Spending time in close contact with others often means risking catching germs and getting sick. But being sociable may also help transmit 鈥済ood鈥 microbes, finds a multi-institutional study of gut microbiomes in chimpanzees.
Researchers monitored changes in the gut microbes and social behavior of wild chimpanzees over eight years in Gombe National Park, Tanzania. They found that the number of bacteria species in a chimp鈥檚 GI tract goes up when the chimps are more gregarious.
The results help scientists better understand the factors that maintain a healthy gut microbiome.
The warm, soft folds of our intestines are home to hundreds of species of bacteria and other microbes that help break down food, synthesize vitamins, train the immune system and fight infections. Reduced gut microbial diversity in humans has been linked to obesity, diabetes, Crohn鈥檚 and other diseases.
鈥淭he more diverse people鈥檚 microbiomes are, the more resistant they seem to be to opportunistic infections,鈥 said Andrew Moeller, research fellow at the University of California, Berkeley, who co-authored the study published in the Jan. 15 issue of Science Advances.
Moeller and colleagues analyzed the bacterial DNA in droppings collected from 40 chimpanzees between 2000 and 2008. The chimpanzees ranged in age from infants to seniors.
The researchers identified thousands of species of bacteria thriving in the animals鈥 guts, many of which are also commonly found in humans, such as species of Olsenella and Prevotella.
The team then combined the microbial data with daily records of what the animals ate and how much time they spent with other chimps versus alone.
鈥淐himpanzees tend to spend more time together during the wet season when food is more abundant,鈥 said 老牛影视 research scientist Steffen Foerster, who co-authored the study. 鈥淒uring the dry season they spend more time alone.鈥
The researchers found that each chimpanzee carried roughly 20 to 25 percent more bacterial species during the abundant and social wet season than during the dry season.
But the microbiome differences weren鈥檛 solely due to seasonal changes in the fruit, leaves and insects that make up their diet, the researchers found. The chimps鈥 shifts between hobnobbing and loner lifestyles were also important.
A study finds that frequent social interactions like these can help maintain a healthy gut microbiome.
Photo credit: Photo by Steffen Foerster, 老牛影视
Gut bacteria likely pass from chimp to chimp during grooming, mating or other forms of physical contact, or when they inadvertently step where other chimps have pooped, said co-author Anne Pusey, chair of Duke鈥檚 department of evolutionary anthropology.
The mix of bacteria in the animals鈥 bowels was just as similar between unrelated individuals as it was between mothers and offspring, the researchers found. This was surprising because infants pick up their first microbiomes from their mother when they pass through her birth canal. The findings suggest that, over a lifetime, social interactions with other chimps are just as important for gut microbial diversity as initial exposure from mom.
Scientists don鈥檛 yet know if social networks help maintain gut microbiome diversity in humans. 鈥淥ne of the main reasons that we started studying the microbiomes of chimpanzees was that it allowed us to do studies that have not or cannot be done in humans,鈥 said study co-author Howard Ochman of the University of Texas at Austin. 鈥淚t鈥檚 really an amazing and previously underexploited resource.鈥
Further studies are needed to determine how individual fluctuations in chimpanzee gut microbiome diversity impact their health, Moeller said.
Other authors include Michael Wilson of the University of Minnesota and Beatrice Hahn at the University of Pennsylvania's Perelman School of Medicine.
This research was supported by grants from the National Institutes of Health (AI58715 and GM101209) and the National Science Foundation (2011119472, 1407133, IOS-LTREB-1052693). The full text of the study can be the university's online repository of open-access research.