The early life microbiota mediates maternal effects on offspring growth in a nonhuman primate

Early-life gut microbiota assembly patterns are conserved between laboratory and wild mice

“…During this time, the microbiota increased in alpha diversity, changed in taxonomic composition, and became more homogenous in composition among individuals. These patterns resemble those of gut microbiota maturation reported for humans and wild gelada baboons 20,25,27,58,59 but contrast those reported in a study of wild chimpanzees, where richness declined during early life 26 . As previously documented in humans 20,60 , anaerobic bacteria also increased in relative abundance during early life, likely because they are best adapted to the increasingly anoxic conditions of the developing gut.…”

“…The gut microbiota's stereotypical trajectory of maturation has been well-characterised in humans, but in other mammals and especially in wild contexts, it is far less well-known. Studies of gut microbiota assembly in wild primates have reported somewhat conflicting patterns, with research on gelada baboons finding patterns that largely reflect those in humans 24,25 , while a study in wild chimpanzees reported declining microbiota richness during early life 26 . This suggests the broad patterns of microbiota assembly observed in humans may not be universal among mammals, and may vary with host genetic background or environmental context.…”

The social microbiome: The missing mechanism mediating the sociality-fitness nexus?

“…Given that maternal vertical transmission shapes the trajectory of early life microbiome maturation, it will likely modulate offspring developmental outcomes. 78 Early life microbial colonization and diversification are known to influence infants’ growth and phenotypic development, 79 , 80 the maturation and education of the immune system, 17 as well as neurodevelopment, 81 thus leading to profound health and fitness consequences across the life course. 82 In humans, numerous clinical studies have shown how perturbations in the normal pattern of mother-offspring vertical transmission during the perinatal period (e.g., Caesarean section, maternal antibiotic use, or formula feeding) can translate into metabolic- and immune-associated disorders in offspring, that often persist during childhood and until adulthood, such as type 1 diabetes, obesity, IBD, or asthma.…”

“… 5 Recent studies in mammals have shown, for example, that maternal traits, such as parity (i.e., the number of times a female reproduced), are associated with differences in offspring’s GI composition and translates into variation in the speed of offspring’s GI microbiome maturation. 79 …”

“…Linking the composition of the social microbiome to host fitness requires longitudinal, individually centred data on social behaviors, parasitic and nutritional statuses, and immunological markers to test, for example, whether highly social individuals benefit from higher resistance to pathogen infections via the diversity or composition of their microbiome and if protective symbionts are also the ones that are socially acquired. Structural equation models (SEMs), such as path analysis 79 or mediation analysis, 93 can resolve complex multivariate relationships among a suite of interrelated variables and emerge as promising statistical tools to address whether the relationship between sociality and fitness is mediated significantly and directly or indirectly by the social microbiome. Such models would further allow researchers to assess the relative importance of the “chronic stress” hypothesis (e.g., measured by GCs concentration and/or immune markers) and the “social microbiome” hypothesis.…”