Evaluating novel plant oilseeds enriched in omega-3 long-chain polyunsaturated fatty acids to support sustainable development of aquaculture

鱼类作为健康饮食的组成部分，其广泛认可的高度有益效果几乎完全来自其高含量的长链欧米茄-3多不饱和脂肪酸，EPA和DHA，已知其对适当的神经发育至关重要，并可防止多种炎症性疾病，包括心血管疾病和一些神经系统疾病。然而，对野生渔业的过度开发意味着人类食物篮子中越来越多的鱼类现在是养殖的。大西洋鲑鱼，一种所谓的“油性鱼”，可以说是必需欧米茄-3脂肪酸的最佳来源，是英国主要的养殖鱼类。巧合的是，养殖的食肉鱼类，包括鲑鱼，传统上是以鱼粉和鱼油为基础的，而鱼粉和鱼油本身来自海洋渔业。水产养殖的持续发展要求饲料从这些有限的、有限的和不断减少的海洋资源转向环境友好和生态可持续的成分，特别是来自陆地农业的植物粉和植物油。然而，植物性饲料的油成分与海洋性饲料的油成分有很大不同，完全缺乏长链ω-3脂肪酸，这不仅对鱼类的健康，而且对人类消费者的健康都有重要影响。因此，水产养殖面临的挑战是如何以可持续和环境友好的方式养殖鱼类，同时保持高水平的长链欧米茄-3脂肪酸，使其具有营养质量和作为人类饮食有益健康成分的地位。该项目的目的是生产新的植物油，通过含有高水平的长链欧米茄-3脂肪酸，EPA和DHA，专门增强以满足水产饲料行业的需求，并可用于替代我们有限的海洋鱼油储备，并防止这种自然资源的过度开发。这项研究的第一个目标是开发出能够在种子中生产和积累EPA和DHA的油籽植物品种。选择的油籽作物，亚麻荠，也被称为假亚麻或黄金的乐趣和油菜籽的亲戚传统上种植的石油在欧洲，将使用合成生物学方法进行修改，这将导致植物代谢工程包括藻类基因制造长链欧米茄-3脂肪酸，EPA和DHA，通常只产生于海洋微藻。第二个具体目标是配制含有新型长链omega-3亚麻荠油的植物饲料，并在大西洋鲑鱼的饲养试验中对其进行测试，这将确定饲料的效率，营养质量和安全性。第三个目标将是研究EPA和DHA在鱼细胞中的代谢，在那里我们可以非常精确地操纵所提供的脂肪酸，并阐明决定细胞脂肪酸组成的生化途径和分子机制，特别是EPA向DHA的转化。这些细胞研究将为代谢工程实验提供信息，为水产饲料配方的最佳性能提供新型油所需的EPA和DHA水平和比例的数据。由于养殖鲑鱼是英国饮食中长链omega-3的主要来源，每天食用超过120万份鲑鱼餐，因此该项目可以为英国人口的健康和福祉做出重大贡献。此外，通过提高英国养鱼业的可持续性，该项目将有助于保护主要在农村地区的6000多个直接就业和与行业相关的工作岗位。

The widely recognised, highly beneficial effects of fish as components of a healthy diet are almost exclusively derived from their high content of long-chain omega-3 polyunsaturated fatty acids, EPA and DHA, which are known to be essential for proper neural development, and protective against several inflammatory conditions including cardiovascular diseases and some neurological disorders. However, over-exploitation of wild fisheries has meant that an ever-increasing proportion of fish in the human food basket is now farmed. Atlantic salmon, a so-called 'oily fish' and arguably the best source of essential omega-3 fatty acids, are the major farmed fish species in the UK. Paradoxically, diets for farmed carnivorous fish, including salmon, have traditionally been based on fishmeal and fish oil, themselves derived from marine fisheries. Continued development of aquaculture requires feeds to move from these finite, limited and dwindling marine resources to environmentally friendly and ecologically sustainable ingredients, specifically plant meals and vegetable oils, derived from terrestrial agriculture. However, the oil components of plant-based feeds differ substantially from those of marine-based feeds, completely lacking the long-chain omega-3 fatty acids, which has important consequences not only for health of fish, but also the health of human consumers. Therefore, the challenge for aquaculture is how to farm fish in a sustainable and environmentally friendly manner and yet maintain the high levels of long-chain omega-3 fatty acids that confer their nutritional quality and status as beneficial and healthy components of the human diet. The aim of this project is to produce novel vegetable oils specifically enhanced to fit the needs of the aquafeed industry by containing high levels of long-chain omega-3 fatty acids, EPA and DHA, and that can be used to replace our finite reserves of marine fish oil and prevent the over-exploitation of this natural resource. The first goal of the research will be to develop varieties of oilseed plants that can manufacture and accumulate EPA and DHA in their seeds. The oilseed crop of choice, Camelina sativa, also known as false flax or gold-of-pleasure and a relative of rapeseed traditionally grown for oil in Europe, will be modified using a synthetic biology approach that will result in plants metabolically engineered by the inclusion of algal genes to manufacture the long-chain omega-3 fatty acids, EPA and DHA, usually produced only in marine microalgae. The second specific goal will be to formulate plant-based feeds containing the novel, long-chain omega-3 Camelina oils and to test them in feeding trials with Atlantic salmon, which will determine the efficiency, nutritional quality, and safety of the feeds. A third goal will be to study the metabolism of EPA and DHA in fish cells where we can manipulate the fatty acids supplied very precisely and elucidate the biochemical pathways and molecular mechanisms involved in determining the fatty acid composition of cells and, in particular, the conversion of EPA to DHA. These cell studies will inform the metabolic engineering experiments by providing data on the levels and ratios of EPA and DHA required in the novel oils for optimal performance in aquafeed formulations. Since farmed salmon are a major source of long-chain omega-3 in the UK diet, with more than 1.2 million salmon meals eaten per day, this project can make a significant contribution to the health and well-being of the human population in the UK. In addition, by improving the sustainability of the UK fish farming industry, this project will help to protect more than 6000 directly employed and industry-associated jobs in largely rural areas.