Rumen microbiota and dietary fat: a mutual shaping

Area of Science:

• Rumen microbiology
• Animal nutrition
• Biochemistry

Background:

• Dietary fat supplements are used in ruminant farming to alter rumen activity and the fatty acid (FA) profile of meat and milk.
• Unsaturated fatty acids (UFAs), common in fat supplements, negatively affect microbial growth, particularly protozoa and fibrolytic bacteria in the rumen.
• Rumen microbiota detoxify UFAs via biohydrogenation (BH), converting cis-double bonds to trans-fatty acids and saturated fatty acids.

Purpose of the Study:

• To review the effects of dietary fats on rumen microbial communities.
• To understand the process of biohydrogenation (BH) and its impact on rumen function.
• To highlight the role of specific bacterial genera, like Butyrivibrio, in fat metabolism.

Main Methods:

• Literature review of culture-based studies on rumen bacteria and fat metabolism.
• Analysis of recent molecular approaches applied to rumen microbiota.
• Synthesis of data on lipolysis and biohydrogenation (BH) processes.

Main Results:

• Culture studies identified specific bacterial species and strains affected by UFAs or involved in lipolysis and BH, with a focus on the Butyrivibrio genus.
• Molecular techniques have expanded and challenged previous findings on rumen microbiota composition and function in response to fats.
• The biohydrogenation (BH) pathway significantly alters the type and amount of fatty acids available within the rumen.

Conclusions:

• Dietary fats, particularly UFAs, profoundly influence rumen microbial ecosystems.
• Biohydrogenation (BH) is a critical microbial process for detoxifying UFAs, impacting ruminant metabolism.
• Further research using advanced molecular methods is essential to fully elucidate the complex interactions between dietary fats and rumen microbiota.