中文摘要：

鱼粉、鱼油资源的短缺促使全球水产养殖业积极寻找其替代原料,而探究鱼粉、鱼油与其替代物之间的差异尤为重要,其中最主要的差异就是高不饱和脂肪酸（highly unsaturated fatty acids,HUFAs）是否存在及其含量多少。HUFAs是一类碳原子数目≥20、双键数≥3的脂肪酸,具有为动物提供能量、构成细胞膜组分、形成高生物活性物质、调控脂质代谢和免疫功能等重要作用,主要存在于鱼油和某些类别的微藻中。淡水鱼类具备自身合成HUFAs的能力,因此,一般认为HUFAs不是淡水鱼类的必需脂肪酸,无需通过饲料提供。但已有研究指出,饲料中添加一定量的HUFAs能够对淡水鱼类产生积极的营养作用,表明淡水鱼类的脂肪酸营养理论尚需进一步完善。本文综述了HUFAs在淡水鱼类生长、脂质代谢、健康免疫、繁殖特性等方面发挥作用的相关研究结果,明确提出淡水鱼类需要摄取一定水平的外源性HUFAs,指出在当前淡水鱼饲料中普遍使用HUFAs相对缺乏的蛋白源和油脂源的背景之下,HUFAs对淡水鱼类的作用应受到关注。最后,本文对今后淡水鱼类HUFAs营养的研究方向,以及新的HUFAs油脂源的开发前景进行了展望。

英文摘要：

Decreasing global availability of fish meal or fish oil has urged the aquaculture industry to investigate the alternative ingredients. Exploring the dfferences between fish meal or fish oil and their substitution is particularly important. And one of the main differences is whether highly unsaturated fatty acids（ HUFAs） exist and their content. HUFAs are the fatty acids that contain no less than 20 carbon atoms and 3double bonds,which play important roles in supplying energy for fish organism,moderating the membrane compositions,converting to the highly biological eicosanoids,as well as regulating the lipid metabolism and immune response,mainly being contained in fish oil and certain kinds of microalgae. It is acknowledged that freshwater fish has the capacity to synthesize HUFAs de novo,thus HUFAs were not the essential fatty acids and there is no need to be included in the diets. However,considerable researches have proved the nutritional benefits of HUFAs in the freshwater fish,suggesting that the fatty acid theories of freshwater fish remained to be further improved. This paper reviewed the recent results about the effects of HUFAs on the growth performance,lipid metabolism,health status,immunity and reproductive performance of the freshwater fish,indicating that HUFAs should be supplied in diets for the cultured freshwater fish,especially in the context with the use of less-HUFAs-contained protein or oil sources. The role of dietary HUFAs for freshwater fish should be noted in the future studies. Finally,the prospects of future research on HUFAs requirement of the freshwater fish as well as new HUFA-enriched oil source development have been discussed.