title: High-sucrose diet, Control dose 3
design: Pups were kept in clean cages with sterilized bedding. Caecum samples from these pups were collected at PND21 and PND80 in sterilized tubes, and they were immediately stored at -80oC. DNA from caecal samples were extracted by QIAamp Stool DNA extraction kit. PCR enrichment for each sample was carried out with fusion primers targeting the 16S rRNA V4 hypervariable region. The resulting PCR products were purified with Beckman Coulter Agencourt AMPure XP beads and subjected to amplicon library preparation. Prior to sequencing, the quality and quantity of the constructed libraries were assessed with Agilent 2100 Bioanalyzer. Samples that passed the QC step were sequenced.