The Effect of Carbohydrates and Sulfur on B-Vitamins Synthesis, Cellulose Digestion, and Urea Utilization by Rumen Microorganisms In Vitro

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Abstract
Starch as a source of energy (9.0 gm. starch/flask) as used in this type of artificial rumen stimulated the synthesis of riboflavin, niacin, pantothenic acid, and vitamin B12 and also increased the utilization of urea, but depressed cellulose digestion. A smaller amount of starch (4.5 gm./flask) was not sufficient for the best synthesis of the above vitamins and urea utilization, but supported better cellulose digestion. The inoculum from the steer getting alfalfa hay was more effective in the synthesis of vitamin B12, cellulose digestion, and urea utilization than the inoculum from the poor hay fed steer. The results from the 24 and 30 hour digestion studies were found to be as significant in determining the results of digestion as the 48 and 96 hour. Inorganic sulfur as Na2SO4 and sulfur in methionine stimulated the activity of the rumen microorganisms with the result that more riboflavin and vitamin B12 were synthesized, more cellulose was digested, and more urea utilized than when the source of sulfur was cystine or elemental sulfur. The data obtained indicate that pantothenic acid was synthesized by different microorganisms than those responsible for the other reactions studied in this experiment. This organism apparently has a low sulfur requirement. Ethionine as the source of sulfur depressed the synthesis of all of the products studied. The microorganisms which synthesize riboflavin, niacin, and vitamin B12, digest cellulose, and utilize urea for protein synthesis have a sulfur requirement. Copyright © . .