Ontogenetic characteristics of the intestinal microbiota of Quasipaa spinosa revealed by 16S rRNA gene sequencing

To analyse the correlation between the intestinal microbiota (IM) and differential development of Quasipaa spinosa across different stages of metamorphosis, we focused on four key developmental periods (15 days post‐hatch [dph; Gosner stage, GS23], 60 dph [GS25], 90 dph [GS41] and 150 dph [GS25, GS41, GS42, GS46]) and used 16S rDNA amplicon sequencing. Results showed that IM diversity in Q. spinosa was related to life history. Specifically, there was a significant difference between the aquatic and terrestrial stages, and IM diversity increased with age. Proteobacteria, Bacteroidetes and Firmicutes were the dominant phyla in tadpoles, whereas Bacteroidetes, Proteobacteria, Firmicutes and Fusobacteria were the dominant phyla at the metamorphosis stages. The composition of the IM at different stages and ages varied considerably, but the changes were not substantial among different development stages at 150 dph. This was probably because age has a greater influence than growth factors, and host selective pressure increases with age. This study provides a theoretical reference for subsequent studies on the IM, as well as for the prevention of amphibian endogenous pathogenic microbial diseases. Significance and Impact of the Study: We investigated the intestinal microbiota (IM) of Quasipaa spinosa tadpoles at four key stages during metamorphosis using high‐throughput sequencing of the 16S rRNA gene. Our results showed that the composition of the IM at different development stages and different ages differed markedly, but the differences were not significant among different development stages at 150 days post‐hatch. These results indicate that the developmental stage and length of development significantly affect the IM composition of Q. spinosa.