Bacterial Community Diversity Analysis In Different Aquaculture Modes

As the technique of shrimp aquaculture increasingly developed, shrimp aquaculturemakes big contribution of mainstay aquaculture and gets more and more attention andby then ecotypic sustainable shrimp aquaculture can be realized. By improvingfeeding water quality and exploring new type of ecological aquaculture mode, morebenefits could be achieved. The ecological condition of water in aquaculture is thekey to the healthy aquaculture, meanwhile physicochemical factors and the diversityof microorganisms play a crucial role of the ecological aquaculture.In this paper, the water of different aquaculture modes was studied and the modesinclude shrimp-crab mixed mode, shrimp-crab-scallop mixed mode, andshrimp-crab-scallop-fish mixed mode. PCR-DGGE technology was applied in orderto study the community and the change of bacteria groups, meanwhile correspondingphysical and chemical factors were measured since June2013to Oct.2013. Therelationship between physicochemical factors and diversity of microorganisms wasdiscussed by analysis of DGGE combined with statistical analysis of physicochemicalfactors. This provides the data for the detailed study of aquaculture water and lays thefoundation of the improvement of aquaculture water. The main results are as follows:A. Optimization of the method of PCR-DGGE technology for aquacultureeffectively improved the result of DGGE. The water samples were filtered to collectthe microorganisms with the size of0.22-0.45μm. Total DNA in the water sampleswere extracted by CTAB method and the reaction condition of Touchdown PCR wasoptimized. The denaturation concentration of DGGE gel was40%-60%, the conditionof electrophoresis was defined to be60V,60℃,16hours and EB staining.B. In the shrimp-crab-scallop mixed No.2sample, DGGE gel shows25detectablebands with different positions and9OTUs among them were found all the time. Themost abundant bacterial composition was found in Aug. and Sep., June and Oct.shows the opposite way. There is obvious seasonal change in DGGE of the shrimp-crab-scallop mixed No.2sample in June to Oct. The monthly samples weregrouped in2similar groups: Aug. to Oct. and the other months with high similaritybased on UPGMA cluster analysis. This indicates the coherent and stable bacterialcomposition in the shrimp-crab-scallop mixed No.2sample.C. In all samples, DGGE gels shows18OTUs with8of them in high abundance.The less abundant bacterial composition was found in July. The monthly sampleswere grouped in2groups with low similarity based on UPGMA cluster analysis. Thisis closely related to environment factors and diversity in different modes.D. Results of Partial Correlation (PC) and Principal Component Analysis (PCA) ofNo.2sample showed that there is a significant correlation among many variables. Thecorrelation of these factors can be summarized in three principal components. Thefirst principal component, NH4, bands in gel and DO played a crucial role in thebacterial composition in No.2sample.E. Results of Partial Correlation (PC) and Principal Component Analysis (PCA) ofall samples showed that there is a significant correlation among many variables. Thecorrelation of these factors can be summarized in two principal components afterfurther analysis. The temperature, salinity, pH, DTN, TC and bands in gel played animportant role in the comprehensive information of the water samples.