Location: Avian Disease and Oncology ResearchTitle: Single nucleotide polymorphism variants within tva and tvb receptor genes in Chinese chickens) Author
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2014
Publication Date: 8/14/2014
Citation: Lao, C., Chen, S., Chen, W., Liu, Y., Sun, B., Li, H., Zhang, H., Qu, H., Wang, J., Shu, D., Xie, Q. 2014. Single nucleotide polymorphism variants within tva and tvb receptor genes in Chinese chickens. Poultry Science. 93(10): 2482-2489. DOI: 10.3382/PS.2014-04077. Interpretive Summary: Avian leukosis, an infectious disease of poultry caused by avian sarcoma leucosis viruses, remains an ongoing problem worldwide. As such, it forces the industry to monitor prevention measures and causes complications in international trade of poultry products. This study investigated 10 Chinese local breeds and 15 commercial broiler lines on genetic makeups that determine resistance and susceptibility to avian leucosis virus infection. The findings of this study provide fundamental parameters that should help formulate plans for the genetic improvement of disease resistance, thus, alleviate issues of animal welfare and associated costs.
Technical Abstract: Avian leukosis is an immunosuppressive neoplastic disease caused by avian leukosis viruses (ALV), which causes tremendous economic losses in the worldwide poultry industry. The susceptibility or resistance of chicken cells to subgroup A ALV and subgroup B, D, and E ALV are determined by the receptor genes tumor virus locus A (tva) and tumor virus locus B (tvb), respectively. Four genetic resistant loci (tvar1, tvar2, tvar3, and tvar4) in tva receptor gene and a genetic resistant locus tvbr in the tvb receptor gene have been identified in inbred lines of White Leghorn. To evaluate the genetic resistance to subgroup A, B, D, and E ALV, genetic variations within resistant loci in tva and tvb genes were screened in Chinese local chicken breeds and commercial broiler lines. Here, the heterozygote tvas1/r1 and the resistant genotype tvar2/r2, tvar3/r3, and tvar4/r4 were detected in Chinese chickens by direct sequencing. The heterozygote tvas1/r1 was detected in Huiyang Bearded chicken (HYBC), Rizhaoma chicken, and commercial broiler line 13 to 15 (CB13 to CB15), with the frequencies at 0.08, 0.18, 0.17, 0.25, and 0.15, respectively. The resistant genotype tvar2/r2 was detected in Jiningbairi chicken (JNBRC), HYBC, and CB15, with the frequencies at 0.03, 0.08, and 0.06, respectively, whereas tvar3/r3 and tvar4/r4 were detected in 19 and 17 of the 25 Chinese chickens tested, with the average frequencies at 0.13 and 0.20, respectively. Furthermore, the resistant genotype tvbr/r was detected in JNBRC, CB07, CB12, CB14, and CB15 by pyrosequencing assay, with the frequencies at 0.03, 0.03, 0.11, 0.09, and 0.15, respectively. These results demonstrated that the potential for genetic improvement of resistance to subgroup A, B, D, and E ALV were great both in Chinese local chickens and commercial broilers. This study provides valuable insight into the selective breeding for chickens genetically resistant to ALV.