Identification of slowly metabolized sugars and sugar derivatives that could be used to establish new or modified microbial species in the rumen

For identification of compounds that could potentially be used to sustain a population of new or genetically modified organisms in the rumen, the rates of metabolism of several sugars and sugar derivatives were measured in ovine rumen fluid in vitro. Several sugars and sugar alcohols, including sorbitol, xylitol, dulcitol, arabinose, ribose, and maltitol, were degraded slowly and were therefore identified as candidates for use in this new manipulation strategy. None of the rumen bacteria,Bacteroides amylophilus WP91,Bacteroides ruminicola M384,Butyrivibrio fibrisolvens JW11,Lactobacillus casei LB17,Megasphaera elsdenii J1,Selenomonas ruminantium Z108, orStreptococcus bovis C277, grew on the above sugar alcohols, and onlyB. ruminicola M384 andL. casei LB17 grew significantly on the pentoses. The non-rumen strain,Escherichia coli ML308, grew rapidly on dulcitol and sorbitol; this suggests a possible role forE. coli in manipulation of rumen fermentation.