The influence of maternal unhealthy diet on maturation of gut microbiota in rat offspring from weaning to 14 weeks of age

Background: The gut microbiota has significant impacts on host health. Diet has a well-established reciprocal relationship with gut microbiota composition. However, the influence of maternal consumption of healthy or unhealthy diets on the longitudinal maturation of gut microbiota in offspring are not well understood. To investigate this, we fed female rats a western-style, cafeteria diet (Caf) prior to and during mating, gestation and lactation. Male and female offspring were weaned onto chow or Caf diets, forming four offspring groups that were either maintained on their mother's diet (ChowChow, CafCaf groups) or switched to the other diet at weaning (ChowCaf, CafChow). Fecal microbial composition of dams and offspring were assessed longitudinally at 3, 7 and 14 weeks of age. Results: At weaning, offspring gut microbiota was significantly different from that of older siblings and dams, characterised by significantly reduced a diversity, and ß diversity profiles that clustered away from other groups. SourceTracker analyses showed increased Caf dam associated species in weaners' gut microbiota, regardless of maternal diet. After weaning (3 weeks), offspring gut microbiota came to resemble the mother's (adult-like) gut microbiota over time, with an increase in a diversity, reduced dissimilarity of ß diversity, and fewer altered OTUs between groups. Continuous consumption of Caf diet throughout pregnancy to postnatal early life (CafCaf) altered ß diversity of offspring gut microbiota compared with ChowChow group, however, the developmental trajectory of the offspring gut microbiota was consistent between ChowChow, CafCaf, ChowCaf and CafChow groups. Sex did not interact with the growth trajectory of offspring gut microbiota. Conclusions: Our study shows that the offspring gut microbiota community started maturing toward an adult-like gut microbiota when offspring were introduced to solid food. The developmental profiles of rat offspring gut microbiota are largely in agreement with previous human studies and implicate the cessation of lactation as an important trigger for early life gut microbiota development across species. The cessation of lactation and introduction of solid food is a critical window of offspring gut microbiota maturation.