Submitted to: Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/1/2009
Publication Date: 11/15/2009
Citation: Kim, D., Kim, C., Lillehoj, H.S., Lamont, S. 2009. Gene expression profiles of two B-complex disparate, genetically inbed Fayoumi chicken lines that differ in suceptibility to Eimeria maxima. Poultry Science. 88:1565-1579. Interpretive Summary: Avian coccidiosis is caused by infection with protozoa and impairs the poultry industry by its detrimental influence on production efficiency such as survivability, nutrient absorption, growth rate, and egg production. Until now, disease control strategies against avian coccidiosis have mostly depended on prophylactic chemotherapy and vaccination, but both methods have serious drawbacks. Genetic selection for disease resistance and immune responses can lead to a reduction of drug use and risk of vaccination in commercial poultry production. However, information about the chicken immune system at the molecular level is very limited. In this paper, ARS scientists report new findings that shed lights on how genetics play a role in controlling disease resistance against poultry coccidiosis. Using new functional genomics technology which allows detecting differential gene expression patterns of more than 10,000 genes from chicken intestine, these researchers compared two genetically different chicken lines which show different coccidiosis resistance. Transcriptional profiling revealed differential expression of genes possessing various functional roles including immunity and defense between two B-complex disparate, genetically inbred chicken lines after Eimeria infection. The results will enhance our ability to manipulate genetics of poultry to enhance their disease resistance against coccidiosis, and will eventually facilitate the development of marker-assisted selection strategy for coccidiosis-resistant chickens.
Technical Abstract: This study was conducted to compare the gene expression profiles following Eimeria maxima infection between two B-complex congenic lines (lines M5.1 and M15.2) of Fayoumi chickens which display differences in disease resistance and innate immunity against avian coccidiosis. A cDNA microarray, constructed from 10,162 elements including 9,668 EST of chicken intestinal intraepithelial lymphocytes (IEL), was used to compare the transcript levels in IELs of the M5.1 and M15.2 lines from uninfected and E. maxima infected birds. When compared to uninfected controls and using a cutoff of > 2.0-fold alteration (P < 0.05), M5.1 demonstrated altered expression of 1 (down-regulated), 12 (6 up, 6 down), and 18 (5 up, 13 down) mRNAs at 3, 4, and 5 days post-infection, respectively. In the M15.2 line, altered expression was observed in 6 (3 up, 3 down), 29 (11 up, 18 down), and 32 (8 up, 24 down) transcripts at the 3 time points, compared with uninfected controls. Comparison of the expression levels between M5.1 and M15.2 chickens following E. maxima infection revealed alterations in 32 (10 up, 22 down), 98 (43 up, 55 down), and 92 (33 up, 59 down) mRNAs at the 3 time points. Functional analysis using Gene Ontology categorized the genes exhibiting the different expression patterns between two chicken lines into several GO terms including immunity and defense. In summary, transcriptional profiles showed that more gene expression changes occurred with E. maxima infection in the M15.2 than the M5.1 line. The most gene expression differences between the two chicken lines were exhibited at days 4 and 5 following E. maxima infection. The results of this study are a foundation of future studies to comprehend the innate immune system in the chicken gut and develop the strategy against avian coccidiosis.