摄食不同饵料的大口黑鲈肠道菌群分析

为了探究投喂冰鲜杂鱼和人工配合饲料对大口黑鲈肠道菌群的影响,本研究采用变性梯度凝胶电泳技术(PCR-DGGE)对摄食不同饵料的2组鲈鱼肠道内容物的细菌群落结构进行了比较分析.结果显示,冰鲜组与饲料组的大口黑鲈肠道菌群组成相似性较低(相似性24％),且冰鲜组肠道菌群多样性高于饲料组.对2组大口黑鲈中共有条带和特异性条带进一步测序分析显示,2组大口黑鲈肠道共有菌有红螺菌、梭菌、保科爱德华菌、嗜麦芽窄食单胞菌和蓝细菌.冰鲜组大口黑鲈肠道中的特异性菌归属为拟杆菌、肉食杆菌、魏斯氏菌和邻单胞菌;饲料组大口黑鲈肠道中的特异性菌归属为黄杆菌、鲸杆菌、柠檬明串珠菌、缺陷短波单胞菌.研究表明,与投喂冰鲜杂鱼的大口黑鲈相比,人工配合饲料降低了大口黑鲈肠道菌群多样性,也抑制了拟杆菌等有益菌在大口黑鲈肠道内的分布.推测饲料组大口黑鲈生长较慢可能与其肠道菌群中拟杆菌与厚壁菌的比值下降有关.研究结果提示,在今后大口黑鲈养殖或者人工配合饲料研制过程中,添加拟杆菌等益生菌也许可促进大口黑鲈的生长和营养吸收.

Effects of different diets on intestinal microflora of largemouth bass(Micropterus salmoides)

Largemouth bass(Micropterus salmoides)has become one of the important famous freshwater fishes in China since the success of their artificial breeding in 1985.However,iced trash fish from offshore is still the main feed during the culture process of largemouth bass,and long-term use of iced trash fish not only puts pressure on the resources and environment,but also brings some of the original ocean pathogenic microorganisms into freshwater aquaculture area.Replacement of iced trash fish by artificial feed is an inevitable trend in the industrial development of largemouth bass,but in fact,the progress of extensive use of artificial feed has been slow.It's reported that demand for fish feed or nutrition is closely related to composition of the intestinal flora of fish,and differences of fish diets also affect the composition of fish intestinal microflora.So,to explore the nutritional needs and feed configuration of largemouth bass,based on intestinal microflora,is a valuable new exploration.In this paper,intestinal microflora of different largemouth bass including feeding iced trash fish and artificial diet were examined to assess intestinal bacteria community structure using the technology of PCR-denatured gradient gel electrophoresis(PCR-DGGE).The results showed that,microflora composition similarity between iced trash fish group and artificial diet group was 24%.Compared with the iced trash fish group,the diversity of intestinal microflora of artificial diet group decreased.The analysis of the common and specific bands from two groups of largemouth bass demonstrated that,the common intestinal bacteria of both groups include Rhodospirillaceae,Clostridium,Cyanobacterium,Edwardsiella hoshinae and Stenotrophomonas maltophilia; the specific intestinal bacteria of iced trash fish group were Bacteroides,Carnobacterium,Weissella and Plesiomonas; the specific intestinal bacteria of artificial diet group were Flavobacterium,Cetobacterium somerae,Leuconostoc citreum,Brevundimonas diminuta.In sum,compared with iced trash fish,artificial diet reduced the diversity of intestinal microflora and also inhibited the quantity of probiotics of largemouth bass.It's speculated that slower growth of largemouth bass feeding artificial diet may be related to the decline in the ratio of Bacteroides to Firmicutes.The results of this study suggested that,in the future,the probiotics such as Bacteroides could be added to artificial diet for improving absorption of artificial diet,and further promoting the growth and nutritional absorption of largemouth bass.