Submitted to: Avian Immunology Group Meeting
Publication Type: Abstract Only
Publication Acceptance Date: April 30, 2004
Publication Date: May 1, 2004
Citation: Lillehoj, H.S., Min, W., Zhu, J., Emara, M. 2004. Fine mapping of quantitative trait loci (qtl) which control disease resistance to eimeria infection.. Avian Immunology Group Meeting, p. 22.
Avian coccidiosis is caused by several Eimeria strains which infect different regions of the intestine inducing a strain-specific immunity. Parasitic infections usually stimulate a number of immunological defense mechanisms, namely both antibody- and cell-mediated. The particular effect of the response depends upon the specific parasite and stage of infection. To map QTL associated with disease resistance to avian coccidiosis and growth, two commercial broiler lines with different degrees of resistance to the disease were crossed to generate F1 generation that were intercrossed to produce 314 F2 generation offspring. The F2 offspring were inoculated with sporulated oocysts of Eimeria maxima. Five disease-associated phenotypes were measured after the infection. Inter-trait comparisons revealed that oocyst shedding was a good parameter for evaluating disease resistance or susceptibility. One hundred and nineteen microsatellite markers, covering 80 % of the chicken genome with an average marker interval of 25 cM, were used for genotyping of F1 parents and F2 offspring. Statistical analysis based on the data of four families revealed a locus on Chromosome 1 associated with oocyst shedding (logarithm of odds = 3.46). The genetic mechanism of this locus appeared additive. The genomic scan also identified three potential growth QTL on Chromosomes 1, 6, and 8. These results provide the foundation for further investigation to validate the QTL.