The Dynamic Changes Of Bacterial Community Stracture On Micro-Fermention Bed Piggery Litter

The development of China’s agricultural economy has been promoted by large-scale farming, however more and more attention has been paid because of the pollution problems caused by large-scale animal husbandry. Since our country introduced it, as a new rearing technique, deep-litter-system has been vigorously promoted, which can effectively solve the problem of animal husbandry and environmental pollution. The core technology of deep-litter-system is activity of microbial communities in the litter, so dominant bacteria of deep-litter-system in the litter and the microbial community diversity become research hotspots in recent years.In this study, dominant bacteria and bacterial community diversity were studied by using pure culturing methods and restriction fragment length polymorphism (RFLP).The results are listed below:1. The experiment of microbial isolation and identification(1)30bacteria and17actinomycetes were isolated from six samples of micro-fermention piggery by using pure culturing methods.(2) Nine strains of microorganisms, which had high degradability of organic materials (starch, protein, fattiness, cellulose), were filtered, six of which were bacteria and three actinomycetes.(3) Six bacteria were identified by using methods of phytophysiology&biochemistry and16SrRNA techniques, The results are as follows:Bacillus stearothermophilus, Bacillus stear other mophilus, Bacillus subtilis, Bacillus licheniformis, Bacillus cereus, Serratia marcescens, Pseudomonas; Three efficient actinomycete were Streptomyce, Spirillospora, Dactylosporangium by using physiological and biochemical methods.2. RFLP Analysis of the micro-fermention piggery samples(1) DNA extraction:Total microbial genomic DNA of six samples of micro-fermention piggery extracted by using helicase and protease double degradation method described by WU Liang (2010), the length of garose gel electrophoresis genomic DNA fragment was approximately21kb; the A260/A280ratio was between1.6and1.8, DNA concentration was between300ng/ul and400ng/ul, which indicated that genomic DNA were of high quality. Therefore, microbial genomic DNA extracted by using this method could be used to do research for bacteria community diversity.(2) We have gained113sequences by comparing analysis with GeneBank. the samples from the first, second and third year of micro-fermention piggery in the nursery stage were grouped28,20and15sequence types, respectively; the samples from the first, second and third year of micro-fermention piggery in the rearing stage were grouped30,24and17sequence types, respectively.(3) Microbial community diversity on micro-fermention piggery would reduce year by year.(4) In our study, of the752clones analyzed, the sequence types obtained were affiliated with Firmicutes, Proteobacteria, Bacteroidetes groups, which the clone distribution weree60%,18.2%,10%, respectively. Firmicutes bacteria played an important role in degradating organic matter in micro-fermention piggery, especially, Bacillus bacteria and Clostridium bacteria, which were dominant bacteria in the first and second year of samples; Proteobacteria bacteria occured in the third year of the samples, which mainly involved in the conversion of sulfur and nitrogen; Bacteroides mainly involved in the carbon cycle of the substance.(5) We have found13uncultured sequences, which have no similarity with known bacterial sequences comparing with GeneBank. What roles these bacteria play in micro-fermention piggery will be well worth researching.