Molecular biomarkers of muscle growth and quality traits in Atlantic salmon: gene-nutrient interactions in fast and slow growing strains

为什么研究大西洋鲑鱼的肌肉生长和品质特征很重要？在过去的20年里，养鱼已经发展成为苏格兰农村地区的主要产业，2003年的商店价值约为8亿GB。世界水产养殖业发展的一个主要因素是开发能够提高生长速度和食物转化效率的饲料和饲料方案，同时降低生产成本和改善环境可持续性。随着全球对鱼粉和鱼油的需求不断增加，转向植物蛋白等替代原料来源的需求也越来越大。因此，有必要测试来自可持续来源的新原材料，通常是植物来源，并确定原材料中可能为鱼类或消费者提供特定健康益处的任何生物活性成分。过去是如何提高增长和质量的？任何新的饮食配方都必须能够维持高生长速度和良好的肉质。传统上，新三文鱼饲料的开发包括配制少量压榨饲料，并在受控环境条件下进行水箱饲养试验。然后，将最有希望的配方进行昂贵的大规模商业或半商业营养试验，以全面评估日粮对生长速度、饲料转化效率和品质参数(肉色、质地和脂肪含量)的影响。为什么这个项目是新的和创新的？最近的鱼类遗传学革命，对四个基因组进行了测序，以及哺乳动物如何调节肌肉质量的知识显著增加，尚未被用于理解鱼类复杂的生长和质量特征的机制。众所周知，食品中的原料含有会影响生长和品质特征的化合物。分子生物标记物提供了生物体生理状态变化的早期迹象。该项目的一个成果将是确定一套生物标记物，以预测喂鱼特定饲料的生物后果，而不必进行非常昂贵和耗时的水箱和海笼试验。在这个项目期间会发生什么？通过对哺乳动物的研究，我们可以推断出可能成为肌肉生长状态和肌肉质量良好生物标志物的候选基因/蛋白质。由于有关生长调控的知识还处于早期阶段，特别是在鱼类中，我们还将使用基因组方法，试图发现在从低生长到高生长速度饲料过渡后，在慢速和快速生长鱼类(新候选)的肌肉中差异表达的新基因。这些候选生物标志物的表达时间进程将与肌肉和质量特征(脂肪、颜色)的细胞和结构变化一起进行研究。统计技术将决定有多少生物标记物可以预测增长和质量，以及我们对预测的有效性有多大信心。这项分析还将检验关于鲑鱼肌肉生长调节的具体假设，并进一步了解遗传构成和环境如何相互作用，影响肌肉生长和肉质特征。该项目开发的鱼类营养研究的新工具将缩短将新产品推向市场所需的时间，并通过提供一种测试来自可持续来源的饲料的新原材料的手段，促进环境友好型水产养殖。

Why is studying muscle growth and quality traits in Atlantic salmon important? Over the last 20 years fish farming has developed into a major industry in rural parts of Scotland, with a shop value of ~ £800 million in 2003. A major factor in the development of the aquaculture industry world-wide has been development of diets and feeding regimens that can improve growth rate and food conversion efficiency, whilst reducing production costs and improving environmental sustainability. With increasing global demand for fish meal and oil there is an increasing demand to move towards alternative raw material sources such as plant proteins. It is therefore necessary to test new raw materials from sustainable sources, often of plant origin, as well as identifying any bioactive components in raw materials that might provide specific health benefits for the fish or consumers. How has growth and quality been improved in the past? Any new diet formulation must be capable of sustaining high growth rates and good flesh quality. Traditionally, the development of new salmon diets has involved formulating small quantities of pressed feeds and testing them in tank-based feeding trials under controlled environmental conditions. The most promising formulations are then taken on to expensive large-scale commercial or semi-commercial nutritional trials in order to fully assess the effects of the diet on growth rate, feed conversion efficiency and quality parameters (flesh colour, texture and fat content). Why is this project new and innovative? The recent revolution in fish genetics, with four genomes sequenced, and the significantly increased knowledge of how muscle mass is regulated mammals has yet to be applied to understanding the mechanisms of complex growth and quality traits in fish. It is known that the raw materials in food contain compounds that can affect growth and quality traits. Molecular biomarkers provide an early sign of a change in an organism's physiological status. One outcome of the project will be the identification of a suite of biomarkers to predict the biological consequence of feeding fish a particular diet without having to conduct very expensive and time-consuming tank and sea cage trials. What will happen during this project? From work on mammals we can deduce the candidate genes/proteins that are likely to make good biomarkers of muscle growth status and flesh quality. Because knowledge about growth regulation is at an early stage, particularly in fish, we will also use genomic approaches in an attempt to discover new genes that are differentially expressed in the muscle of slow and fast growing fish (novel candidates) following transition from low growth to high growth rate diets. The time course of expression of these candidate biomarkers will be investigated together with cellular and structural changes in the muscle and quality characteristics (fat, colour). Statistical techniques will determine how many and which biomarkers can predict growth and quality as well as how confident we can be about the validity of the predictions. This analysis will also allow specific hypothesis about the regulation of muscle growth in salmon to be tested and further understanding of how genetic make-up and environment interact to affect muscle growth and flesh quality characteristics. The new tools in fish nutrition research developed in the project will shorten the time it takes to bring new products to market and contribute to environmental friendly aquaculture by providing a means of testing new raw materials for feeds from sustainable sources.