The Influence of Different Amounts and Sources of Energy upon In Vitro Urea Utilization by Rumen Microorganisms

Abstract

Six different sources of energy, dextrose, cane molasses, sucrose, starch, cellulose, and ground corn cobs, each at three respective levels, were studied in in vitro fermentation flasks with respect to their influence upon rumen microorganisms in converting urea nitrogen into bacterial protein. Each source of energy whether a readily available carbohydrate or a complex carbohydrate, such as cellulose, aided urea utilization provided the latter underwent digestion. It was observed that small amounts of a readily available carbohydrate aided cellulose digestion, which in turn increased urea utilization, whereas large amounts of such materials, inhibited cellulose digestion. These results are discussed with respect to the relative merits of different combinations of readily available and less available carbohydrates as sources of energy in bringing about maximum utilization of urea by rumen microorganisms.