Microbiota Implicated in Poor Maternal Behavior and Neglect of Offspring

A new study led by Salk Institute scientists has identified a strain of E. coli that, when living in the guts of female mice, causes them to neglect their offspring. The findings were published in Science Advances.

"To our knowledge, this is the first demonstration that the intestinal microbiota is important for promoting healthy maternal behavior and bonding between mom and offspring in an animal model," says Janelle Ayres, senior author of the paper. "It adds to the ever-growing evidence that there's a gut-brain connection, and that microbes are important for regulating the behavior of the host that they're inhabiting."

In the current experiments, her team were investigated groups of mice that had a single strain of E. coli in their gut. They found that mice with one particular strain of E. coli, called O16:H48 MG1655, mothered offspring that had stunted growth. Further examination revealed that the mice were smaller because they were malnourished. "We found that the pups' behavior was normal, and the milk made by the mothers was of normal, healthy composition and was being produced in normal amounts," Ayres says. "We eventually figured out that being colonized with this particular bacteria led to poor maternal behavior. The mice were neglecting their pups."

Additional experiments revealed that the mice could be rescued from stunted growth, either by giving them a growth factor called IGF-1 or handing them off to foster mouse mothers that could take care of them properly. This confirmed that the cause of stunted growth was coming from the mothers' behavior rather than something in the pups themselves.