The utilization of non-protein nitrogen in the bovine rumen. 7. A qualitative and quantitative study of the breakdown of carbohydrate which accompanies protein formation in bovine rumen contents during in vitro incubation

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Abstract
Several carbohydrates and other compounds were incubated in fresh rumen liquid at a concn. of 1% Portions of the same rumen liquid-were incubated with 1 % maltose or glucose as control. The polysaccharides starch and inulin, the trisaccharide raffinose and several disaccharides, hexoses and pentoses were found to be readily utilized by the bacteria. Molecular configuration was important since fructose was readily fermented while sorbose showed no activity. Similar ly, L-(+)-arabinose gave marked bacterial growth, whereas with D-(-)-arabinose activity was much more limited. None of the other substances tested[long dash]lower fatty acids, lactic acid, succinic and tartaric acids[long dash]gave rise to bacterial growth as measured by protein synthesis. A quantitative study has been made of the principal products formed when maltose, arabinose and xylose are utilized in vitro by the microflora of the bovine rumen during an incubation period of 4 hrs. In 3 expts. with maltose, 90-96% of the carbon of the maltose fermented was accounted for by the tormented was accounted for by the formation of lower fatty acids, lactic acid, CO2, methane, bacterial protein and polysaccharide. In 2 expts. with xylose and one with arabinose 83-93% of the C of the decomposed sugar was accounted for. The results for the pentoses differed from those obtained with maltose in that with the pentoses no lactic acid was detected among the end products.