Rowland Kaylee, Wolc Anna, Gallardo Rodrigo A, Kelly Terra, Zhou Huaijun, Dekkers Jack C M, Lamont Susan J
Department of Animal Science, Iowa State University, Ames, IA, United States.
Hy-Line International, Dallas Center, IA, United States.
Front Genet. 2018 Aug 20;9:326. doi: 10.3389/fgene.2018.00326. eCollection 2018.
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.
在低收入国家，鸡在日常生活中发挥着至关重要的作用。它们通过产蛋和提供肉类，成为蛋白质的重要来源。由1型禽副粘病毒引起的新城疫，被列为非洲和亚洲散养鸡最具毁灭性的疾病。感染速发型毒株的鸡群死亡率很高，给农村家庭造成了饮食蛋白质和购买力的巨大损失。除了接种疫苗外，提高鸡对新城疫病毒（NDV）的遗传抗性，是低收入国家提高家禽产量的一个切实可行的目标。由于对NDV的反应有遗传控制的成分，因此可以通过选择性育种来加以影响。在育种计划中加入基因组信息，可以增加每一代的遗传进展量。在本研究中，我们用一株弱毒株新城疫病毒攻击一个商业蛋鸡品系，测量表型反应，收集基因型，并将基因型与表型关联起来。收集的表型包括感染后2天和6天的病毒载量、攻毒前和攻毒后10天的抗体水平，以及攻毒前后的生长率。鉴定出6个与对NDV的反应和/或生长相关的暗示性QTL，包括新的和已知的QTL，证实了先前报道的与相关性状的关联。此外，先前的RNA测序分析为位于已鉴定QTL内或附近的几个基因提供了支持。考虑到抗体与新城疫耐受性（疾病状态下的生长）之间的负遗传相关趋势以及中到高遗传力的估计，我们提供证据表明，这些对NDV的反应性状可以通过选择性育种来影响。培育出在具有挑战性的环境中表现良好的鸡，最终将增加供人类食用的优质蛋白质的供应。
