Microbial Ecology and Activities in the Rumen: Part I

Abstract

This review describes the progress which has been made during the last 10 to 15 years in the field of rumen microbiology. It is basically an account of new discoveries in the bacteriology, protozoology, biochemistry, and ecology of the rumen microbial population. As such it covers a wide range of subjects including the isolation and properties of methanogenic bacteria, the role of rumen phycomycete fungi, anaerobic energy conservation, and general metabolic aspects of rumen microorganisms. It also attempts, however, to describe and develop new concepts in rumen microbiology. These consist principally of interactions of the microbemicrobe, microbe-food and microbe-host types, and represent the main areas of recent advance in our understanding of the rumen ecosystem. The development of experimental techniques such as chemostat culture and scanning electron microscopy are shown to have been instrumental in progress in these areas. The paper is concluded with an assessment of our present knowledge of the rumen fermentation, based on the degree of success of experiments with gnotobiotic ruminants inoculated with defined flora and in mathematical modeling of the fermentation. The efficacy of chemical manipulation of the fermentation in ruminant is also discussed in this light.

Correlation between microbial enzyme activities in the rumen fluid of sheep under different treatments

“…For this reason, in EABC we can see the highest value for amylolytic activity in a protein diet, which cannot be seen in other fractions. In this manner some proteolytic bacteria such as B. amylophilus and B. ruminicola [29] and S. bovis [64] included in starch hydrolyzing bacterium, and this means that these types of bacteria have both amylolytic and proteolytic activities. These enzymes are released in buffer after sonication.…”

Leucoagaricus gongylophorus Produces Diverse Enzymes for the Degradation of Recalcitrant Plant Polymers in Leaf-Cutter Ant Fungus Gardens

“…The ability of animals to gain access to nutrients in plant biomass, an abundant energy source in terrestrial ecosystems, is facilitated by the formation of symbioses with microbes, since plant cell walls are largely composed of recalcitrant polymers that most animals are unable to deconstruct (5,6). For herbivorous mammals, especially ruminants, the role of microbes in mediating plant biomass degradation has been described (6,7). In contrast, detailed studies of lignocellulolytic microbes associated with insect herbivores, the most species-diverse and dominant plant-feeding animals in most ecosystems, are limited.…”

Postinoculation Protozoan Establishment and Association Patterns of Methanogenic Archaea in the Ovine Rumen

“…Based on phylogenomic analysis, 31 proteins are uniquely present in all methanogens, strongly indicating that all methanogenic archaea form a monophyletic group exclusive of other archaea and that this lineage likely evolved from Archaeoglobus (15). Methanogenesis serves as the terminal electron sink process during organic matter decomposition in the rumen (16,17) and has long been considered a metabolic waste process accounting for 5 to 15% of metabolizable energy loss in ruminants (17). Anthropogenic methane production is of environmental concern, and efforts to reduce it have focused on the reduction of methane eructation from ruminants, with little success.…”