Novel Omega-3 Sources in Feeds and Impacts on Salmon Health

膳食中的omega-3脂肪酸是有益健康的关键营养素，在免疫系统中发挥关键作用，并有助于心脏的正常功能和大脑的发育。人体不能产生omega-3，这就是为什么吃这些必要的脂肪很重要。鱼和海鲜是人类饮食中omega-3的独特来源，但传统渔业的衰落意味着现在消费的鱼有一半以上是养殖的。直到最近，确保养殖鱼类和海产品中omega-3含量高的唯一方法是通过使用海洋配料、鱼粉和鱼油在饲料中提供这些营养物质。然而，矛盾的是，它们也来自海洋渔业，这些渔业处于可持续的极限，使它们的资源有限。在过去二十年里，水产养殖业的迅速扩张是唯一可能的，因为传统的海洋成分被越来越多的稀释，用更经济的替代品，主要是植物粉和植物油，它们缺乏鱼类中发现的omega-3脂肪酸。因此，近年来，在大西洋鲑鱼(Salmo Salar)养殖场开发这些替代饲料的过程中，养殖鲑鱼中的omega-3水平降低了一半。饮食中的omega-3对鱼类的健康同样重要，就像它们对人类一样。与养殖鱼性能和健康相关的几个负面问题伴随着替代低海洋饲料的开发，有益的omega-3水平降低，包括炎症性疾病的发病率和严重性增加。然而，此外，炎症是对包括寄生虫、细菌和病毒感染在内的所有病原体的免疫反应的关键组成部分，因此目前养殖鱼类饲料中omega-3的低水平对鱼类的健康和福利产生了影响。因此，饮食中omega-3含量降低对鱼类健康的双重影响，以及人类消费者养殖水产品的营养质量，意味着养鱼业，特别是三文鱼养殖业，带头努力突出和缩小关键omega-3营养素的供需差距。具体地说，全球鲑鱼倡议组织宣布了一项招标，要求商业组织每年供应多达20万吨富含omega-3的新型油。此外，包括世界银行在内的一个财团宣布了F3(无鱼饲料)鱼油挑战赛，以创造一种无鱼的“鱼油”替代品。因此，来自海洋微藻和转基因油籽作物的富含omega-3的油的新来源已经开发出来，并作为包括鲑鱼在内的养殖鱼的饲料成分进行了测试。虽然这些研究证明了这些新油在提高养殖鱼类的omega-3含量方面的有效性，但对鱼类健康的影响被忽视了。该项目将直接调查全新的富含omega-3的油作为养殖大西洋三文鱼的饲料成分对健康的重要影响。这些研究的重点不仅是确定新的omega-3来源对鲑鱼对特定疾病和寄生虫挑战的反应的影响，还将确定支撑鱼类健康的生化和分子机制，量化这些新食用油在英国三文鱼养殖业中的使用潜力。该建议是及时的、高度相关的和适当的，因为它通过前沿研究回应了当前的需求，以提高水产养殖中现代替代饲料的质量和有效性，提高产量和饲料效率，同时保持养殖鱼类的健康和改善营养质量，提供更大的可持续性和粮食安全。

Dietary omega-3 fatty acids are key nutrients that have beneficial health effects playing a critical role in the immune system as well as contributing to the normal function of the heart and development of the brain. The human body is unable to produce omega-3, which is why it is important to eat these essential fats. Fish and seafood are unique sources of omega-3 in the human diet, but decline in traditional fisheries means that more than half of all fish consumed is now farmed. Until recently the only way to ensure high levels of omega-3 in farmed fish and seafood was to deliver these nutrients in feeds by using the marine ingredients, fishmeal and fish oil. However, paradoxically, they too are derived from marine fisheries that are at their sustainable limit making them finite and limited resources. The rapid expansion of fish farming in the last two decades has ony been possible with increasing dilution of the traditional marine ingredients with more economical alternatives, primarily plant meals and vegetable oils that lack the omega-3 fatty acids found in fish. Therefore, the development of these alternative feeds in Atlantic salmon (Salmo salar) farming has seen levels of omega-3 in farmed salmon halved in recent years. Dietary omega-3 are equally essential for the health of fish, just as they are for humans. Several negative issues related to farmed fish performance and health have paralleled the development of alternative, low marine feeds with reduced levels of the beneficial omega-3, including higher incidence and severity of inflammatory diseases. However, in addition, inflammation is a key component of the immune response to all pathogens, including parasitic, bacterial and viral infections and so the current low levels of omega-3 in feeds for farmed fish has had consequences for fish health and welfare. Thus, the dual impacts of reduced dietary omega-3 levels on fish health, and the nutritional quality of farmed fish products for human consumers has meant that fish farming, especially of salmon, has spearheaded efforts to both highlight and close the gap between supply and demand for the key omega-3 nutrients. Specifically, the Global Salmon Initiative announced a tender for commercial organisations to supply up to 200,000 tons annually of novel omega-3-rich oils. In addition, a consortium including The World Bank, announced the F3 (Fish Free Feed) Fish Oil Challenge to create a fish-free 'fish oil' substitute. Consequently, new sources of omega-3-rich oils from marine microalgae and genetically-modified oilseed crops have been developed and tested as feed ingredients for farmed fish, including salmon. While these studies have proved the effectiveness of these new oils in increasing omega-3 content of farmed fish, the impact on fish health has been neglected. This project will directly investigate the important health impacts of entirely novel omega-3 rich oils as feed ingredients for farmed Atlantic salmon. The studies will focus on determining not only impact of the new omega-3 sources on the response of salmon to specific disease and parasite challenges, but also on defining the biochemical and molecular mechanisms underpinning fish health, quantifying the potential of these new dietary oils for use in UK salmon farming. The proposal is timely and highly relevant and appropriate as it responds to current needs with cutting edge research to improve the quality and effectiveness of modern alternative feeds in fish farming, enhancing production and feed efficiency, while maintaining the health and improving the nutritional quality of farmed fish, delivering greater sustainability and food security.