There are a large number and a wide variety of bacteria in shrimp intestines, which play important roles in nutrient absorption, growth and development and disease defense. Intestinal bacteria are the main members of intestinal microorganisms, which have been found to be closely related to growth stage, individual size and health status of shrimp. Moreover, once the dynamic balance of intestinal flora of shrimp deviates from the normal and healthy range, the shrimp will exhibit metabolic abnormalities and tissue lesions, leading to the invasion of pathogenic microorganisms. With the continuous deepening of research, experts and scholars at home and abroad have begun to explore the unknown functions of shrimp intestinal microflora and made much progress in recent years, mainly involving growth and development, environmental stress, disease occurrence, feed nutrition, and water quality conditions. During the entire development process of shrimp, the structure of intestinal microflora undergoes significant changes. Intestinal microflora can be adjusted based on shrimp feed, feeding patterns, and nutrient requirements for growth and development, so the dynamic balance of symbiosis is more beneficial to both parties, thereby promoting shrimp growth. The abundance of Actinobacteria significantly increases with the extension of culture time of Litopenaeus vannamei, while α-Proteobacteria showes an opposite trend of change. γ-Proteobacteria is the dominant bacteria in healthy shrimp, accounting for 40% of L. vannamei and 90% of Penaeus monodon. During the early development stage of P. monodon, Proteobacteria dominates, but Actinomycetes becomes the dominant bacteria in the intestinal tract of adult shrimp. γ-and α-Proteobacteria and Flavobacteria are the dominant microflora of L. vannamei at different stages of early development. During the larval stage of L. vannamei, Vibrionaceae occupies an absolute advantage in the intestinal flora, but in juvenile and adult stages, Rhodobacteraceae gradually replaces Vibrionaceae as the dominant bacteria. In the early stage, the intestinal microflora of shrimp is variable, but in the later stage of development, it is relatively stable. In order to coexist with the host, the intestinal microflora of healthy shrimp regards pathogenic microorganisms as invasive species. Once the balance of intestinal flora changes significantly, harmful microorganisms will seize the opportunity to invade, leading to disease of host. There is a significant correlation between the intestinal microflora structure of shrimp and the outbreak of diseases. After an outbreak of disease, the normal activity of the intestinal microflora of L. vannamei is abnormal and presents a relatively disordered state. In recent years, experts and scholars have proposed the concept of microbiota-for-age Z scores（MAZ）, which is a time variant index of intestinal microflora based on the age of the host. MAZ is relatively stable in healthy shrimp, but once diseases occur, MAZ will decline sharply. Therefore, analysis of the structure of host intestinal microflora can assess the health level and susceptibility to pathogens. The core microflora of healthy shrimp is generally dominated by the orders Verrucomicrobiales and Alteromonadales, but during the outbreak of disease, the core microflora gradually shifts to a structure with the orders Rhodobacterales, Vibrionales, and Flavobacteria. There is a significant positive correlation between the immune status of shrimp and relative abundance of intestinal core flora. In order to make the dynamic balance of the intestinal flora and its symbiotic state with the host more conducive to adapting to changes in the external environment, the shrimp intestinal flora can be changed according to environmental conditions of water（ammonia nitrogen, water temperature, salinity, pH, etc.）. As an important ecological factor, salinity is crucial for the growth of cultured shrimp. The intestinal microflora of L. vannamei is closely related to the salinity of water. In highly saline water, multiple conditional pathogens in the intestinal tract increases, leading to a sharp decline in the health level of the shrimp. With the continuous changes of salinity, conditional pathogenic bacteria increase and beneficial bacteria decrease, indicating that continuous changes in salinity can lead to serious imbalance in the structure of intestinal flora and may lead to intestinal dysfunction. Research on the response mechanism of salinity stress to P. monodon has shown that the abundance of Vibrio in high salinity group is higher than that in low salinity group, while the abundance of Shewanella in low salinity group is higher than that in high salinity group. Based on the theory of coevolution, it can be inferred that the interaction between shrimp and its intestinal flora is formed through long-term coevolution, and this symbiotic mechanism can ensure the colonization and reproduction of intestinal bacteria. In other words, the evolution of shrimp intestinal microflora follows Darwin’s law of evolutionary dynamics, and shrimp host and their intestinal microflora must adapt to each other to survive. Establishing criteria for the intestinal microflora of healthy shrimp at different stages of development will help to assess the health level and development status of shrimp. The growth and development, phenotypic traits, and stress resistance characteristics of shrimp are closely related to the composition and structure of intestinal microflora. Therefore, establishing a relationship model between economic traits and intestinal microflora using bioinformatics, macrogenomics and molecular biology will be helpful in improving economic traits and productivity through optimizing the microflora structure. China is recognized as a major shrimp production and consumption country in the world, but there are many problems in China’s shrimp industry, such as frequent disease outbreaks, low feed utilization, and water environmental pollution. Intestinal microflora as a symbiotic partner of shrimp has become the focus of research on healthy shrimp farming. In the process of shrimp culture, it is necessary to rationally mix the nutritional components of the diet at different stages of development to fully utilize the beneficial functions of intestinal flora, thereby promoting intestinal health. Therefore, it is necessary to build a shrimp specific intestinal bacterial strain bank and develop shrimp specific probiotic preparations. In general, the beneficial function of intestinal microflora has been widely recognized, but precise microflora regulation technology is still in the initial stage. An in-depth understanding of the functional characteristics of intestinal flora can lay an important theoretical foundation for the healthy culture of shrimp and improve the production capacity and development and utilization of probiotics. This paper briefly describes the relationship between intestinal flora and growth and development, and disease occurrence. And the effects of feed nutrition and environmental stress on the intestinal flora of shrimp are further reviewed. Finally, this paper looks forward to the research and application trend of shrimp intestinal flora. The paper provides scientific basis for exploring the function of intestinal microbiota, improving shrimp intestinal nutritional health and developing new functional intestinal probiotics.

