The association between Mx and BF2 genes on the resistant/supceptible ability for A/H5N1 disease in Vietnamese Mia chickens

Abstract

In the study, 196 Mia chickens were individually challenged by A/H5N1/NCVD-2693-2.3.2.1C sub-strain with the dose of 104 TCID50, and the chicken survival/mortality phenotypes were observed at 28-day post-challenge. The BF2 nucleotide variation in exon 2 was detected by sequencing, and consequently the homologous BF2 haplotypes from 24 individual were identified and grouped into resistant BF2*M-R haplotype and supceptible BF2*M-S haplotype motifs. These motifs were confirmed based on their high nucleotide homology with 26 BF2 haplotypes constructed from 51 haplotypes of White Leghorn and 5 Chinese chicken varieties (Xiayan, BeijingYou, Zhenzu, Wuji, and Sanhuang) published in GenBank. Besides, the Mx genotypes were determined from 196 individuals by PCR-RFLP, using restriction enzyme Hpy8I. The results indicated that the Mx/AA genotype encoding for Asn at pos.631 and BF2*M-R haplotype were identified to be associated with A/ H5N1 resistant trait, while the Mx/GG encoding for Ser and BF2*M-S haplotype expressed to be susceptible. The results also demonstrated that the association between resistant alleles of Mx and BF2 enhanced disease resistibility in chicken.