Date: Saturday, January 14, 2012
Time: 4:40 PM
Time: 4:40 PM
Infection with avian pathogenic Escherichia coli (APEC) causes significant losses in poultry production. Enhanced innate resistance to APEC is a sustainable method to improve animal health and food safety and to reduce reliance on antibiotics. A greater understanding of the genetics of the host response to bacteria is required to develop effective genetic selection programs for improved resistance. Our comprehensive study examined the transcriptomic response of broilers to challenge with APEC, with or without prior vaccination. The birds in the unvaccinated, APEC-challenged group were also categorized by lesion scores, to give insight into genetic mechanisms that differentiate resistance from susceptibility to pathology. A 44K Agilent global microarray was used to measure gene expression in two tissues, spleen and peripheral blood leukocytes (PBL), from the same 40 birds. Birds showing severe pathology had a greater induction of gene response than repression. DAVID analysis identified many terms related to immune response and metabolic processes. In addition to the differentially expressed genes and networks identified in individual tissues, the combined bi-analysis of two tissues from the same birds gave insights into potential systemic signaling between tissues. High concordance in the direction of treatment-related differential expression was detected. Comparison of cross-tissue and cross-time data implicated early enrichment in MAPK expression in PBL with later, downstream activation of cytokines and their receptors in spleen. Studying transcriptomes of multiple, relevant immune tissues in the context of pathogen challenge facilitates gaining a more comprehensive understanding of the genomics of host systemic response.