Reducing the impact of infectious disease on village poultry production in Ethiopia

在包括埃塞俄比亚在内的许多发展中国家，家禽在贫困农村家庭的生计中发挥着重要的经济、营养和社会文化作用，在这些国家，食腐家禽是小农生产系统的一个组成部分，在减轻贫困方面发挥着重要作用。鸡具有很高的社会经济价值，对那些没有牛、羊或山羊的人（通常没有土地）来说很重要。家禽生产对妇女尤其重要，她们通常拥有和管理鸡，并控制销售收入。由此产生的收入通常用于支持儿童的教育。发展中国家有许多本土鸡品种，它们很好地适应了当地环境，因为它们是优秀的觅食者，能够更好地避免捕食者的攻击，并对常见疾病表现出更好的免疫力。然而，由于遗传潜力相对较低和饲养水平较差，这些地方鸡品种大多生长缓慢，生产小尺寸鸡蛋的能力较差。此外，传染病具有重大影响，甚至阻碍了这种有限的遗传潜力的实现。利用当地鸡生态型的育种计划表明，生产力的快速提高是可能的。然而，这些规划尚未选择对传染病的抵抗力。在低投入的家禽生产系统中，通过选择性育种增强遗传抗性是一种未得到充分利用的低成本疾病控制机会。该项目的目的是制定一项家禽育种方案，以提高对重点传染病的抵抗力，同时提高生产力和产量。实现这一目标需要三个进一步重叠的目标：(i)调查当地家禽品种的遗传抗性；（二）确定对乡村家禽造成最大负担的疾病；（三）调查传染病的更广泛的社会和经济影响以及影响采取控制战略的因素。对埃塞俄比亚当地家禽的耐药性进行调查不仅将确定遗传区域和基因，这些遗传区域和基因可用于埃塞俄比亚的杂交育种计划，而且还将极大地扩展我们对家禽耐药性遗传学的认识，迄今为止，这方面的研究主要是在近交系和商业家禽系中进行的。我们确定埃塞俄比亚乡村家禽的重要疾病的研究将是第一个同时检查大量病原体影响的研究，并将开始探索这些病原体如何协同作用以引起农民所看到的疾病。我们还将探讨每年造成许多鸟类死亡的重大流行病的原因。这些知识将使埃塞俄比亚决策者和动物卫生专业人员能够制定更精确的疾病控制规划，并为育种规划的目标提供信息。乡村家禽生产由贫穷的农村农民承担，投入很少或根本没有投入。这意味着所有的产出（蛋、肉、后代）都代表了农民的净收益，但也限制了即使是低成本疾病控制干预措施的潜力。此外，家禽生产深深植根于埃塞俄比亚社会，鸟类的特点对农民很重要。我们将与农民合作，查明影响其禽鸟生产和生产力的疾病、影响采用控制战略（包括本地控制）的因素以及禽鸟的可取特性。我们将利用这些研究结果为正在进行的育种计划的选择提供信息，该计划正在提高当地生态型家禽的生产力，以便向村庄分发。因此，我们将确保改良的禽鸟也增强了对主要传染病的抵抗力。该项目还将提供改善埃塞俄比亚国内能力的遗产，包括培训当地科学家和加强实验室设施。

Poultry play an important economic, nutritional and socio-cultural role in the livelihoods of poor rural households in many developing countries, including Ethiopia, where scavenging poultry are an integrated part of the smallholder production systems and play a significant role in poverty alleviation. Chickens have a high socio-economic value and are important to those (often landless) people who do not own cattle, sheep, or goats. Poultry production is particularly important to women, who often own and manage the chickens and control cash from sales. The resulting income is often used to support education of children. Developing countries have many indigenous chicken varieties which are well adapted to local environments as they are excellent foragers, better able to avoid predator attacks and demonstrate better immunity to common diseases. However, due to relatively low genetic potential and poor levels of husbandry, most of these indigenous chicken breeds grow slowly and are poor producers of small sized eggs. Furthermore, infectious diseases have a major impact and prevent even this limited genetic potential from being realised. Breeding programmes using local chicken ecotypes suggest rapid improvement in productivity is possible. However, these programmes are yet to select for resistance to infectious disease. Enhanced genetic resistance through selective breeding represents an under-exploited low cost opportunity for disease control in low input poultry production systems. The aim of this project is to develop a poultry breeding programme to improve resistance to priority infectious diseases whilst enhancing productivity and production. Realisation of this objective requires three further overlapping objectives: (i) investigation of the genetic resistance of local poultry varieties; (ii) identification of the diseases with the greatest burden to village poultry; and, (iii) investigation of the wider social and economic impact of infectious diseases and of factors affecting uptake of control strategies. Investigation of resistance in local Ethiopian poultry will not only identify genetic regions and genes that can be used to inform cross breeding programmes in Ethiopia, but will also greatly extend our knowledge of the genetics of resistance in poultry, which to date has largely been studied in inbred and commercial poultry lines. Our study identifying the important diseases of village poultry in Ethiopia will be the first to simultaneously examine the impact of a large number of pathogens and will begin to explore how these agents act in concert to cause the diseases seen by farmers. We will also explore the cause of the major epidemics seen each year resulting in death of many birds. Together, this knowledge will enable more precise disease control planning by Ethiopian policy makers and animal health professionals, as well as inform targeting of the breeding programme. Village poultry production is undertaken by poor rural farmers with little or no input. This means that all output (eggs, meat, offspring) represent a net gain to the farmer, but also limits the potential for even low cost disease control interventions. Furthermore, poultry production is deeply imbedded in Ethiopian society and the characteristics of birds are important to the farmers. We will work with farmers to identify diseases impacting production and productivity of their birds, factors affecting uptake of control strategies (including indigenous controls) and the desirable characteristics of birds. We will utilise the results of these studies to inform selection in an ongoing breeding program which is improving the productivity of local poultry ecotypes for distribution to villages. Thus we will ensure that the improved birds also have enhanced resistance to key infectious diseases. The project will also provide a legacy of improved capacity within Ethiopia, including training of local scientists and enhanced laboratory facilities.