products due to transfer of microorganisms. As a result, breeder companies have a keen interest in identifying chickens capable of resisting infection by microorganisms. Our laboratory focuses on evaluating the innate immune system of commercial broilers in order to assess their capacity to protect against pathogenic invasion. <P>The objective of this research is to employ a functional genomics approach to develop a novel selection method to identify poultry with increased resistance to diverse pathogens, including, but not limited to, Salmonella. Through this work, we will provide poultry breeders with a novel tool by which to rate potential lines of chickens and specific individuals within the line, and their ability to resist infections. These data will equip breeder companies with a means to objectively select individual broilers to use as parental stock.
Approach: Identify high and low responders (both hens and roosters) within a population of broilers using an oligonucleotide microarray and quantitative real-time RT-PCR. Blood (6-8 ml) will be collected from line B chickens (n=200) at 6-10 weeks post-hatch. Total RNA will be extracted from heterophils and monocytes and evaluated using the custom innate-immune-specific oligonucleotide microarray according to standard methodologies and the data analyzed using analysis software. The microarray data will be confirmed using real-time quantitative RT-PCR. The microarray and real-time quantitative RT-PCR data will be used to identify individual chickens with high and low innate immune gene profiles. Following the initial genomic analyses, specific matings utilizing the 200 characterized birds will be arranged when the birds are 26 weeks of age. Roosters with low innate responses will be mated to high hens and the reciprocal matings of high roosters to low hens will be carried out. Fertile eggs will be collected daily, incubated, and hatched under standard conditions. The innate immune gene profile of the pedigreed progeny will be characterized at 6-10 weeks of age utilizing the microarray and quantitative real-time RT-PCR. This will allow us to determine if the innate immunity gene profile is controlled / influenced by the rooster or hen and if the high parent profile is a dominant trait that can be selected for over the low profile. Based on the data obtained, we will determine if selection based on the innate immune responsiveness is a novel method to identify chickens with increased resistance to bacterial infections.