Serum IL10 provides separable resistance and tolerance traits in chicken response to coccidiosis

While breeding for resistance to Eimeria spp. ( the cause of coccidiosis in chickens), offers one route to mitigation of their impacts on production, tolerance to the disease may be less desirable, with potential impacts on disease transmission and welfare. In a large-scale study seeking evidence of selectable variance in response to coccidiosis, correlations were found between IL10 (serum interleukin-10, an anti-inflammatory cytokine) and intestinal damage. Eigen analysis to dissect the relationships between these variables the production trait, weight gain, produced three distinct vectors. Visualisation of the Eigenvectors confirmed the separation of resistant and susceptible chickens, with both producing high levels of IL10. A third, tolerant subpopulation produced little or no IL10. A GWAS uncovered novel suggestive genome-wide significant SNPs for the three measured traits, although the proprietary 62K SNP array (Cobb-Vantress) used did not cover the location of the chicken IL10 gene. However, SNPs relating to IL10 were located in the region of IL10R2 on the chicken genome. Upregulation of this gene is essential for the production of IL10 in innate immune response to infection. To further investigate, WGS data obtained from > 20 broilers and layers are being compared with the Red Jungle Fowl genome to locate selective sweeps for this and other IL10 receptors, plus the IL10 gene itself, to identify mutations in these genes that may relate to disease tolerance.