瘤胃细菌、原虫和真菌降解植物细胞壁的相对贡献及其互作  

Degradation and fermentation characteristics of ruminal bacteria, protozoa, and fungi and their interactions

作　　者：高巍[1] 孟庆翔[1] 

机构地区：[1]中国农业大学动物科技学院,北京100094

出　　处：《中国农业大学学报》2003年第5期98-104,共7页Journal of China Agricultural University

基　　金：国家杰出青年基金资助项目 (30 12 5 0 33)

摘　　要：采用体外产气量法 ,以球磨与未球磨玉米秸细胞壁为底物 ,对瘤胃微生物不同区系降解植物细胞壁的相对贡献和发酵特征进行了研究。用化学试剂和抗生素来分离瘤胃细菌、原虫和真菌 ,并设计下列微生物区系 :全瘤胃液 (WRF)、细菌 (B)、原虫 (P)、真菌 (F)、细菌 +原虫 (B +P)、细菌 +真菌 (B +F)、原虫 +真菌 (P +F)和负对照(CON)。结果表明 ,细胞壁经球磨后可以显著提高瘤胃微生物的产气量和降解率 (P <0 .0 1) ,但不改变发酵类型 ;不同微生物区系的产气量和降解率具有极显著的差异 (P <0 .0 1) ,WRF的产气量和降解率最高 ,其次是混合培养(B +P、P +F、B +F) ,而单培养 (B、P、F)的最低 (P <0 .0 1)。结果说明植物细胞壁在瘤胃内的降解是在细菌、原虫和真菌的协同作用下完成的 ,对植物细胞壁的降解程度可能不是某一种或二种微生物所能及第的。B +P的产气量和降解率仅次于WRF ,表明瘤胃细菌和原虫在降解植物细胞壁过程中存在协同效应 ,对细胞壁降解的贡献率较大。另外 ,随着产气量和降解率的提高 ,发酵液的pH值降低、总VFA、氨态氮和甲烷气体的含量升高 ,进一步证明植物细胞壁的发酵程度提高了。Relative contributions of degradation and fermentation characteristics of various ruminal microbial fractions to milled or grounded corn stover cell wall were evaluated by the method of gas production in vitro. Various chemicals and antibiotics were used to differentiate bacteria, protozoa, and fungi in the rumen fluid, and the following ruminal microbial fractions were constructed: the positive system—whole rumen fluid (WRF), bacterial fraction (B), protozoal fraction (P), fungal fraction (F), bacterial plus protozoal fraction (B+P), bacterial plus fungal fraction (B+F), protozoal plus fungal fraction (P+F), and negative control fraction (CON). The gas production and degradation rate were significantly enhanced by the treatment of cell wall with ball mill (P<0.01); but the pattern of fermentation did not changed. There have significant differences of gas production and degradation rates among the various ruminal microbial fractions (P<0.01). WRF fraction exhibited the greatest gas production and degradation rates to the cell wall of corn stover, followed by the co-culture (B+P, P+F, and B+F), whereas monoculture (bacteria, protozoa, and fungi) showed a very low gas production and degradation rates. These results strongly indicated that the digestion of plant cell wall in the rumen was conducted by the interactions among the ruminal bacteria, protozoa, and fungi, and the coactions of the three groups cannot be alternated by either of them or the combines. However, the bacteria and protozoa may make a significant contribution to the degradation of cell wall of corn stover in the rumen. The pH value, the concentrations of total volatile fatty acids, NH3-N of culture supernatants, as well as the percentage of methane consistently increased with the gas production or degradation rates, which indicated that the fermentation extent rather than the fermentative pattern of plant cell wall was elevated by the ruminal microbial.

关 键 词：瘤胃细菌 原虫 真菌降解 植物细胞壁 相对贡献 互作效应 植物细胞壁 瘤胃降解 

分 类 号：S852.6[农业科学—基础兽医学]