Bifidobacterium animalis subsp. lactis BB-12 Has Effect Against Obesity by Regulating Gut Microbiota in Two Phases in Human Microbiota-Associated Rats

Abstract

Bifidobacterium animalis subsp. lactis BB-12 (BB-12) is an extensively studied probiotics species, which has been reported to improve the human gut microbiota. This study aimed to confirm the effects of BB-12 on high-fat diet (HFD)-induced gut microbiota disorders. The probiotic BB-12 was consumed by human microbiota-associated rats and changes in gut microbiota were compared using next generation sequencing of the fecal samples collected from the normal chow group, the HFD group, and the BB-12-supplemented group. The enterotypes switched from Prevotella dominant to Akkermansia dominant as a result of switching diet from normal chow to HFD. BB-12 conferred protection on the gut microbiota composition of the rats by increasing the abundance of Prevotella and decreasing the abundance of Clostridium, Blautia, and Bacteroides in 0-3 weeks. In addition, Prevotella-dominant enterotype was maintained, which provides improve obesity effects. A decrease in body weight and the Firmicutes/Bacteroidetes ratio were also observed at week 3. While in 4-8 weeks, the enrichment of short-chain fatty acids-producing bacteria such as Eubacterium and Parabacteroides and probiotics such as Bifidobacterium was observed. The results revealed that BB-12 against obesity by regulating gut microbiota in two phases. After a short-term intervention, BB-12 supplementation suppressed the transition from the healthy to obesity state by protecting Prevotella-dominant enterotype, whereas after a long-term intervention, BB-12 ameliorates obesity by enriching beneficial bacteria in the gut.

Keywords: Bifidobacterium animalis subsp. lactis BB-12; Prevotella; enterotypes; gut microbiota; obesity.

Figure 1

Group information of HMA-SD rat models. After 5 days of adaptation, human fecal suspension was intragastrically administered every 2 days three times to build the HMA-rats model. Then, the 16 HMA-SD rats were randomly divided into 3 groups for a 8-week trial. The normal chow (NC) group, 8 weeks of NC and daily administration of sterile water gavage, as negative control; the high-fat diet (HFD) group, 8 weeks of HFD and sterile water gavage; the BB-12 group, 8 weeks of HFD and BB-12 gavage. HMA-SD, human microbiota-associated-Sprague-Dawley; SW, sterile water; TKM, Tibet kefir milk; 16S rRNA, 16S ribosomal RNA. Yellow triangle up solid, sampling sites for 16S rRNA sequencing; red triangle up solid, sampling sites for serum lipid profile.

Figure 2

Gut microbiota taxonomic profiles. (A) Relative abundances of microbial composition at the phylum level and relative abundances of top 10 genera; 0–8 represents 0–8 weeks and C represents colonic content samples. (B) Absolute abundances of microbial taxa (genera level) compared between the NC, HFD, and BB-12 groups. Different letters (a or b) above the box indicate significant difference (p < 0.05) or (p < 0.01).

Figure 3

Correlation analysis between body weight and Firmicutes/Bacteroidetes ratio. The graph shows arbitrary data for the NC group (gray circles and density curves), the HFD group (light yellow circle and density curves), and the BB-12 group (light blue circle and density curves).

Figure 4

Principal component analysis (PCA) of bacterial community composition based on relative abundances of 16S rRNA from 159 samples. (A–C) Show the NC, HFD, and BB-12 group, respectively; letters A–I in the figures represent the fecal samples from 0 to 8 weeks and J represents colonic content samples. (D–L) represent the fecal samples at 0–8 weeks, respectively and (M) represented the colonic contents samples; the numbers 1–3 in (D–M) represent the NC, HFD, and BB-12 group, respectively.

Figure 5

Linear discriminant analysis (LDA) effect size (LEfSe) analysis of bacterial community composition based on relative abundances of 16S rRNA from 16 colonic contents samples. (A) LEfSe cladogram representing different abundant taxa; and (B) LDA scores as calculated by LEfSe analysis. Only taxa with LDA scores of more than 2 were presented.

Figure 6

Enterotype (ET) analysis based on the genus-level bacterial composition of the gut microbiota. (A) 159 samples were divided into two different ETs; (B,C) represent the relative abundance of Prevotella and Akkermansia in each ETs, respectively; (D) represents the Firmicutes/Bacteroidetes ratio into two different ETs; (E) distribution of ETs by each group; (F) represents the body weight in different ETs; (G) Manhattan plot showing OTUs being enriched in ET1 or ET2; each dot or triangle represents a single OTU. OTUs enriched in ET1 or ET2 are represented by filled or empty triangles, respectively (FDR adjusted p < 0.05). OTUs are arranged in taxonomic phylum. OTUs, operational taxanomic units; FDR, false discovery rate; CPM, counts per million; ET1, enterotype 1; ET2, enterotype 2. ^*p < 0.05; ^**p < 0.01; ^***p < 0.001.

Figure 7

Prediction of the function of bacterial communities based on 16S rRNA sequencing. (A) The third level of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway was shown in the heatmap. (B) Analysis for the KEGG pathway (level 2) using LEfSe.

Figure 8

Heatmap of the Pearson's rank correlation coefficient between the KEGG pathway (level 2) and gut microbiota.