罗氏沼虾(Macrobrachium rosenbergii)是一种大型长臂淡水虾,亦是世界上最大的淡水虾之一,在我国素有淡水虾王之称.罗氏沼虾具有抗病强、生长快、食性广、肉质鲜嫩等特点,因此深受世界各地消费者的青睐[1].中国罗氏沼虾的产量居于世界首位,并且占据了世界产量的一半以上,这为我国广大的消费群体提供了优质的蛋白源.虽然我国罗氏沼虾养殖产业发展顺利、技术成熟、前景乐观,但存在的问题比较突出,养殖户盲目跟风、技术不规范、产量偏低等问题饱受诟病[2].因此,为了养好罗氏沼虾,为消费者提供优质、健康的水产品,现从苗种培育、增氧、饲料投喂、水质管理、成虾养殖、防病和养殖模式转换等7个方面进行分析,旨在规范罗氏沼虾养殖行为,弥补养殖户的技术短板,加快养殖技术推广与应用,努力营造"创新技术、科技兴农"的养殖氛围.

为研究稻虾综合种养模式中小龙虾的品质,选取了3种不同质量规格的小龙虾进行营养成分分析,结果发现,成体生长阶段的小龙虾营养价值最高.对成体生长阶段的小龙虾进行了活体和死体小龙虾的质构特性和风味物质分析,结果发现:成体小龙虾活体和死体的质构除硬度具有显著性差异外,其他各项参数无显著性差异;小龙虾采样后死亡2h内,肉香味减少,同时产生了多种不良风味物质,建议不要食用死体小龙虾.综上所述,在水产加工阶段,应选择体质量为10～20 g的成体活小龙虾进行加工,以达到最佳的风味、口感和营养价值.

水稻-澳洲淡水龙虾共生综合种养模式主要利用澳洲淡水龙虾与水稻两者互利共生特性以及生长发育时间差异性,合理配置资源.在稻田四周开挖环沟,做好消毒及水草栽培,5月中上旬开始放养澳洲淡水龙虾,提高土壤肥力,减少水稻病虫害,减少农药化肥的使用量.6月中下旬种植水稻,水稻为澳洲淡水龙虾提供了良好的生长环境,实现稻虾共生.该技术模式既能稳定水稻产量,新增水产品,提升稻田亩效益,又能减少农药化肥的使用量,实现经济效益和生态效益双赢.

