The Study Of Broiler Gastrointestinal Microbial Community Diversity Based On T-RFLP Technique

In this dissertation microbial diversity and its dynamic changes in broiler caecum were studied using technique of terminal-restriction fragment length polymorphism ( T-RFLP), and influences of dietary chlortetracycline and cellulose on growth of microbial community in terminal ileum of broiler were further investigated.Experiment 1 T-RFLP method on microbial community diversity analysis in broiler gastrointestinal tract T-RFLP method of studying the diversity of broiler gastrointestinal microbial community was established by optimizing PCR conditions (selection of primer, amount of template, the reaction system, annealing temperature, and others) according to characteristics of microbial 16S rDNA in broiler gastrointestinal tract. Restriction enzyme digestion time was also explored. Peak Scanner software and T-RELP network database were applied in the method.Experiment 2 Study of diversity and dynamic changes of microbial community in broiler ceca T-RFLP technique was used in this trial to study the diversity and dynamic changes of microbial community in broiler cecato explore the mechanism how nutrition related to growth and development of gastrointestinal microbial community. The results showed that the cecal microbial community diversity was different at different ages, but the difference was not significant ( P>0.05). As birds grew, the richness of cecal microbial community species decreased, and the dominant species became moreobvious. In the relative content of representative T-RFsis more than 0.5% of total, the floras of T-RF36, T-RF37, T-RF39, T-RF57, T-RF164, T-RF168, T-RF188 were normal microflora, while the floras of T-RF52, T-RF186, T-RF244 were temporary flora. T-RFLP technique applied in this trial is a good tool to analyze the diversity and dynamic changes of microbial community in broiler gut.Experiment 3 Effects of chlortetracycline on microbial community diversity in broiler terminal ileum This trial was conducted to study the effects of chlortetracycline on microbial community diversity in broiler terminal ileum during the starter period as well as to explore the microbial detection method of chlortetracycline. The results showed that during the starter period of broiler, the effects of chlortetracycline on microbial community diversity in the terminal ileum were exist. Many T-RFs were obtained in this experiment and there were 17 T-RFs which were representative and their relative content is more than 0.5% of total. Of these T-RFs, T-RF28, T-RF216, T-RF596 were inhibited , while T-RF48, T-RF87, T-RF88, T-RF95, T-RF168, T-RF255 were promoted. The influence of chlortetracycline on uncultured microorganisms in the terminal ileum can be detected. More importantly the microorganisms (T-RF596 and T-RF95) that were sensitive to chlortetracycline can be detected as well. It can be concluded that two T-RFs may be the objective fragment used in the microbial detection of chlortetracycline.Experiment 4 Effects of cellulose on microbial community diversity in broiler terminal ileum This experiment studied effects of cellulose on microbial community diversity in broiler terminal ileum to better understand how dietary fiber influence microbial community diversity in broiler gut. The results showed cellulose can effect the microbial community. With level of cellulose increasing, microbial species decreased and the dominant species became more obvious. Many T-RFs were obtained in this experiment and there were 15 representative T-RFs and their relative content is more than 0.5% of total. Of these T-RFs, T-RF29, T-RF31, T-RF43, T-RF180, T-RF220, T-RF481 were promoted by cellulose, while T-RF38 and T-RF596 were inhibited. Effects of cellulose on microbial community diversity in terminal ileum can be detected by T-RELP technique, which provided an important tool and theoretical reference for further study of fiber nutrition and its relation to gut microbials.