Reconsidering rumen microbial consortia to enhance feed efficiency and reduce environmental impact of ruminant livestock production systems

Abstract

Because cultivation-based approaches to assess rumen microbiology assess only the minority of microbial groups and can miss opportunities to assess important functions, molecular-based approaches have flourished in microbial ecology and have been adapted to the rumen. Current approaches are described herein, specifically for a robust adaptation to nutrition studies or future opportunities. These included automated profiling techniques, density gradient gel electrophoresis, and future adaption of microarray or high-throughput sequencing technologies. Based on current knowledge, a more holistic approach is needed to describe various functional groups of microbes within the context of how they influence, and are influenced by, the whole consortium (combination of microbial groups). Such a perspective is applied to issues related to increasing fiber digestibility when feeding concentrate or unsaturated fats to high producing beef and dairy cattle. These same microbial populations should help to provide growth factors for fibrolytic bacteria while competing against the hyperammonia-producing bacteria such that there would be less need for excessive rumen-degraded protein as a safety factor. Moreover, these same dietary conditions influence the processes of biohydrogenation and methanogenesis. After accounting for population structures of bacteria, protozoa, methanogenic archaea, and even fungi, efforts to integrate molecular-based rumen microbial ecology with dietary conditions should allow us to better explain and therefore predict conditions that will improve feed efficiency and reduce environmental impact of ruminant production systems.

Extending Burk Dehority’s Perspectives on the Role of Ciliate Protozoa in the Rumen

“…Dr. Dehority was involved in research explaining how bacteriocins target other bacteria (Chan and Dehority, 1999), which could also be affected by the protozoal community if they have a major role shaping the bacterial community. Bacteriocin research leaves unanswered questions for animal production (Firkins, 2010).…”

Variations among animals when estimating the undegradable fraction of fiber in forage samples

“…The diversity of microorganisms able to colonize the ruminal environment remains unclear, with reports identifying more than 2000 species of bacteria (FIRKINS, 2010). Several of these bacterial species use the same substrate as a source of nutrients and may produce dissimilar products (EDWARDS et al, 2008).…”

0474 Comparison of digestion and particle-associated bacteria after in situ incubation of different barley varieties in the rumen of cattle

“…Rumen bacteria have been classified into three groups according to the rumen environment, including; (1) free-living bacteria associated with the rumen liquid phase, 2bacteria associated with feed particles, and (3) bacteria attached with rumen epithelium. The liquid fraction and solid fraction samples have been frequently analyzed because these two fractions are largely involved in the digestibility of feed particles in the rumen (Firkins, 2010). whereas Firmicutes was the most prevalent phyla in the solid fraction (Gruninger et al, 2014).…”