| Much attention has been paied to ruminants which relieve contradiction between people and animal for food due to a lot of use of roughage. The root cause of ruminants using high fiber roughage is the rumen microbe degradation of cellulose. This process must be involved in matter and energy exchange with the environment in order to supply necessary foot and energy to microorganisms, which may cause chemical properties of the external environment and microbial interfacial characteristics a certain change. A lot of researchs about composition and structure of roughage, microbial activity and relationships between feed and host have been studied, but studies about rumen microbial interfacial features rare. This study mainly investigated microbial interfacial properties, traditional chemical features and their relationship in the process of in vitro fermentation of forage and fiber. The research results are as follows:Using5×3factorial experiment design, the five varieties (Gu Mu l,Rice straw, Wheat straw, Corn stover and Alfalfa) of NDF and three kinds of particlesize (<0.15mm,0.15-0.30mm,0.30-0.90m m), determine chemical properties of rumen fluid and interfacial features of rumen microorganisms at12,24,36and48h after in vitro fermentation. The results indicate that NH3-N content increased with the increase of particle size (P<0.05), and NH3-N content of alfalfa, rice straw, wheat straw, corn stover, and GuiMu1reduce in turn (P<0.05). Disappearance rate of dry matter (DMD) and cell membrane permeability (CMP) decreases with the increase of particle size (P<0.05), and volatile fatty acid (VFA) have no significant difference with the increase of particle size. DMD and VFA of GuiMu1, corn stalk, rice straw, straw and alfalfa decreased in turn (P<0.05), and CMP of maize straw, rice straw, straw, and alfalfa GuiMu1decreased in turn (P<0.05).The microbial crude protein (MCP) and surface tension (ST) of corn stalk, rice straw, GuiMu1, wheat straw and alfalfa decrease in turn, and the difference of MCP and ST in3kinds of particle size is not significant, respectively. NH3-N, pH and butyric acid is negatively related to the CMP significantly (P<0.05). DMD, MCP were positively correlated with CMP significantly (P<0.05). MCP and propionic acid show significantly positive correlation with ST (P<0.05).Acetic acid and ST are significantly negative correlation (P<0.05).In vitro fermentation substrates are changed into five kinds of corresponding forage, and the experiment scheme is the same. The results indicate DMD, MCP decrease and VFA first increase then decrease with the increase of particle size, respectively. DMD and VFA of GuiMu1, alfalfa, wheat straw, rice straw and corn stalk gradually decreased (P<0.05). MCP of GuiMu1, wheat straw, corn stalk, alfalfa and rice straw, in turn, decreased (P<0.05).CMP increase with the increase of particle size,and CMP of GuiMu1, alfalfa, rice straw, corn stalk and wheat straw in turn reduced (P<0.05). NH3-N of GuiMu1, corn stalk, wheat straw, rice straw and alfalfa, in turn, lower (P<0.05). rumen fluid surface tension (ST) of alfalfa, GuiMu1, straw, rice straw and corn stalk, in turn, reduce (P<0.05). CSH of wheat straw, corn stalk, GuiMu1, rice straw and alfalfa gradually reduced (P<0.05). zeta potential of rice straw, wheat straw, corn stalk, GuiMu1and alfalfa gradually reduced (P<0.05). Particle size has no significant influence on NH3-N, ST, zeta potential and CSH. DMD have a significant positive correlation with zeta potential and ST, respectively (P<0.05). The results of this article have important theoretical significance for a more in-depth understanding of rumen microbial degradation mechanism of fiber material. |
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