Association of resistance to avian coccidiosis with single nucleotide polymorphisms in the zyxin gene

Our previous genetic studies demonstrated that resistance to avian coccidiosis is linked with micro-satellite markers LEI0071 and LEI0101 on chromosome 1. In this study, the associations between parameters of resistance to coccidiosis and single nucleotide poly-morphisms (SNP) in 3 candidate genes located between LEI0071 and LEI0101 [zyxin, CD4, and tumor necrosis factor receptor super family 1A (TNFRSF1A)] were de-termined. The SNP were genotyped in 24 F₁ generation and 290 F₂ generation animals. No SNP were identified in the TNFRSF1A gene, whereas 10 were located in the zyxin gene and 4 in the CD4 gene. At various times following experimental infection of the F₂ generation with Eimeria maxima, BW, fecal oocyst shedding, and plasma levels of carotenoid, nitrite plus nitrate (NO_2- + NO_3-), and interferon-γ (IFN-γ) were measured as parameters of resistance. Single marker and haplotype-based tests were applied to determine the associations between the 14 SNP and the parameters of coccidiosis resistance. None of the CD4 SNP were correlated with disease resistance. However, by single marker association, several of the zyxin SNP were significantly associated with carotenoid or NO₂^- + NO₃^- concentrations. These were the SNP at nucleotide 149 associated with carotenoid at d 3 postinfection (PI), nucleotide 187 with carotenoid at d 6 and 9 PI, and nucleotide 159 with carotenoid between d 3 and 9 PI. In addition, the zyxin SNP at nucleotide 191 was significantly associated with increased levels of NO₂^- + NO₃^- at d 3 PI. By haplotype association, the zyxin SNP also were found to be highly associated with NO₂^- + NO₃^- at d 3 PI and increased IFN-γ at d 6 PI. These results suggest that zyxin is a candidate gene potentially associated with increased resistance to experimental avian coccidiosis.