Genetic Analysis of a Commercial Egg Laying Line Challenged With Newcastle Disease Virus

Abstract

In low income countries, chickens play a vital role in daily life. They provide a critical source of protein through egg production and meat. Newcastle disease, caused by avian paramyxovirus type 1, has been ranked as the most devastating disease for scavenging chickens in Africa and Asia. High mortality among flocks infected with velogenic strains leads to a devastating loss of dietary protein and buying power for rural households. Improving the genetic resistance of chickens to Newcastle Disease virus (NDV), in addition to vaccination, is a practical target for improvement of poultry production in low income countries. Because response to NDV has a component of genetic control, it can be influenced through selective breeding. Adding genomic information to a breeding program can increase the amount of genetic progress per generation. In this study, we challenged a commercial egg-laying line with a lentogenic strain of NDV, measured phenotypic responses, collected genotypes, and associated genotypes with phenotypes. Collected phenotypes included viral load at 2 and 6 days post-infection (dpi), antibody levels pre-challenge and 10 dpi, and growth rates pre- and post-challenge. Six suggestive QTL associated with response to NDV and/or growth were identified, including novel and known QTL confirming previously reported associations with related traits. Additionally, previous RNA-seq analysis provided support for several of the genes located in or near the identified QTL. Considering the trend of negative genetic correlation between antibody and Newcastle Disease tolerance (growth under disease) and estimates of moderate to high heritability, we provide evidence that these NDV response traits can be influenced through selective breeding. Producing chickens that perform favorably in challenging environments will ultimately increase the supply of quality protein for human consumption.

Genetic responses of inbred chicken lines illustrate importance of eIF2 family and immune-related genes in resistance to Newcastle disease virus

“…The severity of infection with NDV is determined by many different factors such as tissue tropism, efficiency of replication, concurrent diseases, and host resistance to the virus 26 . Some of the NDV response traits are known to have a component of genetic control 27 . Gene expression changes in the immune response to the NDV challenge in two highly inbred lines and their sublines, the Fayoumi (M5.…”

Genome-Wide Association Study to Identify SNPs and Haplotypes Associated with Reproductive Performance and Egg Quality Traits in Geese

“…Sichuan White is a popular Chinese goose breed reared for both meat and eggs. While egg laying and egg quality traits have been studied intensively in avians, including chickens [29,30], ducks [15,31], and quail [32], few studies have examined traits other than those associated with egg laying in the goose genome [13].…”

Association of Candidate Genes with Response to Heat and Newcastle Disease Virus

“…Body weights were recorded on days 0, 21, and 31 of age. Previously, two distinct genome wide association studies (GWAS) (NDV and heat + NDV) associated 600 k genotypes from these birds with the NDV viral load, anti-NDV antibody, and growth rate phenotypes described herein [ 35 , 36 ].…”

“…Heritabilities for anti-NDV antibody level at 10 dpi, ND viral load at 2 and 6 dpi, and pre and post NDV challenge growth rate were estimated across both treatment groups. Heritabilities for these NDV challenge related phenotypes were previously estimated for the treatment groups separately and were reported in [ 35 , 36 ]. For heat challenge related phenotypes, heritability was estimated among the heat challenged animals only [ 41 ].…”

“…Room and replicate were treated as distinct between treatments so that the RR effect captured treatment effects as well. Random effects included animal genetic effects (A) with a genomic relationship matrix that were computed using genotypes of 338,814 quality-controlled SNPs from the 600 K SNP panel [ 35 , 36 ] for 946 animals following the procedure described by [ 43 ], and residuals (e). The random effect of dam was included for pre-challenge measurements of growth rate.…”