Effects of Choline on Rumen Microbial Metabolism

In vivo and in vitro experiments were initiated to examine the effects of choline on bovine rumen microorganisms. Choline increased bacterial numbers indicating a possible choline or methyl group requirement of some rumen microbial species. Although the in vivo and in vitro results were not in complete agreement, in general total fermentation gas production and volatile fatty acid concentrations increased with choline supplementation but neither gas composition nor molar proportions of VFA's were altered. Microbial response patterns suggest that the level of choline supplementation is critical, with the level depending on such factors as choline content of the feedstuff, effect of ration ingredients on choline synthesis within the rumen, and ration content and synthesis of other methyl donors.