Pregnancy-related changes in microbiome are disrupted by obesogenic diet exposure: implications for offspring...

Pregnancy can alter gut microbiota composition, but effects of an obesogenic diet on both mother and offspring microbiome can be obscured by confounding factors. This study examined changes in gut microbiota composition prior to pregnancy, and across gestation and lactation in rat dams fed either a high-fat, high-sugar Cafeteria (Caf) diet or Chow. Microbiome development was assessed in male and female offspring weaned onto chow. Caf diet consumption during pregnancy increased weight gain and adiposity, with increased glucose and plasma leptin and lower folate and B12 levels indicating metabolic disturbance in dams. α- and β diversity measures in Caf-fed dams showed no change in Bacteroidetes and Firmicutes abundance across pregnancy compared with Chow dams, who showed reduced Firmicutes at gestation and mid-lactation. Offspring born to Caf versus Chow dams exhibited greater adiposity and plasma leptin at weaning (3 weeks); at 14 weeks these changes were only observed in males. Maternal Caf diet induced clear differences in β diversity in weanlings but not α diversity. Caf weanlings had lower plasma folate but higher B12 levels compared to chow counterparts. Maternal folate levels were positively associated with maternal and weanling gut microbiota, specifically OTU2 Romboutsia and OTU3_Lactobacillus relative abundance. SourceTracker analysis revealed similarities in the gut microbiota of Chow weanlings and maternal gut microbiota observed during lactation, whereas the microbiota of Caf weanlings was similar to the maternal gut microbiota during gestation. Maternal Caf diet had marginal effects on gut microbiota composition in adult offspring consuming regular chow.