Genetic manipulation of rumen bacteria: from potential to reality

Abstract

The development of techniques for manipulating the molecular genetics of bacteria led naturally to suggestions for using this technology to alter rumen function. Despite early difficulties, methods are now available to insert new genetic material into several rumen bacterial species, including Butyrivibrio fibrisolvens, Prevotella ruminicola, and Ruminococcus albus. One strain of B. fibrisolvens has been modified to detoxify a naturally occurring poison that causes major losses of livestock in Australia, Africa, and Central America. The stability of that modified organism has been demonstrated by its recolonization of the rumen and retention of its altered genotype over 5 months in vivo. Many of the persistent doubts about rumen bacterial genetic manipulation and the viability of altered organisms in a competitive environment have been shown to be capable of resolution, and interest in this area of research may be revitalized by these results. Apart from the achievement of specific metabolic improvements, the technology now available will allow extensive characterization of the molecular genetics of rumen bacteria with a precision that was not previously possible.