Early life gut microbial development is known to have a large impact on later life health in humans and other model organisms. Now there is solid evidence from a recent research study that mothers can influence this process, both before and after weaning. Although we’re not 100% certain how mothers do this, one possible explanation is that they transfer specific bacteria to their offspring.
Future studies will examine how differences in the gut microbiome during infancy influence other aspects of development, such as growth and the maturation of the immune system.
Scientists published a study in Current Biology of wild geladas (a nonhuman primate that lives in Ethiopia) that reportedly provides the first evidence of clear and significant maternal effects on the gut microbiome both before and after weaning in a wild mammal. This finding (“Maternal effects on early-life gut microbiota maturation in a wild nonhuman primate”) suggests the impact of mothers on the offspring gut microbiome community extends far beyond when the infant has stopped nursing.
A research team co-led by Stony Brook University anthropologist Amy Lu, PhD, and biologists Alice Baniel, PhD, and Noah Snyder-Mackler, PhD, at Arizona State University, came to this conclusion by analyzing one of the largest datasets on gut microbiome development in a wild mammal.
“Early-life microbial colonization is an important process shaping host physiology, immunity, and long-term health outcomes in humans. However, our understanding of this dynamic process remains poorly investigated in wild animals, where developmental mechanisms can be better understood within ecological and evolutionarily relevant contexts,” the investigators wrote.
“Using one of the largest developmental datasets on a wild primate—the gelada (Theropithecus gelada)—we used 16S rRNA amplicon sequencing to characterize the gut microbiota maturation during the first three years of life and assessed the role of maternal effects in shaping offspring microbiota assembly. In contrast to recent data on chimpanzees, postnatal microbial colonization in geladas was highly similar to humans: microbial alpha diversity increased rapidly following birth, followed by gradual changes in composition until weaning.
Dietary changes served as main drivers
“Dietary changes associated with weaning (from milk- to plant-based diet) were the main drivers of shifts in taxonomic composition and microbial predicted functional pathways. Maternal effects were also an important factor influencing the offspring gut microbiota. During nursing (<12 months), offspring of experienced (multi-time) mothers exhibited faster functional microbial maturation, likely reflecting the general faster developmental pace of infants born to these mothers. Following weaning (>18 months), the composition of the juvenile microbiota tended to be more similar to the maternal microbiota than to the microbiota of other adult females, highlighting that maternal effects may persist even after nursing cessation.
“Together, our findings highlight the dynamic nature of early-life gut colonization and the role of maternal effects in shaping this trajectory in a wild primate.”
“Early life gut microbial development is known to have a large impact on later life health in humans and other model organisms,” said Lu, associate professor in the department of anthropology at Stony Brook University. “Now we have solid evidence that mothers can influence this process, both before and after weaning. Although we’re not 100% certain how mothers do this, one possible explanation is that they transfer specific bacteria to their offspring.”
The research team used high throughput DNA sequencing to identify and characterize the bacteria residing in the guts of young geladas and identified 3,784 different genetic strains of bacteria belonging to 19 phyla and 76 families. However, this diversity was not equally distributed across the developmental spectrum: similar to what is seen in humans, younger infants had the least diverse microbial communities that gradually became more diverse as they got older.
These changes reflected what the infant was eating, specifically when they switched from consuming milk to consuming more solid foods. These diet-focused bacteria actually help infants process foods, e.g., milk glycans, which cannot be digested without the help of bacteria.
However, it was the team’s findings of strong maternal effects on the infant gut microbiome both before and after weaning that were the most groundbreaking.
“Infants of first-time moms showed slower development of their gut microbiota, meaning that their guts were specialized toward milk digestion for longer compared to kids from other moms. This may put offspring of newer moms at a slight developmental disadvantage,” said Baniel. “In addition, even after infants were weaned, their microbiome community was more similar to mom’s than to other adult females in the population, suggesting that moms may be sharing microbes with their offspring.”
According to Snyder-Mackler, “these early life changes might have far-reaching consequences—impacting the health and survival of these offspring once they become adults.”
Future work from this research team will focus on examining how differences in the gut microbiome during infancy influence other aspects of development, such as growth, the maturation of the immune system, or the pace of reproductive maturation. Because they are continuing to study the same infants as they age, they expect to eventually be able to link the infant gut microbiome and the early-life maternal effects to health, reproduction, and survival in adulthood.
