Fermentation Profiles Of Rumen Microorganisms On Different Substrates And Molecular Analysis Of Bacterial Community

The rumen ecosystem was populated by a highly diverse collection of obligate anaerobic microorganisms, including fungi, protozoa, bacteria and archaea. Relatively, rumen fungi had a less number and slower growth rate compared with rumen bacteria. However, these two type of microorganisms existed in the same ecosystem after millions years of evolving. It may attribute to the rumen physiology, also attribute to substrates utilizing character of rumen fungi and its interactions with other rumen microorganisms. Therefore, our research was focus on the dynamics of microorganism populations and fermentation characters of rumen fungi and bacteria at different substrates (different lignin content substrates and different concentrate to forage ratio substrates). This dissertation was described in the following six sections.1 Fermentation characters of substrates with different lignin content by rumen fungi and bacteria in vitroRyegrass leaf, ryegrass stem, rice straw, peanut hull, representing low to high level of lignin content, were used as substrates, the fermentation profiles by rumen anaerobic fungi and bacteria were determined using in vitro fermentation techniques. During in vitro fermentation by rumen anaerobic fungi, ryegrass leaf, ryegrass stem and rice straw showed no apparent differences in gas production, dry matter loss and cellulose loss. However, dry matter loss and cellulose loss declined significantly with the rising of lignin content in different substrates by rumen bacteria (p<0.05). By the end of 96 h fermentation, xylanase activity of rice straw by rumen fungi was higher than that of ryegrass leaf and ryegrass stem significantly, and xylanase activity was 23 to 65 times higher than CMCase at same substrate. Fermentation by rumen bacteria, however, xylanase and CMCase activity of rice straw were lower than those of ryegrass leaf and ryegrass stem significantly (p<0.05).2 Rumen fungi attachment on and degradation of substrates with different lignin in rumen of goats and in vitroNylon bag in rumen of goats and in vitro fermentation techniques were used to...