Analysis of the V4 region of 16S rRNA gene amplified from DNA extracted from the colonic content of mice exposed to early life stress

Established behavioral models of ELS in rodents involving maternal separation (MS) have shown that adult animals, which were exposed to stress as pups, harbor different microbial populations. Given the time lapse between the stress exposure and microbial investigations, it is not known when these differences begin to manifest. It is also unknown whether differences documented in the microbiota of stressed animals are inherited from their mothers, which may also experience stress due to MS, or are due to endogenous factors within the offspring. Therefore, we used a mouse model of ELS involving MS with early weaning (MSEW) to address two objectives: (1) to determine the effect of MSEW on the neonate and adolescent microbiota and (2) to examine potential differences in dam microbiota due to MSEW that could be transmitted to their offspring. MSEW mice were subjected to maternal separation for 4 h per day on postnatal days (PDs) 2-5, and 8 h per day on PDs 6-16, and were subsequently weaned at PD17. Normally reared (NR) mice remained undisturbed with dams until weaning on PD21. All mice were maintained on standard chow (NIH-31; NSN 8710-01-005-8438) following weaning. Colonic microbial composition of MSEW and normally reared (NR) pups was examined via Illumina sequencing of the V4 region of the 16s rRNA gene at postnatal day PD2, PD10 and PD28 . Fecal microbiota of dams were also sequenced.