鱼类尤其是肉食性鱼类对糖类利用能力低的原因及解决办法是动物营养与饲料研究的重要科学和产业问题。肠道微生物在鱼类消化吸收过程中具有重要作用，它们直接或间接利用鱼类所摄取的营养物质，因而其群落结构也可能会受到宿主食物的影响。我们在前期研究发现摄食不同糖含量食物时，卵形鲳鲹肠道微生物的数量和优势种均发生了改变。在此基础上，本项目提出肠道微生物群落结构能够对饲料糖类产生适应性变化的假说。拟以典型肉食性鱼类-卵形鲳鲹为对象，饲喂不同糖源和糖水平的饲料，运用动物营养学和微生物分子生态学方法，对比分析不同生长发育阶段卵形鲳鲹肠道微生物群落优势种和生物多样性格局等群落结构特征演替规律与糖源和糖水平间的相关性，弄清饲料糖源和糖水平对肠道微生物群落结构的影响，明晰糖在肠道微生物群落构建、演替和相对稳态维持中的作用。旨在从另一个角度思考肉食性鱼类对糖利用能力低的问题，并为寻求改善糖利用的办法提供启发和理论依据。

Carbohydrate is the main metabolism energy in fish feed. Fish especially the carnivorous fish have a relatively low ability to utilize carbohydrate compared with the terrestrial animals. However, the reasons were not clear and further studies are needed to reach a substantial understanding. The intestinal microbiota plays an important role in the process of nutrients digestion and absorption. The bacterial flora of the gastrointestinal tract in general, represents a diversified enzymatic potential, and it seems logical to think that the enzymatic mass lodged in the digestive tract might interfere in a considerable way with a major part of the metabolism of the host animal. Till now considerable information is available concerning the intestinal microflora of terrestrial animals and the role of these intestinal microflora in digestion, very little information is available concerning the bacterial population in the gastrointestinal tract of fish. Since the intestinal microbiota populations grow upon the food absorbed by the host animal,it is reasonable that the microbiota community structural characteristics may affected by dietary nutrients.However, the effects of dietary carbohydrate sources and contents on the intestinal microbiota community were unknown. Whether intestinal microbiota community would adaptively response to the dietary carbohydrate was not clear. In a previous experiment, it was observed that the dominant species and total number of microoganisms of the intestinal microbiota in the gut of Trachinotus ovatus were significantly different between the fish fed with trash fish and those fed with artificial feed with a high content of carbohydrate. This indicated that the dietary carbohydrate may exerted an affect on the intestinal microbiota community characteristics. Based on these findings, we hypothesis that the intestinal microbiota of T. ovatus could adaptively response to variation of dietary carbohydrate sources and/or contents. However, in-depth studies were need to testify the hypothesis. This project aimed to investigate the intestinal microbiota community characteristics e.g. the shift in dominant species biodiversity of T. ovatus in various growing stage by using fish nutrition and molecular microbial ecological methods. And establish an relationship between the variations of intestinal microbiota and dietary carbohydrate sources and/or contents. Illuminate the role of dietary carbohydrates in the constructing and maintaining of intestinal microbiota comminity. This study aimed to provide knowledge which is helpful to understanding why the carnivorous fish can not utilize dietary carbohydrate efficiently. This is may be an important basis for targeting manipulation of the microbial composition and enhance the utilization of dietary carbohydrates.