Have you had success with the fecal transplant

Surprising hope for threatened koalas: fecal transplants

It is far from clear what goes on in our intestines - but researchers are increasingly interested in it, because the trillions of bacteria that live there are by no means only relevant for digestion. Scientists are finding more and more evidence of how the specific composition of our intestinal flora affects a wide variety of processes in our body. It appears to affect both our physical and mental health.

In view of these findings, there is also increasing medical interest in what at first glance appears to be a rather unpleasant form of treatment - fecal transplantation. What is actually meant is the transfer from the stool of a healthy donor into the intestine of a patient in order to favorably influence the microbial composition there. This does not only work in humans: Numerous experiments show that the complex community in the intestine also affects other mammals and can be artificially changed.

Inflexible eucalyptus enthusiasts

So far, of course, it has mostly been about researching diseases and finding new treatment options. An Australian research team is now attracting attention with another suggestion: They advise using fecal transplants to make threatened koalas more adaptable leaf-eaters and thus increase their chances of survival.

At the beginning of the study, which Michaela Blyton from the University of Queensland and colleagues published in the journal "Animal Microbiome", there was the observation of a koala disaster in a national park in the Australian state of Victoria: In 2013 the koala population there had increased significantly, As a result, the preferred food source of the marsupials became increasingly scarce - the rod-shaped eucalyptus (Eucalyptus viminalis). The animals are known as food specialists; the absolute majority of them feed on eucalyptus leaves. But there are different types of it.

To the surprise of the biologists, however, the koalas did not switch to other eucalyptus species to which they would have had access, even in the greatest need. The result was dramatic: "There was a death rate of 70 percent," says Blyton. "Although the animals were starving, they did not eat the leaves of other eucalyptus trees, even though other koala populations feed exclusively on these."

Excrement experiment

That gave Blyton and her colleagues an idea: What if the composition of the intestinal flora is decisive for which eucalyptus species the respective koalas can digest and which cannot? And could the endangered animals possibly become a little more eucalyptus generalists by changing their intestinal flora?

For their study, the biologists temporarily caught wild koalas that only feed on rod-shaped eucalyptus. In the next step, they collected feces from another koala population, which in turn prefers the species Eucalyptus obliqua. In the laboratory, the researchers then analyzed the intestinal bacteria of both populations and indeed found clear differences.

Changed intestinal flora

So the researchers concentrated the microorganisms from the feces samples of one population and made capsules from them, which they in turn administered to the koalas of the other group. Continuous studies have shown effects: the intestinal flora of the koalas that received the fecal capsules changed - and with it their appetite for the unfamiliar species of eucalyptus. Even if the animals continued to prefer the leaves of their traditional tree in the 18-day trial, they now seemed to tolerate the other eucalyptus better.

In the future, fecal transplants could be used to adapt the microbiomes of koalas to the respective conditions of their environment, the researchers write. This would be an unusual but big step for the protection of the marsupial mammals that are threatened in parts of Australia, whose habitats are increasingly fragmented. (David Rennert, August 24, 2019)