Metatranscriptomics uncovers diet-driven structural, ecological, and functional adaptations in the rumen microbiome...

Area of Science:

• Rumen microbiome ecology
• Ruminant feed efficiency
• Metagenomics and host-microbe interactions

Background:

• The rumen microbiome is crucial for feed efficiency in ruminants.
• Mechanisms linking microbial adaptations, diet, and host feed efficiency are poorly understood.
• Understanding these interactions is key to improving ruminant production sustainability.

Purpose of the Study:

• To investigate the ecological mechanisms governing rumen microbial communities in relation to host feed efficiency.
• To identify microbial lineages and functional adaptations associated with high versus low feed efficiency.
• To explore the role of host-microbe interactions in modulating feed conversion in cattle.

Main Methods:

• Analyzed 120 metatranscriptomic datasets from Angus bulls with high or low feed efficiency.
• Utilized Neutral Community Model analysis and carbohydrate-active enzyme profiling.
• Compared microbial community structures and functional capacities across different diets (forage vs. grain).

Main Results:

• Stochastic processes largely govern rumen microbial community structures in both high and low feed-efficiency groups.
• High-feed-efficiency bulls showed positive selection for specific diet-responsive microbial lineages (e.g., Fibrobacter, Butyrivibrio, UBA1067).
• These selected microbes possess carbohydrate-binding modules enhancing substrate degradation, unlike low-efficiency bulls with random structures and reduced specialization.

Conclusions:

• Cattle with higher feed efficiency promote microbial populations functionally aligned with dietary inputs (efficient host-mediated microbial amplification).
• Microbiome ecological assembly and functional adaptation are critical contributors to host feed efficiency.
• Findings provide a foundation for microbiome-informed strategies to enhance ruminant production sustainability.