主养草鱼池塘三种混养模式下鱼类肠道菌群PCR-DGGE比较

消化道微生物在宿主生长、营养和健康等方面起到重要的作用.本实验采用基于PCR扩增的变性梯度凝胶电泳(PCR-DGGE)技术比较研究了主养草鱼(Ctenopharyngodon idellus)池塘三种不同混养模式下的鱼类肠道菌群差异.结果表明,三种混养模式下同种鱼的生长率出现显著性差异(P＜0.05),而肠道细菌16SrDNA V3区特征片段PCR-DGGE指纹分析显示草鱼的肠道菌群相似性较高(＞42.2％)；投喂配合饲料的草鱼与摄食浮游生物的鲢(Hypophthalmichthys molitrix)、鳙(Aristichthys nobilis和匙吻鲟(Polyodon spathula)肠道菌群结构相差最大(＜19％),鲢和鳙肠道菌群相似性较高(＞41.6％),除模式Ⅱ鳙的肠道和匙吻鲟的胃菌群具有较高的相似性(＞50.3％)外,匙吻鲟的消化道菌群和鲢鳙的相似性低.实验共回收测序了14条特定DGGE条带中的DNA片段,并进行系统进化分析,结果显示,这14条条带分别归属于4个细菌类群:变形细菌门(Proteobacteria),拟杆菌门(Bacteroidetes),厚壁菌门(Firmicutes)和梭杆菌门(Fusobacteria).研究结果为鱼类混养模式的优化,饲料研发和鱼病防治提供了基础参考资料.

Comparative on Fish Intestinal Microbiota from Three Polyculture Patterns in Mainly Cultural Grass Carp Pond by PCR-DGGE

The intestinal microbiota plays an important role in the growth, nutrition and well being of the host, and it would be necessary to know the microflora structure in the gastrointestinal tract and the influence factors. The present study used 16S rDNA polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) technology to investigate the intestinal microbiota diversity of farmed fishes from three polyculture patterns with grass carp(Ctenopharyngodon idellus) as a major component. The results showed that there was significant differences among special growth rate of the same species from the different polyculture patterns after four months’ cultivation and data analysis (P﹤0.05).Whereas PCR-DGGE fingerprinting of V3 region of 16SrDNA indicated that there was a higher similarity (>42.2%) of grass carp intestinal bacteria in different polyculture patterns. The intestinal bacteria between grass carp fed with compound feeds and the filter-feeding fish silver carp(Hypophthalmichthys molitrix), bighead carp(Aristichthys nobilis) and paddlefish(Polyodon spathula) feeding had the lowest similarity (<19%), while a higher similarity was shown between silver carp and bighead carp (>41.6%). As filter-feeding fishes, the intestinal bacterial community structure between paddlefish and silver carp, bighead carp had a lower similarity except the higher similarity (>50.3%) of intestinal flora structure between paddlefish and bighead carp in mode Ⅱ. Fourteen DGGE bands reflecting varying phylotypes were used for sequencing. Phylogenetic analysis of fourteen cloned bands showed that bacterial phylotypes were made up of four phyla bacteria, i.e. Proteobacteria, Bacteroidetes, Firmicutes and Fusobacteria. The study provides basic references to polyculture model optimization, diets development and disease prevention.