Using physiology to optimise water quality and the sustainability of intensive recirculating aquaculture systems (RAS)

目前的FLIP提案建立在与Skretting（全球最大的水产养殖饲料生产商）合作的现有BBSRC工业伙伴奖的基础上。现有的项目是基于一种新的饮食控制方法，这种方法已经被证明可以在实验室条件下将食物转化为生长的效率提高20%。它使用活鱼的实验室研究来评估水产养殖鱼类的能量成本和健康影响，然后设计最佳的饮食组合以尽量减少这些成本。它的目的是为鱼类节省能量，特别是在进食后的酸碱和盐平衡方面，并尽量减少这些自然干扰对呼吸气体交换和排泄过程的影响。目前的FLIP提案将采用与上述目前由bbsrc资助的项目类似的方法。然而，目前的BBSRC-IPA项目解决的是饮食问题，而FLIP提案专门解决了与集约化循环水养殖系统（RAS）特别相关的新发现的水质变化。目前的FLIP提案旨在利用学术界和工业界之间的双向交流来解决以前未被考虑的因素，这些因素可能对鱼类的生物学和生长效率产生重大影响。通过促进学术和工业人员在各自地点之间的交流，本项目旨在解决与集约化再循环水产养殖系统（RAS）有关的水化学的这些不理想的变化。它旨在确定（最好是防止）这些水质问题对鱼类造成的以前未被认识到的能量成本，这些成本可能损害水产养殖的健康、福利、生长和最终的生产效率。它与安格尔西水产养殖有限公司（AAL）合作，安格尔西水产养殖有限公司是欧洲最大的海洋RAS，也是英国唯一的海鲈养殖场，海鲈是一种高价值和重要的商业鱼类。这种形式的陆基水产养殖由于其低用水量和尽量减少废物造成的环境问题方面的可持续性，在世界范围内日益得到推广。然而，水产养殖条件的强度造成了必须解决的水质问题，主要是鱼类消耗氧气和排出二氧化碳。这可以通过循环水的大规模曝气来补偿，这可以有效地恢复氧气，但通常不足以去除所有动物的二氧化碳废物，从而使水酸化。为了解决这个pH问题，RAS运营商以相当高的成本添加了大量的碱（每天1-2吨烧碱）。然而，这种pH补偿措施现在已经实现，造成了进一步的水质问题，特别是水中的高碱度和低钙。已知这些次生变化会损害鱼类的生理和能量学，因此怀疑会对它们的摄食和生长产生负面影响。通过促进知识和技能的双向转移（通过直接借调一名学者和一名行业交流者，在对方的现场），FLIP项目旨在为这些特定的水质问题提供具有成本效益的、基于证据的解决方案。此外，我们的目标是通过学术-工业合作将解决问题的文化嵌入到两个组织的结构中，以便及时避免或减轻与可持续鱼类生产相关的未来问题。

The current FLIP proposal builds upon an existing BBSRC Industrial Partnership Award in collaboration with Skretting (the largest global producer of aquaculture feed). The existing project is based on a novel manipulation of diets that has already been demonstrated to improve the efficiency of converting food into growth by a remarkable 20 % under laboratory conditions. It uses laboratory studies with live fish to assess the energetic costs and health implications of feeding in aquaculture fish, and then to design optimal diet compositions to minimise these costs. It aims to make energetic savings for the fish in particular regarding acid-base and salt balance following a meal, and minimise how these natural disturbances impact upon respiratory gas exchange and excretory processes. The present FLIP proposal will use similar approaches to the above current BBSRC-funded project. However, whereas the current BBSRC-IPA project addresses dietary issues, this FLIP proposal specifically addresses newly discovered water quality changes that are particularly associated with intensive recirculating aquaculture systems (RAS).The present FLIP proposal seeks to use a 2-way interchange between academia and industry to address previously unconsidered factors that can have a major influence on the biology and efficiency of growth in fish. By facilitating an interchange of academic and industrial personnel between their respective sites this project aims to address these non-ideal changes in water chemistry associated with intensive recirculating aquaculture systems (RAS). It aims to establish (and ideally prevent) previously unrecognised energetic costs for fish caused by these water quality issues that can impair health, welfare, growth and ultimately the production efficiency in aquaculture. It is a collaboration with Anglesey Aquaculture Ltd (AAL), the largest marine RAS in Europe and the UK's only farm for seabass, a high value and commercially important fish. This form of land-based aquaculture is increasingly promoted worldwide due to its sustainability in terms of low water use and minimising environmental problems from waste products. However, the intensity of the aquaculture conditions creates water quality problems that must be countered, primarily a consumption of oxygen and excretion of carbon dioxide by the fish. This is compensated by large scale aeration of the recirculating water which effectively restores oxygen, but is often insufficient to removal all the animal's waste carbon dioxide which subsequently acidifies the water. To deal with this pH problem RAS operators added huge amounts of alkali (1-2 tonnes of caustic soda per day) at considerable cost. However, this pH compensation measure is now realised to create further water quality issues, specifically high alkalinity and low calcium within the water. These secondary changes are known to impair the physiology and energetics of fish, and are therefore suspecting of negatively impacting their feeding and growth.By facilitating a 2-way transfer of knowledge and skills (via direct secondments of one academic and one industry interchanger, at each other's site), this FLIP project aims to provide a cost-effective, evidence-based solution(s) to these specific water quality issues. Furthermore, we aim to embed a culture of problem-solving through academic-industrial collaboration into the fabric of both organisations such that future problems associated with sustainable production of fish can be avoided or mitigated in a timely fashion.