Fecal microbiota transplantation from Suncus murinus, an obesity-resistant animal, to C57BL/6NCrSIc mice, and the antibiotic effects in the approach

Abstract

Introduction: Important studies on the relationship of the intestinal microbial flora with obesity have uncovered profound changes in the composition of the gut microbiota in obese individuals. Animal studies successfully altered body phenotypes by fecal microbiota transplantation (FMT).

Methods: In this study, we analyzed the gut microbiome of Suncus murinus (S. murinus), a naturally obesity-resistant animal, and the changes of the gut flora of C57BL/6NCrSIc mice that received gut bacteria transplantation from S. murinus by 16S rRNA gene analysis method. And analyzed and discussed the possible impact of the use of antibiotics before transplantation on the outcome of transplantation.

Results: Our results showed no significant changes in body weight in the FMT group compared to the control (AB) group, but large fluctuations due to antibiotics. There was no change in blood lipid levels between groups before and after FMT. The gut microbiota of S. murinus were enriched in Firmicutes and Proteobacteria, while Bacteroidetes were not detected, and fewer OTUs were detected in the intestine gut in comparison to other mouse groups. Statistically significant differences in alpha diversity were observed between the FMT group and other groups. Furthermore, a beta diversity analysis indicated an apparent structural separation between the FMT group and other groups.

Conclusion: It was suggested that the gut flora of S. murinus was not well established in the gut trace of mice through FMT, and the administration of antibiotics before transplantation was an important factor affecting the overall composition of the gut flora. Although FMT of S. murinus failed to completely colonize the intestinal tract of the mice, it still had a certain effect on the establishment of the intestinal flora of the mice. The unpredictable effects of pre-transplantation antibiotics on the results of transplantation cannot be ignored.

Keywords: 16S rRNA; Suncus murinus; antibiotics; fecal microbiota transplantation; gut microbiota; obesity-resistant.

Figure 1

Schedule of antibiotic treatment period (Abx), fecal microbiota transplantation (FMT) and body weight measurements (BW). FMT, FMT group; AB, antibiotic group; Con, Control group.

Figure 2

The species rarefaction curve of each experimental group. This graph represents the numbers of observed species under different sequences numbers extracted randomly, Chao 1 (A), Observed species (B), and PD whole tree (C). Chao 1, Chao’s estimated richness; PD, Phylogenetic distance; Con, Control group; FMT, fecal microbiota transplantation group; AB, antibiotic group; DC, donor group.

Figure 3

Relative abundance ratio of the intestinal microbiome at the phylum level in each experimental group. Data are presented as the percentage of species, and the results were obtained using the Kruskal–Wallis test. Con, Control group; FMT, fecal microbiota transplantation group; AB, antibiotic group; DC, donor group.

Figure 4

Relative abundance ratio of the intestinal microbiome at the genus level in each experimental group. Data are presented as the percentage of species, and the results were obtained using the Kruskal–Wallis test. Con, Control group; FMT, fecal microbiota transplantation group; AB, antibiotic group; DC, donor group.

Figure 5

A Cluster analysis based on the Unifrac distance matrix (A) and on the weighted Unifrac distance (B) in groups at the phylum and genus levels. Control group: Con1, Con2, Con3, Con4, Con5. Antibiotic group: AB1, AB2, AB3, AB4, AB5. Decal microbiota transplantation group: FMT1, FMT2, FMT3, FMT4, FMT5. DC group: DC1, DC2, DC3, DC4, DC5.

Figure 6

Comparisons of the alpha diversity, Chao 1 (A) and Shannon (B) index. The same letter indicates that there was no significant difference between the groups; a different letter indicates a statistically significant difference between the groups. Con, Control group; FMT, fecal microbiota transplantation group; AB, antibiotic group; DC, donor group.

Figure 7

The principal coordinate analysis (PCoA) of the bacterial community structures of mice and donor gut microbiomes based on the Bray-Curtis (weighted UniFrac) distance. (A): The analysis of similarity (ANOSIM) of the four groups. Con, Control group; FMT, fecal microbiota transplantation group; AB, antibiotic group; DC, donor group.

Figure 8

Heatmap of differential species abundance clustering between Con and AB groups (A), Con and FMT groups (B), and AB and FMT groups (C). The heatmap shows the hierarchical clustering of samples based on the relative abundance of fecal microbiota in the FMT, AB and Con groups. The relative values in the heatmap (after normalization), depicted by color, indicate the degree of aggregation or content of bacterial species among samples at the genus level. The color gradient from blue to red indicates low to high relative abundance, respectively. The vertical clustering indicates the similarity in the richness of different species among different samples. The closer the distance between two species, the shorter the branch length, indicating greater similarity in richness between the two species. Horizontal clustering indicates the similarity of species richness in different samples. Similarly, the closer the distance between two samples, the shorter the branch length, indicating greater similarity in richness of species between the two samples. Con, Control group; FMT, fecal microbiota transplantation group; AB, antibiotic group.

Figure 9

Venn diagram of shared and unique taxa at the genus level among Con, AB and FMT groups. The numbers of shared and unique taxa in the three pairwise comparison groups are shown based on the operational taxonomic units. Con, Control group; FMT, fecal microbiota transplantation group; AB, antibiotic group; DC, donor group.