Genetic effects analysis of myeloid leukemia factor 2 and T cell receptor-beta on resistance to coccidiosis in chickens.

Associations between the parameters of resistance to coccidiosis and SNP in 3 candidate genes located on chromosome 1 [T cell receptor-beta (TCR-beta), myeloid leukemia factor 2 (MLF2), and lymphotactin] were determined. Single nucleotide polymorphisms were genotyped in 24 F1 generation and 290 F2 generation birds. Four SNP were identified in the lymphotactin gene, 12 were located in the TCR-beta gene, and 4 in the MLF2 gene. At various times after experimental infection of the F2 generation with Eimeria maxima, BW, fecal oocyst shedding, and biochemical parameters were measured as parameters of coccidiosis resistance. Single marker association test was applied to determine the associations between the 20 SNP and the parameters of coccidiosis resistance. The maximum additive genetic effect on disease resistance of an SNP in MLF2 was explained by BW (P = 0.0002). The SNP in MLF2 significantly associated with BW was also associated with fecal oocyst shedding (P = 0.001). Four SNP associated with oocyst shedding were found within the coding region of TCR-beta (P < 0.05). Although none of the lymphotactin SNP were associated with oocyst shedding, interferon-gamma level was associated with 2 SNP in lymphotactin. These results suggest that the SNP in the MLF2 gene can be one of the markers to select coccidiosis resistance in chickens.