Although at first it sounds very unpleasant, the truth is that fecal transplantation is proving to be a promising tool to modify the bacterial ecosystem of the recipient’s intestine. In humans, it has been shown to be effective in fighting certain strains of Clostridium resistant to antibiotics , and more and more researchers are encouraged to use feces as a vehicle to introduce new bacteria into the microbiome of different animals. For example, recent work in mice showed how fecal transplantation improved their health and lengthened their life expectancy.
Beyond health applications, this striking technique could also help conserve endangered species, as suggested by a study just published in the journal Animal Microbiome , in which the microbes present in the intestinal flora of animals have been analyzed and altered. koalas, revealing that, through a fecal transplant, the eucalyptus species that serve as food for this endearing marsupial can be influenced.
The researchers, from the University of Queensland (Australia), began this study after observing a drastic decrease in the koala population in the Cape Otway area, in the south of the continent. “In 2013, the group reached very high densities, and as a consequence there was a great defoliation in their favorite eucalyptus species ( Eucalyptus viminalis )”, explains Michaela Blyton, one of the authors of the work. “ By decreasing the amount of food available, we subsequently observed a mortality of 70% in the koala population. The striking thing was that, despite the fact that the animals were starving, they did not begin to eat the other species of eucalyptus present in the area ( Eucalyptus obliqua ), despite the fact that there are some koalas that feed exclusively on this type of tree ”, comments the researcher.
Microbes that determine diet
This fact led them to consider the possibility that the type of bacteria present in their intestinal flora was limiting which species of eucalyptus they could digest. Would it be possible to expand the koalas’ diet with a fecal inoculation?
To test this hypothesis, the scientists held a sample of koalas from the Cape Otway population in temporary captivity, that is, those that only fed on E. viminalis and had experienced famine. “Then we collected feces from other koalas tagged with radio-tracking collars and whose diet was exclusively E. obliqua, ” explains Blyton. The next step was to concentrate the microorganisms present in the feces, package them in capsules resistant to stomach acids and feed them to the captive koalas.
Over the next 18 days, the team studied the changes in the microbiomes of the transplant recipient koalas and compared their diet with that of another control group of koalas that had not received the inoculation.
The results revealed that, indeed, the poop transplant produced changes in the intestinal flora of the marsupials, which in turn began to feed on the new species of eucalyptus. “This could affect all aspects of their ecology, including nutrition, habitat selection and resource use,” Blyton muses.
“Naturally, the koalas may have trouble adapting to new diets when deforestation affecting the species of tree which usually feed occurs, or when they are transferred to a new location. In the future, capsules could be used to adjust the microbiomes of koalas before moving them to safer environments, and as probiotics during and after antibiotic treatment , “the researcher concludes.
Reference: Blyton et al, 2019. Faecal inoculations alter the gastrointestinal microbiome and allow dietary expansion in a wild specialist herbivore, the koala. Animal Microbiome.
