Hobson P N, Mann S O, Stewart C S
J Gen Microbiol. 1981 Sep;126(1):219-20. doi: 10.1099/00221287-126-1-219.
Four gnotobiotic lambs were fed, after weaning, on a pelleted concentrate diet containing 90% barley. They were inoculated with a defined flora of 11 species of bacteria designed to reproduce the feed digestion of the conventional lamb. Cultural assessments of the growth of the bacteria and analysis of rumen fermentation products showed that rumen function was near normal, and the lambs grew steadily. However, at an age of about 115 to 130 d, rumen function seemed to fail in three of the lambs and they rapidly lost weight and died. The fourth lamb was removed from isolation at about the same time, when there was some slight indication of loss of rumen function. Kept among conventional lambs it then continued to gain weight as did the conventional animals, but its rumen flora changed. The main species in the defined flora remained as major components of the rumen population after the lamb had been exposed to other animals, but in addition a mixed population of other bacteria, like that in conventional animals, quickly developed. Other experiments showed that gnotobiotic lambs could be routinely weaned on to a concentrate feed containing 45% barley and 50% grass and that, when the lambs were inoculated with a defined flora similar to that given to the lambs in the first experiment, an adequate rumen fermentation could be established and the animals would grow. On changing to an all-grass feed, however, rumen function declined and the lambs ceased to grow. A change back to the barley/grass diet restored rumen fermentation and lamb growth, but whereas amylolytic bacteria were present in normal numbers, cellulolytic bacteria were absent and there appeared to be little, if any, fibre digestion. However, the rumen function again appeared to fail at about the same age of lamb as in the first experiment.
4只无菌羔羊在断奶后，以含有90%大麦的颗粒精料日粮为食。给它们接种了由11种细菌组成的特定菌群，旨在重现传统羔羊的饲料消化情况。对细菌生长的培养评估和瘤胃发酵产物分析表明，瘤胃功能接近正常，羔羊生长稳定。然而，在约115至130日龄时，其中3只羔羊的瘤胃功能似乎出现衰竭，它们迅速体重减轻并死亡。第四只羔羊在大约同一时间从隔离环境中移出，当时有一些瘤胃功能丧失的轻微迹象。将其与传统羔羊饲养在一起后，它随后继续像传统动物一样增重，但其瘤胃菌群发生了变化。在这只羔羊接触其他动物后，特定菌群中的主要菌种仍然是瘤胃微生物群落的主要组成部分，但此外，像传统动物中那样的其他细菌混合群体迅速发展起来。其他实验表明，无菌羔羊可以常规断奶并采食含有45%大麦和50%青草的精料，并且当给羔羊接种与第一个实验中羔羊相同的特定菌群时，可以建立充分的瘤胃发酵，动物会生长。然而，当改为全草饲料时，瘤胃功能下降，羔羊停止生长。再换回大麦/青草日粮可恢复瘤胃发酵和羔羊生长，但尽管淀粉分解菌数量正常，但纤维素分解菌缺失，并且似乎几乎没有（如果有的话）纤维消化。然而，瘤胃功能在与第一个实验中羔羊大致相同的年龄时似乎再次出现衰竭。
