Your pet pooches’ microbes may make you more caring

Dogs may be man’s best friend, but what if they boost our well-being by altering our microbiome? A series of experiments in mice suggests that dog owners have a unique make-up of bacterial species that encourage empathetic and social behaviours.With dogs typically topping popular pet lists, Takefumi Kikusui at Azabu University in Japan wanted to understand whether the animals change our gut microbiome in a way that prompts good well-being.To explore this, the researchers analysed surveys where caregivers of 343 adolescents, who were aged 12 to 14 and lived in Tokyo, reported on various aspects of their social behaviour, such as how often they felt lonely or struggled to get on with their peers.

The surveys also revealed that about a third of the adolescents had a pet dog.The team found those with dogs ranked as less socially withdrawn and behaved less aggressively than non-dog-owners, on average.Saliva samples also revealed that several species of Streptococcus bacteria were more abundant in the dog owners, which has been linked to reduced depressive symptoms.“If you’re playing with a dog a lot, you’re going to have a lot of exposures to the microbes the dog has, from licks [and] them jumping up on you,” says Gerard Clarke at University College Cork, Ireland.

The team then transplanted oral microbes from three dog owners and three non-dog-owners into the stomachs of germ-free mice. Over the next few weeks, the team had the animals carry out a series of behavioural tests. In one, the mice were placed in a cage with another mouse that was trapped in a tube. The mice that received transplants from dog owners chewed the tube and poked their nose through holes in it significantly more often than those that received transplants from non-dog-owners.This suggests that the former mice had more empathy and were trying to help, says Kikusui. In another test, these same mice sniffed at an unfamiliar mouse in their cage more often than the other group, which suggests they were more social, says Clarke.(Carissa Wong, New Scientist, distributed by Tribune Content Agency)