Rumen microbiota and dietary fat- a mutual affair - News & Features

13 September 2017
Rumen microbiota and dietary fat- a mutual affair

Rumen harbour a wide range of microorganisms including bacteria, protozoa, fungi, archaea, and viruses. This diverse community plays a key role in the breakdown and utilization of feedstuff carbohydrate and protein (from forage, grain) through the process of fermentation.

This activity results in the production of volatile fatty acids (or short-chain fatty acids) and microbial protein, but also results in energy waste due to methane production, making it a major determinant of feed efficiency.

Classical culture

Historically, knowledge about the rumen microbial ecology and the nutrition of microorganisms was obtained using classical culture approaches, which by the 1990s, allowed the characterization of at least 22 major bacteria.

Rapid advances in molecular biology, phylogenetic techniques and the rise of high-throughput sequencing have expanded understanding of the ecology and function of microbial ecosystems in the rumen.

Fighting fats

Although fat content in usual ruminant diets is very low, fat supplements can be given to farm ruminants to modulate rumen activity or the fatty acid (FA) profile of meat and milk. Unsaturated FAs, which are dominant in common fat sources for ruminants, have negative effects on microbial growth, especially protozoa and fibrolytic bacteria.

Fat addition can also result in negative effects (i.e. decreased intake and milk fat content). Moreover, the addition of fat to the diet can modulate rumen function, mitigating methane emissions.

A recent study, published in the Journal Of Applied Microbiology provides an overview of existing knowledge about the interactions between dietary fat and rumen microbiota, from early culture studies to results obtained with currently available molecular methods that point out the limits of previous studies and offer new insights and perspectives into applications.