Influence Of Different Diet Fiber On Swine Gastrointestinal Tract Microbial Diversity And Volatile Fatty Acid

The aim of this project is to compare the influence of four different diet fiber sources on ileum and feces chyme microbial diversity and its metabolites of growing pigs by the combination of microbial diversity evaluation based on T-RFLP technical analysis and volatile fatty acid yield and composition detection. Experiments are divided into two parts.Experiment 1:Optimization of T-RFLP technical parameters.Total DNA extraction, PCR amplification conditions, the selection of restriction enzymes and T-RFLP data analysis were all under consideration in this part to establish and optimize the T-RFLP technique applied for swine ileum and feces chyme microbial diversity detection. The experimental results suggested that the properly modified CTAB method could be used to extract the total DNA of microbes for T-RFLP detection and T-RFLP analysis could evaluate swine ileum and feces chyme microbial diversity with a high repeatability and maneuverability.Experiment 2:Effects of diet fiber sources on gastrointestinal microbial diversity and metabolism. Experiment was conducted according to the principle of 4 X 4 dutlicate Latin square design and focused on the influence of broccoli, wheat bran, soybean and rice bran on ileum and feces chyme microbial diversity and its metabolites of duodenum-terminal ileum double fistula pigs, as well as the dynamic changes of the ileum and faeces samples collected after feeding 1 and 14 days. The results showed that (1) The change of ileum microflora composition and diversity was not significant after feeding four different fiber diet for 14 days (P> 0.05), but diversity index of broccoli diet increased significantly compared with the wheat bran diet on the 14 days (P< 0.05); (2) Feeding soybean hull diet could improve the feces microbial diversity, and there were significant differences in the diversity index and dominance index compared with that of rice bran diet, as well as the later one of broccoli diet (P< 0.05); (3) The concentrations of acetic acid and branched chain VFA concentration in broccoli diet were significant higher (P< 0.05) and lower in propionic acid concentration (P< 0.05); (4) The concentration of propionic acid concentration in rice bran diet was the highest and there was a significant difference with that of rice bran diet after feeding 14 days (P< 0.05); (5) The straight-chain VFA concentration of soybean hulls groups was significantly higher than the other three groups (P< 0.05).