Association of the toll-like receptor 4 and Myxovirus genes with resistance to Salmonella and Newcastle disease in selected Sentul chickens

Abstract

Toll-like receptor 4 and myxovirus genes have been demonstrated to confer resistance to Salmonella and Newcastle disease (ND), respectively. These genes have not yet been investigated in Sentul chickens. Therefore, the aim of this study was to determine the polymorphisms and association of the TLR4 and Mx genes as candidate genes underlying resistance to Salmonella and ND in selected Sentul chickens. One hundred and eighty-five Sentul chickens were genotyped using PCR-RFLP. The genotype and allele frequencies, polymorphic information contents and Hardy-Weinberg equilibrium (HWE) statuses were analysed. The genotypes were associated with immunoglobulin Y (IgY), Salmonella-specific antibodies and Newcastle disease-specific antibodies. These parameters were determined using indirect ELISA, clearance tests and haemagglutination inhibition, respectively. The immune traits were further grouped into high, medium and low categories. The data were analysed using the GLM and t-test. Polymorphisms in TLR4|MscI and Mx|Hpy8I were observed. The population was in HWE for both genes. The frequencies of the TLR4 allele G and genotype GG were significantly high (P<0.05) in chickens with high immune traits. The genotype GG of TLR4 gene recorded significantly higher immune traits than genotypes AA and AG. For the Mx gene, the frequency of allele A was higher than of allele G at a high IgY titre. TLR4|MscI and Mx|Hpy8I are potential markers for selection against Salmonella and Newcastle disease in Sentul chickens. However, further investigations are recommended.