"Feces of youth" extends fish lifespan by 37 percent
The mysterious world of gut bacteria is a hot area of research in science right now. The systemic implications of our gut flora are being found to have vast holistic effects from potentially affecting the symptoms of autism to influencing neurodegeneration in the brain. New research on the turquoise killfish could point to another effect of our gut microbiome – moderating aging.
Several studies in recent years have found interesting links between aging and gut microbiota. From mice to men we've seen evidence of age-related differences in the microbiome between the old and young. It seems increasingly clear that as we age the variety of bacteria in our gut diminishes.
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Dario Velenzano from the Max Planck Institute for Biology of Aging in Germany set out to see if fecal transplants could alter the lifespan of animals. The killifish was chosen as it has one of the shortest lifespans of any vertebrae on the planet, and it has a remarkably sophisticated gut microbiome. This allowed Valenzano to easily identify any age-enhancing effects of the treatment.
The team treated some middle-aged (9.5-week-old) fish to antibiotics that cleared out their natural gut flora, and then placed them into an aquarium that contained the poo from young fish (5-week-old). While the species are not generally known to eat feces, they were noted as sampling the contents enough to ingest a relevant amount of the younger gut microbes, which subsequently recolonized their own microbiome.
The older fish were then monitored and it was found that at 16 weeks of age (elderly for a killfish) their gut microbiome still resembled that of a young 6-week-old fish. The older fish with the younger gut flora also displayed more youthful behavior, their activity levels likened to that of their 6-week-old counterparts.
But most notable were the general lifespan effects of the fecal "transplant." The fish that received the treatment lived 37 percent longer than those receiving no treatment. The team also experimented with exposing older fish to the gut microbes from middle-aged counterparts, with the younger gut flora influenced fish living 41 percent longer than those with middle-aged gut flora.
The researchers are clear in pointing out that they still don't know how the gut microbiome affects lifespan, but it does point towards a fascinating, and yet undiscovered, mechanism. It's also worth noting that no further research has been done in any mammals or humans, so tracking down some youthful poo and performing your own fecal transplant is not at all recommended ... yet.
The research has been published on bioRxiv.org as a preprint, and is yet to be peer-reviewed.