Prospects for development and use of recombinant deoxyribonucleic acid techniques with ruminal bacteria.

Over the last decade, developments in recombinant deoxyribonucleic acid techniques and molecular biology have revolutionized bacterial genetics, creating vast, new potential uses of bacteria (as well as animal and plant cells) that were not even considered previously. Bacterial production of hormones is but one example. With bacterial species with well developed genetic systems, such as Escherichia coli, it is now possible genetically to "design" or "engineer" bacterial strains having specific characteristics. One reasonable future approach toward improvement of animal agriculture would be manipulation of the rumen ecosystem via the use of genetically modified ruminal bacteria, but significant obstacles exist with this approach. Genetic systems of ruminal and of anaerobic bacteria of the mammalian gastrointestinal tract, in general, have not been studied and are largely unknown. In this paper, the various criteria for possible establishment of recombinant deoxyribonucleic acid systems in ruminal bacteria are outlined. Secondly, applications for utilizing genetically engineered ruminal bacteria to control digestion of specific feedstuffs, to regulate specific fermentation products, and to control growth of specific bacterial species are discussed.