Digestion of rumen bacteria in vitro

1. A pepsin + pancreatin method was used to assess the digestibility of pure cultures of rumen bacteria and mixed bacteria prepared from rumen fluid.
2. Individual species of Gram-negative rumen bacteria were highly digestible, whereas Gram-positive species, especially cocci, were more resistant to digestion.
3. A similar difference was observed microscopically with mixed rumen bacteria, but the influence of the relative proportions of Gram-positive and Gram-negative bacteria on the digestibility of bacterial protein in rumen fluid was small.