Alterations of In Vitro Rumen Fermentation Patterns With Various Levels of Sucrose and Cellulose

Abstract

Three fermentation trials were conducted using cellulose, ground corn, and sucrose as substrates. These substrates were added to a mixture of equal parts of strained rumen fluid and synthetic saliva solution in tubes with rubber stoppers containing one-way relief valves. The samples were incubated in a circulating water bath at 39 C. A factorial arrangement was used to study the effects of 0, 3, 6, 9, and 12% sucrose levels, 30 and 70% cellulose levels, and incubation periods of 0, 2, 4, and 6, hr on pH, lactate concentration, and volatile fatty acid proportions of the medium. Increasing the level of sucrose produced linear elevations in butyrate and lactate, whereas pH and acetate declined linearly. Valerate increased to the 9% sucrose level, but propionate and isovalerate were not significantly affected. In comparison to the 30% concentration, 70% cellulose resulted in higher pH, lower lactate, and higher acetate. Lactate concentration was highest at two hours of incubation. The maxima were proportionally greater for each higher sucrose increment. During the six-hour incubation period total volatile fatty acid concentration rose and acetate declined linearly, whereas propionate decreased and butyrate increased quadratically. © 1969, American Dairy Science Association. All rights reserved.