FUNCTIONAL GENOMICS AND GENETIC ANALYSIS OF THE INNATE IMMUNE RESPONSE REQUIRED TO RESIST FOOD-BORNE BACTERIAL INFECTIONS IN POULTRY
Location: Food and Feed Safety Research
Title: Caecal transcriptome analysis of colonized and non-colonized chickens within two genetic lines that differ in caecal colonization by Campylobacter jejuni
Research conducted cooperatively with:
Submitted to: Animal Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 4, 2010
Publication Date: September 25, 2011
Citation: Li, X., Swaggerty, C.L., Kogut, M.H., Chiang, H., Wang, Y., Genovese, K.J., He, L.H., Pevzner, I.Y., Zhou, H. 2011. Caecal transcriptome analysis of colonized and non-colonized chickens within two genetic lines that differ in caecal colonization by Campylobacter jejuni. Animal Genetics. 42:491-500.
Interpretive Summary: Campylobacter jejuni (C. jejuni) is one of the most common causes of food-borne illness in the world, and poultry products are one of the main sources of contamination. How chickens respond to a C. jejuni infection is not known. Previously, we showed that two different lines of chickens (line A and B) responded differently to a C. jejuni infection; line A was more resistant and line B was more susceptible to the bug. In our previous study, we found that not all baby chicks became infected with the bug, so we wanted to know why certain chickens became infected while others did not. In the present study, to profile the response to C. jejuni infection in baby chickens, a piece of intestine was removed and analyzed using a molecular biology tool known as microarray analysis. We found genes associated with specific signaling pathways mainly contribute to the differences between a baby chicken getting infected or not by C. jejuni. The results from this study showed us specific genes that were associated with resistance against C. jejuni infections in chickens. If we can utilize more resistant chickens in the food chain, there will be a reduced risk to the consumer and the food supply will be safer.
Campylobacter jejuni (C. jejuni) is one of the most common causes of human bacterial enteritis worldwide. The molecular mechanisms of the host responses of chickens to C. jejuni colonization have not been well understood. We have previously shown differences in C. jejuni colonization at 7 days post-inoculation (pi) between two genetic broiler lines. However, within each line, not all birds were colonized by C. jejuni (27.5% colonized in line A and 70% colonized in line B). Therefore, the objective of the present experiments was to further define the differences in host gene expression between colonized and non-colonized chickens within each genetic line. RNA isolated from ceca of colonized and non-colonized birds within each line was applied to a chicken 44K Agilent microarray for pair-comparison. The data indicates that inhibition of small GTPase-mediated signal transduction could enhance the resistance to C. jejuni colonization and that the tumor necrosis factor receptor superfamily genes play important roles in determining C. jejuni non-colonization in broilers. Our study supports MAPK pathway is important in host response to C. jejuni colonization in line B, but not line A. There was a difference in the mechanisms of host resistant to C. jejuni colonization between line A and line B. Ten times more differentially expressed genes were observed between colonized and non-colonized chickens within line B than those within line A.