海水鱼类饲料鱼粉替代新技术的作用机制

Replacement of dietary fish meal is the key to establish sustainable fish aquaculture industry in the world, however, the factors limitting fish meal replacement with alternative ingredients remains to be identified. We have found that the protein structure of soybean and selenium content are the factors responsible to fish meal replacement with soybean meal or soy protein concentrate in diets for marine fishes, and developed a novel technique for formulating low fish meal diets for carnivorous fishes. In this project, we will evaluate the effects of protein structure of soybean and soy protein concentrate and selenium supplementation on intestinal microbes, antioxidant system and immune function of three marine fishes that are commercially important for marine aquaculture in China. The objective of this study will aim at determining the role and mechanisms of intestinal microbes in affecting dietary protein utilization and metabolism, and determing the key factors that modulate the pathway beween the structure of dietary protein, intestinal microbes, immune function, and dietary protein utilization and metabolism. Moreover, this study will test the function of signaling molecules (SM) which were identifed in our previous studies and may exhibited a role in regulating fish metabolism.

降低饲料鱼粉含量是建立可持续海水鱼类养殖产业的关键。有关鱼类饲料鱼粉替代研究已进行40年，但限制鱼类饲料鱼粉替代的原因一直未能明确。申请者前期研究发现大豆蛋白质结构和硒含量是影响利用豆粕和大豆浓缩蛋白替代饲料鱼粉的重要因素，发现了具有调控鱼类代谢的信号分子SM，在此基础上开发出低鱼粉饲料配方新技术。本项目将比较研究大豆蛋白质结构和硒对我国三种重要海水养殖鱼类肠道微生物组成、抗氧化体系和免疫功能的影响，探讨肠道微生物在影响饲料蛋白质利用和代谢方面的作用和机理，明确饲料蛋白质结构→肠道微生物→免疫反应→饲料蛋白质代谢途径中的关键调控因素。同时，确证前期研究中发现的信号分子SM的功能。

降低饲料鱼粉含量是建立可持续海水鱼类养殖产业的关键。前期研究发现大豆蛋白质结构和硒含量可能是影响豆粕和大豆浓缩蛋白替代饲料鱼粉水平的重要因素，发现鱼类代谢产物具有调控鱼类生长和代谢的信号分子作用，提出低鱼粉饲料配方技术。在此基础上，本项目重新评价了网箱养殖大黄鱼饲料蛋白质和脂肪需求以及卵形鲳鲹饲料脂肪需求，评价了利用大豆浓缩蛋白、棉籽浓缩蛋白和羽毛粉替代大黄鱼、花鲈、卵形鲳鲹、条纹锯鮨和日本黄姑鱼饲料鱼粉的潜力以及饲料鱼粉替代对大黄鱼肠道微生物组成和抗氧化酶活性的影响，评价了硒、核苷酸和姜黄素对改善低鱼粉饲料营养价值的作用，比较分析了不同鱼类种类不同养殖环境下（花鲈和日本黄姑鱼）、不同鱼类种类相同养殖环境下（大黄鱼和黑鲷）和同一鱼类种类（条纹锯鮨）不同养殖环境下肠道细菌组成和多样性的差异。项目研究结果确定大黄鱼饲料蛋白需求为490-520 g kg-1，卵形鲳鲹饲料脂肪需求为110 g kg-1；确定通过添加上述替代蛋白源可将大黄鱼、卵形鲳鲹和花鲈饲料鱼粉分别降低到160、140 g kg-1和70 g kg-1；确定饲料可影响鱼类肠道细菌组成并正在开展通过肠道微生物-肠-脑轴途径调控鱼类生长和应激的探索性研究。