| Summary: | 碩士 === 國立中興大學 === 動物科學系所 === 100 === An understanding of the dynamics of bacterial community structure in the chicken intestine is essential for selection of diets for optimal nutrition, effective treatment of enteric pathogens, and the development of competitive exclusion products. The microbial diversity, count of bacteria and classification of bacteria in microbiology are many ways to quantitative and qualitative. It’s used in research on PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis), that a more convenient way to explore the changes in the composition of flora. In the present study, establishing the optimal condition of PCR-DGGE, and investigate the transition of the bacterial community structure and the predominant bacteria in the intestine of chicks from hatching to 5 wk of age or diet supplement antibiotic and probiotic were investigated using PCR-DGGE and phylogenetic analysis. The results demonstrated that samples of intestinal contents used lactobacillus-specific primers (LabtufGC / LabtufR), by nested PCR amplification and purification, with 10% acrylamide and denaturing gradient of 35-47.5% of the gel, in order to 80V at 60 ℃ for 16 hours after electrophoresis were stained by the silver staining method, obtain a better separation bands and higher resolution of DGGE profile. Newborn chicks after oral lactobacillus broth three days, digestive tract contents collected for PCR-DGGE, the crop and ileal contents in the DGGE patterns can be detected the bands of lactic acid bacteria that not appear in the control group. With age, the bands number of ileal contents DGGE profiles were decreased, and the biodiversity of Lactobacillus species (Shannon''s index) also decreases. However, the opposite in the cecum, the biodiversity of Lactobacillus species were increase with age. Index of similarity results that the development of lactic acid bacteria were different on disparity parts of the gastrointestinal tract. Crop microflora stabilized after 1-day-old, and ileum microflora in no change after 7 days, as cecal microflora changes due to age, to the late sampling (35 days) continued to vary. Probiotics and antibiotics to promote growth performent of the host mechanisms are not identical, that antibiotics to decrease intestinal bacterial species and reducing the biodiversity of intestinal microflora and to reduce energy waste, the probiotic can improve the biodiversity of lactobacillus on crop and ileum, and the digestive tract microflora to become positive equilibrium, and further to improve the growth performent. Application of PCR-DGGE to monitor the changes of Lactobacillus population in gastrointestinal tract of broiler is feasible. The species of Lactobacillus can be determined by PCR-DGGE combine with molecular cloning technique in the further study.
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