PLASMALOGENS OF MICROBIAL COMMUNITIES ASSOCIATED WITH BARLEY STRAW AND CLOVER IN THE RUMEN

Microbial plasmalogen aldehydes (detected as dimethyl acetals, DMA) have been used to compare microbial populations associated with clover and barley straw incubated in nylon mesh bag in the rumen of a cow. The results suggest that the populations involved in the digestion of these substrates differ substantially and that population changes occur as digestion proceeds: these conclusions were supported by electron-microscopic observations. Analysis of DMA suggested that populations associated with the particles of straw and clover differed more markedly than the corresponding populations in the liquid phase. When straw was pre-incubated with the rumen cellulolytic bacterium Ruminococcus flavefaciens strain 17, the DMA characteristic of this bacterium were present at increased levels during subsequent incubation of the straw in the rumen, though the R. flavefaciens DMA tended to contribute a smaller proportion of the total DMA as the incubation time in the rumen was increased from 24 to 72h.