Moving Out Of The Black Box and Back To The Future: Metagenomic Analysis Of The Rumen Microbiota

One might consider the rumen and its microbes as the "x factor" in G x E x M interactions: a dynamic and functional interface affecting animal phenotype via its interplay with genotype, environment and management decisions. Rumen microbiology has recently evolved into a more holistic “metagenomic” discipline, with DNA sequencing and related approaches providing insights of the genetic potential inherent to both the “culturable” and “non-culturable” microbes that impact the availability and yield of energy- and protein-yielding nutrients from feedstuffs. Additionally, the technologies now afford an unprecedented opportunity to provide a depth and breadth of coverage for cohorts of animals that might better cover the biological variation inherent to herds and populations, rather than a few animals. However, the challenge remains to translate this in-depth, but largely descriptive information into pragmatic tools and approaches that will improve animal productivity via improved animal selection strategies, feed conversion, and nutrient retention.

In Australia, perhaps the most pressing challenge presented to our livestock industries by society right now is to reduce methane emissions. This presentation will provide an overview of our progress to date, principally working with Bos taurus and Bos indicus breeds of beef cattle, with using advanced (meta)genome sequencing techniques to characterise what microbial populations and functions constitute a “low” methane rumen in these animals and management systems. The overarching objective is to use this approach to assist with the development of practical ways that will result in a “low methane phenotype” in animals; either by animal selection for the desired rumen microbiota populations and (or) augmenting the metabolic capacity of the greater microbial community (as a complement perhaps to methanogen inhibition).