Preliminary Study On Variation Of Microbe Quantity And Community Composition In Polyculture Ecosystem Of Crab, Shrimp And Clam

Microbes that is producers, consumers and also decomposers of ecosystem, not only play animportant role in nutrient cycling and energy flow aquaculture ecosystems, but also play a role thatcannot be replaced by animal and plant to maintain a stable breeding environment. Meanwhile, thereis a close relationship between microbes and breeding biology, microbes often are disease-causingpathogens or condition causative pathogen that cause disease of breeding object. In the breedingprocess, surplus bait produced by feeding irrationally, manure produced by feeding object and abuseof biological medicines often lead to water micro-ecological balance that has been severely damaged,and cause directly or indirectly negative impact on aquaculture.Therefore, the health of the farmedenvironment is closely related with the structure and function of microbial communities. Thus, thestudy of microbial community structure and functional characteristics has important theoretical andpractical significance for aquaculture farming in different ecosystems.Trituberculatus distributed in all waters north and south China is China’s major coastaleconomic crabs, but also one of the most important export goods sold. Its rapid growth, profitablefarming, meat, fat fatness, taste delicious, nutritious, has become China’s coastal areas is importantfarmed species.In this study, crabs mixed shellfish ponds for the study, utilization of traditional cultureisolation method, Biolog-Eco method, denaturing gradient gel electrophoresis methods for differentcrab, shrimp and clam polyculture model to study the structure of microbial systems and functionalanalysis of microbial changes in farming systems in different bodies of water, sediment, in order toobtain the optimum proportion of crabs polyculture provide a theoretical basis for the production.The main results are as follows:1Preliminary study on variation of microbe quantity and community composition of shrimp, crabclam culture ponds.From July22,2012beginning to the end of October6, crab, shrimp, clam polyculture pond forwater and sediment change in the number of bacteria and flora species studied.3months of breedingexperimental results show that bacteria number and community composition of different ecosystempresent dynamic change trend during the entire breeding.(1) As time goes on, heterotrophic bacterianumber in water gradually increased in the CBS1mode. In the later stage of experiment, CBS1andCBS2mode was significantly higher than crab monoculture model; sediment bacterial communities of each model in sediment is same as in water during the entire breeding, but CBS2and CBS3modewere significantly higher than monoculture model, and CBS1mode heterotrophic bacteria number isnot increased significantly like CBS3and CBS2.(2) Bacterial communities in water and sedimentremain some differences to different modes during the entire breeding. The number of bacterialcommunities in water is most in the CBS1, followed by in the CBS2; the number of bacterialcommunities in sediment is most in the CBS3, followed by in the CBS2. On the whole, however, thediversity of the bacterial community in water is more abundant in sediment.(3)By each modelcomparison, Shannon index of bacterial community in water is higher than in sediment; bacterialcommunity diversity index in water of CBS1and CBS2were significantly higher than swimmingcrab monoculture; microbial community diversity index in sediment of CBS2and CBS3weresignificantly higher than in monoculture model.In summary, compared with the crab monoculture model, polyculture Chinese shrimp andwhite shrimp can significantly improve the metabolic activity of bacterial communities and waterbacterial diversity; white shrimp and Japanese shrimp polyculture can significantly increase bacterialmetabolic activity and microbial community diversity in sediment. By comparing the three shrimp,white shrimp polyculture may be more helpful to optimize structure and function of bacterialcommunities of polyculture ecosystem.2PCR-DGGE analysis on bacterial community composition of shrimp, crab, clam culture pondsFrom July22,2012beginning to the end of October6, crab, shrimp and clam on communitydiversity polyculture pond water bacteria were studied. Results of three months’breeding experimentshow that:(1) There are some differences among different model and high richness of microbe andmore groups of bacteria for polyculture model, while it is highest richness of microbe and groups ofbacteria for CBS3by following CBS1. In experiment,64DNA fragments of specific DGGE bandswere collected with three times and sequenced, while phylogenetic tree is established to analyze it.Results show that this64DGGE bands belong to six microbial groups: Proteobacteria, Spirochaetes,Firmicutes, Actinobacteria, Glomeromycota and Pyrrophyta.