为促进我国水产养殖产业向绿色、健康和可持续化方向转型,各级政府支持和鼓励水产养殖模式的创新,并且积极推动渔业绿色发展和数字化技术革新[1].作为世界水产养殖大国,渔业养殖设施需要注重系统在节水、节地、节能、减排等方面的功效,从而走上可持续化发展的道路[2-3].循环水养殖模式是未来中国水产养殖发展的主要方向,在适应养殖生产实际的过程中,必须在系统装备的节能优化、设施的简化和运营成本方面作出调整,以降低养殖成本和投资规模,从而引导循环水养殖模式的快速发展[4-5].

长兴位于浙江北部、太湖西南岸,是浙江省淡水渔业重点县,有“丝绸之府、鱼米之乡”之称.长兴自然条件优越,境内山塘、水库、河流众多,池塘、漾荡星罗棋布,水资源丰富,非常适合河蟹的养殖,目前河蟹产业已成为长兴农业特色产业之一.笔者作为湖州市第七至第八批科技特派员,在认真调研的基础上对长兴河蟹产业现状进行了梳理和总结,指出目前所存在的一些问题,并在此基础上提出一些针对性的建议,期望对长兴河蟹产业的健康可持续发展有所裨益.

为了比较池塘和稻虾共生养殖模式下红螯螯虾肌肉的主要营养成分及质构特性,分别采集3批样品进行相关指标检测.结果 表明:2种养殖模式下红螯螯虾肌肉的粗蛋白、脂肪、水分、部分氨基酸和脂肪酸含量存在显著差异,池塘养殖模式下红螯螯虾肌肉中的含量均高于稻虾共生养殖模式;2种养殖模式下红螯螯虾肌肉质构无显著差异;品质评价显示,相对于池塘养殖模式,稻田养殖模式的化学评分(chemical score,CS)、氨基酸评分(amino acid score,AAS)、必需氨基酸指数(essential amino acid index,EAAI)值均与标准蛋白组成更接近,2种养殖模式的致动脉粥样化指数(atherogenic index,AI)、血栓形成指数(thrombogenic index,TI)和多烯指数(polyene index,PI)值均无显著性差异;脂肪酸相关性分析显示,池塘养殖模式下的红螯螯虾肌肉中的棕榈酸、棕榈油酸、十七碳酸、硬脂酸、α-亚麻酸、花生四烯酸、二十碳五烯酸、二十四碳酸和二十二碳六烯酸之间呈显著正相关,稻田养殖模式下的红螯螯虾肌肉中的十五碳酸、硬脂酸与肉豆蔻酸、二十碳一烯酸、二十二碳酸、二十二碳六烯酸与反式亚油酸呈显著正相关,花生四烯酸与二十四碳酸呈显著负相关.综合比较,池塘养殖模式下红螯螯虾肌肉的主要营养成分含量更高,而稻虾共生养殖模式下红螯螯虾肌肉品质更好.该研究可为养殖户及相关研究人员进一步明晰不同养殖模式下红螯螯虾的产出提供理论依据.

一、实施地点及指标 小龙虾、水稻、青虾轮作共生技术模式试验基地在安吉县梅溪镇华光村草滩家庭农场.试验面积120亩.上半年利用闲置稻田养殖小龙虾,苗种选择江苏盱眙小龙虾苗,6月中下旬开始种植水稻,选用单季晚稻品种“浙粳88”,同时放养秋季青虾苗. 主要经济指标:预计示范基地亩产小龙虾150千克,亩产青虾30千克,亩产晚稻450千克,综合亩产值8700元,亩利润4500元.比单一品种养殖或常规水稻种植增产增效明显.

稻蟹共生培育蟹苗技术模式主要是利用种养结合、稻蟹共生互利的原则.蟹的粪便等代谢物为水稻生长提供肥料,水稻中的害虫作为河蟹的动物性饵料,减少了肥料及农药的使用.稻蟹共生的生产结构,可将种植业引进养殖区,改变了单一的养殖结构,也改变了河蟹苗种需要从外地购买的现象,实现生态大米和优质蟹苗双丰收,具有显著的经济效益、社会效益和生态效益.