Interspecies rumen microbiota transplant

A highly diverse microbiota imparts remarkable stability to the rumen ecosystem functions, which I essential to the host ruminant, but that also makes microbes difficult to modulate for improving production. This study tested the resilience of the microbiota by using a massive interspecies transplantation of rumen contents lacking the functionally relevant protozoal community. Four adult rumen-cannulated wethers had their rumens emptied and thoroughly washed before introducing protozoa-free contents from a cow. Rumen fermentation parameters and methane production were monitored throughout the trial. Double-indexed MiSeq sequencing was applied to describe bacterial, archaeal and fungal diversity and qPCR to quantify microbes and estimate changes in the methanogens mcrA functional gene expression. A shift in fermentation profiles and greater inter-animal variation were noticed after microbiota transplant. However, no clear differences in microbial profiles, richness and diversity indices were observed between pre- and post-transplantation, attesting that rumen ecosystem recovered to its former pre-transplantation shape. No relationship between any microbial group and fermentation parameters could be established except the decreased transcription of mcrA and the decrease in methane emissions in the post-inoculation period. These results support the importance of the host-microbiota interplay in the establishment of the holobiont (animal and microbiota) homeostasis. To further explore this communication, RNA-based studies would be more pertinent.