(2) From CA and electrophoreticanalysis diagram of four treatments in different month, it can be looked that in the initial stage ofexperiment, little differences of aquatic microbial communities in water for each mode reflect that itis low level and steady-state microbial community structure in water in early farming period; overtime, the composition of bacterial communities in water for different systems occur graduallydifferentiation, while bacterial community composition is largest different between CBS2and CBS3and crab monoculture; in the late stage of experiment, bacterial community composition is largestdifferent between polyculture mode bacterial community structure and crab monoculture model.Going With breeding, it is changing that different groups of bacteria live better in different breeding patterns. It can be seen from the CA1and CA2axis position of different breeding patterns,monoculture mode changes in the composition of bacterial community structure more intense, butthe point has been polyculture model scale fluctuations in the vicinity of0, indicating that microbialcommunity structure polyculture model comparison stable, because the dramatic flora resulting in asmaller potential disease outbreaks.(3) RDA analysis showed that change of microbial communitystructure in water is significantly correlated with environmental factors. In July, NH4+-N, NO3--N,PO4-P, NO2--N and TN, which are significantly correlated with change of microbial communitystructure in water, are mainly affective factors of microbial community structure. In August, NH3+-N,NH3+-N, PO4-P, NO2--N and TN are mainly affective factors of microbial community structure. InSeptember, NH3+-N, NO2--N, TN and TP are mainly affective factors of microbial communitystructure. The study concluded that bacterial community structure of different breeding patterns havesignificant changes; comparatively speaking, community Structure of CBS2is most complex andbiological diversity is richest; bacterial community structure of different breeding patterns issignificantly correlated with environmental factors.（4）By comparing bacterial community structureof each polyculture farming mode during the entire composition, changes of the composition ofbacterial groups for CBS2is relatively more stable comparing with the other two modes, andcrab,clam and white shrimp may be more helpful to optimize bacterial community composition ofbreeding ecosystem. This has important guiding significance for the study of microbial diversity inwater for different environments and provides a theoretical basis for future artificial crabs shrimppolyculture.3The microbial community diversity and function study of crab, shrimp, clam culture pondsecosystem.From July22,2012beginning to the end of October6, crab, shrimp, clam on communitydiversity polyculture pond water and sediment bacteria were studied.The results show that Differentpatterns of ecosystem bacterial communities metabolism during the entire breeding show changingtrends, the number of carbon substrate utilization and the use of strength also has a big difference.(1)As time goes on, metabolic activity of the bacterial community gradually increased in CBS1mode,and gradually reduced in CBS3mode. In the later stage of the experiment, CBS1and CBS2modewas significantly higher than crab monoculture model; Post-test for each mode of sediment bacterialcommunities metabolic intensity differentiation obviously, CBS2and CBS3mode was significantlyhigher than monoculture model, CBS1was significantly lower than the monoculture model.(2)Different patterns of water and sediment bacterial communities on the use of carbon speciesdifferentiation significant over time. In the later stage of the experiment, CBS1mode water bacterialcommunities and CBS3modes sediment bacterial communities on using six categories of carbon intensity were significantly higher than crab monoculture model in general (P<0.05).(3) Eachpattern comparison, water bacterial community features Shannon index and Simpson index wassignificantly different in the latter experiment (P<0.05), McIntosh index during the entireexperiment, there were significant differences (P<0.05), CBS1and CBS2mode three kinds of waterbacterial community diversity index were significantly higher than swimming crab monoculture(P<0.05); CBS2and CBS3mode sediment bacterial communities function McIntosh index wassignificantly increased with time trend, but over time monoculture model showed a significantdownward trend. CBS2and CBS3model in late experiments sediment microbial communitydiversity index were significantly higher than in monoculture model (P<0.05). In summary,compared with the crab monoculture model, polyculture Chinese shrimp and white shrimp cansignificantly improve the metabolic activity of microbial communities and water bacterial diversity,polyculture white shrimp and Japanese shrimp can significantly increase the sediment bacterialmetabolic activity and the microbial community diversity. Comparison of the three shrimppolyculture white shrimp may also help optimize polyculture ecosystem structure and function ofbacterial communities.