ROBUST-SMOLT Impact of early life history in freshwater Recirculation Aquaculture Systems on A. salmon robustness and susceptibility to disease at sea

通过采用新的养殖技术（陆基循环水养殖系统）和控制动物生理的养殖制度，全球大西洋鲑鱼产业得以迅速扩大。这包括parr-smolt转化（鲑鱼变得耐海水的过程）和早熟，影响鱼类福利和产品质量。英国的鲑鱼生产商要么已经建成，要么正在建设这样的大型生产设施。与陆基或开放水域湖泊系统相比，这些系统具有明显的优势，包括减少用水量、改善废物管理、更好地控制疾病以及能够操纵全年鲑鱼生产的环境条件。然而，近年来，关于这些鱼在开放海水网箱中暴露于具有挑战性的自然条件下的健壮性的问题已经出现，特别是对于鳃病变和一种新的贫血综合征。尽管行业和政府对鲑鱼行业的增长抱有强烈愿望，以满足日益增长的市场需求，但养殖公司正面临相当大的压力，近年来产量至多停滞不前，甚至自2015年以来有所下降。这主要是由于海上鱼类健康面临挑战，导致紧急捕捞和海上不可持续的损失。从过去4年联盟研究小组获得的结果来看，很明显，鱼类在淡水发育早期所经历的条件会影响它们在海上的长期表现和健壮性。目前的项目旨在描述淡水环境条件（包括RAS和开放水域湖泊系统之间的水化学、温度、光周期和营养）对鱼类性能和整体健康的影响。该项目测试的主要假设是，在淡水RAS中生产的鲑鱼的早期生活史会影响免疫屏障（主要是鳃、肠道和皮肤），这可能使鱼类在海上易患鳃病。该项目将研究RAS微生物群（如生活在鱼肠、鳃和皮肤中的微生物种群）和水化学（特别是二氧化碳）如何影响鱼的免疫功能和性能。环境制度（光周期、温度和饮食）的改变以及在海上对特定疾病提供主动保护的疫苗的影响，将在转移到海上后对幼鱼的免疫功能、性能和健康进行测试。最后，将研究淡水RAS中的鱼类发育及其对商业性能和整体健康的影响之间的关系，包括鱼类基因组成的影响、新贫血综合征的特征和大规模流行病学研究。为了确保项目的成功，该联盟汇集了来自英国四家主要研究机构的世界顶尖科学家，他们致力于水产养殖和可持续畜牧业发展，并与四家领先的鲑鱼养殖、饲料制造和制药公司合作。该项目还得到了政府研究中心和行业领导组织的大力支持。这项研究将有助于开发生产高质量鲑鱼的实用方法，有利于动物福利和该行业的可持续性和盈利能力。由于养殖鲑鱼是英国饮食中的主要食物来源，每天食用的鲑鱼超过120万份，因此该项目对英国人口的健康和福祉也具有重要意义。通过支持鲑鱼养殖业的可持续发展，该项目将有助于保护苏格兰大部分农村地区的9000多个直接就业和与行业相关的工作岗位，并有助于创造新的就业机会。

The rapid expansion of the global Atlantic salmon industry has been made possible through the adoption of new farming technologies (land based Recirculating Aquaculture Systems, RAS) and husbandry regimes to manipulate animal physiology. This includes the parr-smolt transformation (the process by which salmon become seawater tolerant) and early maturation impacting on fish welfare and product quality. Salmon producers in the UK have either already built or are in the process of building such large production units. These systems have clear advantages over land-based or open water loch systems, including a reduction in water usage, improved management of waste, a better control of disease and the ability to manipulate environmental conditions for year round salmon production. However, questions about robustness of these fish when exposed to challenging natural conditions in open seawater cages have been emerging over recent years, especially for gill pathologies and a new anaemic syndrome. While the Industry and Government have strong aspirations for growth of the salmon sector to meet increasing market demands, considerable pressures are being experienced by the farming companies and production, at best, has stagnated over recent years and even decreased since 2015. This is mainly due to fish health challenges at sea resulting in emergency harvests and unsustainable losses at sea. From results obtained by the consortium research teams over the past 4 years, it appears very clearly that conditions experienced by fish early during freshwater development can impact on long-term performance and robustness at sea. The current project aims to characterise the impacts of freshwater environmental conditions including water chemistry, temperature, photoperiod and nutrition, between RAS and open water loch systems, on fish performance and overall health. The main hypothesis tested by the project is that early life history of salmon produced in freshwater RAS impacts on immune barriers (mainly gill, gut and skin), which may predispose fish to gill pathologies at sea. The project will investigate how RAS microbiota (e.g. microbe populations living in the fish intestine, gill and skin) and water chemistry (especially carbon dioxide) impact on fish immune function and performance. The effects of altered environmental regimes (photoperiod, temperature and diet) and vaccines that provide active protection against particular diseases at sea, will be tested on smolt immune function, performance and health following transfer to sea. Finally, the relationship between fish development in freshwater RAS and its impact upon commercial performance and overall health will be studied including the effects of the fish genetic makeup, the characterisation of the new anaemic syndrome and a large-scale epidemiological study. To ensure the success of the project, the consortium brings together world leading scientists from four of the main UK research Institutions working on aquaculture and sustainable livestock development in conjunction with the four leading salmon farming, feed manufacturing and pharmaceutical companies. The project has also a strong support from governmental research centres and industry led organisations. The research will enable the development of practical methods for the production of high quality salmon with benefits for animal welfare and the sustainability and profitability of the industry. Since farmed salmon are a major food source in the UK diet, with more than 1.2 million salmon meals eaten per day, this project also has great significance to the health and well-being of the population in the UK. By supporting the sustainable development of the salmon farming industry, this project will contribute to protect more than 9,000 directly employed and industry-associated jobs in largely rural areas of Scotland and will help create new jobs.