Varel V H, Jung H G, Krumholz L R
U.S. Meat Anim. Res. Center, U.S. Department of Agriculture, Clay Center, NE 68933.
J Anim Sci. 1991 Dec;69(12):4993-5000. doi: 10.2527/1991.69124993x.
We hypothesized that bacterial species capable of metabolizing phenolic monomers may act as catalysts for forage fiber breakdown by increasing microbial access to cell wall polysaccharides. Ruminal cellulolytic bacteria alone and in combination with phenolic-degrading bacteria were examined for differences in their ability to degrade fiber fractions of alfalfa or bromegrass. Electron micrographs of Fibrobacter succinogenes S85 cultured in combination with the ruminal phenolic-degrading organisms Eubacterium oxidoreducens G41 and Syntrophococcus sucromutans S195 indicated that bromegrass was degraded more extensively by the triculture than by the monoculture. The sequential detergent system was used to quantify the digestibility of fiber components from alfalfa and bromegrass. F. succinogenes incubated with the two phenolic-degrading organisms did not degrade more cell wall material than did F. succinogenes alone. However, with two other ruminal cellulolytic organisms, Clostridium longisporum B6405 and Ruminococcus albus B6403, greater (P less than .05, P less than .10, respectively) amounts of hemicellulose were degraded (72 h in vitro fermentation) from whole-plant alfalfa when E. oxidoreducens and S. sucromutants were combined with the cellulolytic species than when their monocultures were tested. Similar increases were not observed using a NDF preparation of alfalfa as the substrate. Based on these in vitro experiments, it does not seem that E. oxidoreducens and S. sucromutans play an important role in improving forage fiber degradation by cellulolytic ruminal bacteria.
我们推测，能够代谢酚类单体的细菌物种可能通过增加微生物对细胞壁多糖的接触而充当饲料纤维分解的催化剂。单独以及与酚类降解细菌联合培养的瘤胃纤维素分解菌，对其降解苜蓿或雀麦草纤维组分的能力差异进行了检测。与瘤胃酚类降解菌氧化还原真杆菌G41和蔗糖互营球菌S195联合培养的琥珀酸纤维杆菌S85的电子显微镜照片显示，三菌混合培养对雀麦草的降解程度比单菌培养更广泛。采用连续洗涤剂系统对苜蓿和雀麦草纤维成分的消化率进行了定量分析。与两种酚类降解菌一起培养的琥珀酸纤维杆菌，其降解的细胞壁物质并不比单独培养的琥珀酸纤维杆菌多。然而，对于另外两种瘤胃纤维素分解菌，即长孢梭菌B6405和白色瘤胃球菌B6403，当氧化还原真杆菌和蔗糖互营球菌与纤维素分解菌联合培养时，从全株苜蓿中降解的半纤维素量更多（体外发酵72小时），分别达到显著水平（P小于0.05）和接近显著水平（P小于0.10），而单菌培养时则未观察到类似增加。以苜蓿的中性洗涤纤维制剂为底物时，未观察到类似的增加。基于这些体外实验，氧化还原真杆菌和蔗糖互营球菌似乎在提高瘤胃纤维素分解菌对饲料纤维的降解方面并未发挥重要作用。
