Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA 50011, USA.
Department of Veterinary Medicine and Public Health, Sokoine University, P.O. Box 3000 Chuo Kikuu, Morogoro, Tanzania.
Genes (Basel). 2019 Jul 17;10(7):546. doi: 10.3390/genes10070546.
Newcastle Disease (ND) is a continuing global threat to domestic poultry, especially in developing countries, where severe outbreaks of velogenic ND virus (NDV) often cause major economic losses to households. Local chickens are of great importance to rural family livelihoods through provision of high-quality protein. To investigate the genetic basis of host response to NDV, three popular Tanzanian chicken ecotypes (regional populations) were challenged with a lentogenic (vaccine) strain of NDV at 28 days of age. Various host response phenotypes, including anti-NDV antibody levels (pre-infection and 10 days post-infection, dpi), and viral load (2 and 6 dpi) were measured, in addition to growth rate. We estimated genetic parameters and conducted genome-wide association study analyses by genotyping 1399 chickens using the Affymetrix 600K chicken SNP chip. Estimates of heritability of the evaluated traits were moderate (0.18-0.35). Five quantitative trait loci (QTL) associated with growth and/or response to NDV were identified by single-SNP analyses, with some regions explaining ≥1% of genetic variance based on the Bayes-B method. Immune related genes, such as ETS1, TIRAP, and KIRREL3, were located in regions associated with viral load at 6 dpi. The moderate estimates of heritability and identified QTL indicate that NDV response traits may be improved through selective breeding of chickens to enhance increased NDV resistance and vaccine efficacy in Tanzanian local ecotypes.
新城疫（ND）是全球范围内对家禽的持续威胁，尤其是在发展中国家，那里强毒力 ND 病毒（NDV）的严重爆发经常给家庭带来重大经济损失。本地鸡通过提供高质量蛋白质，对农村家庭生计非常重要。为了研究宿主对 NDV 反应的遗传基础，在 28 日龄时，用一种低致病性（疫苗）NDV 株对三个坦桑尼亚流行的鸡生态型（区域种群）进行了挑战。除了生长速度外，还测量了各种宿主反应表型，包括抗 NDV 抗体水平（感染前和感染后 10 天，dpi）和病毒载量（2 和 6 dpi）。我们通过对 1399 只鸡进行基因分型，使用 Affymetrix 600K 鸡 SNP 芯片，估计了遗传参数并进行了全基因组关联研究分析。所评估性状的遗传力估计值适中（0.18-0.35）。通过单 SNP 分析鉴定了与生长和/或对 NDV 反应相关的五个数量性状基因座（QTL），其中一些区域根据贝叶斯-B 方法解释了≥1%的遗传方差。免疫相关基因，如 ETS1、TIRAP 和 KIRREL3，位于与 6 dpi 时病毒载量相关的区域。中等遗传力估计值和鉴定的 QTL 表明，通过对坦桑尼亚本地生态型鸡进行选择性繁殖，可改善 NDV 反应性状，以增强对 NDV 的抗性和疫苗效力。
