Genomic markers associated with immune traits in Sasso chickens raised in Ethiopia

Abstract

Newcastle disease virus (NDV) is one of the highly contagious avian pathogens that threaten poultry producers based in endemic zones as a result of its epidemic potential. Selection for antibody (Ab) response has potential to effectively improve the resistance of disease in chickens. However, the molecular basis of the variation among chickens in Ab response to NDV remains unclear. This study aimed to identify the genes modulating Ab response to a viral pathogen such as NDV while under outdoor conditions. A genome-wide association study (GWAS) was conducted on Sasso T451A chickens that were naturally exposed to infectious diseases to identify regions associated with Ab response to NDV. Phenotypic and immune data from 1022 chickens in two batches (507 in batch four and 515 in batch five) and genotyping from 935 chickens (2,676,181 single nucleotide polymorphisms(SNP)) were used for association analysis. BioMart data mining as well as variant effect predictor tools were used to annotate SNPs and candidate genes, respectively. The results revealed that batch four compared to batch five chickens showed a stronger Ab response at 56 days and lower Ab response at 112 days old. A total of five significant SNPs (rs733628728, rs316795557 (FOXP2), rs313761644 (CEP170B) and two unnamed) were significantly (p <3.92E-7) associated with chicken antibody response to ND. These SNPs present on chromosomes 1, 5 and 13, are in genomes regions including several genes with roles in the regulation of the immune response. The results of this study pave the path for more investigation into the host immune response to NDV.