Lactobacillus sakei ADM14 Induces Anti-Obesity Effects and Changes in Gut Microbiome in High-Fat Diet-Induced Obese Mice

Abstract

The aim of our study was to evaluate the anti-obesity effects of Lactobacillus sakei (L. sakei) ADM14 administration in a high-fat diet-induced obese mouse model and the resulting changes in the intestinal microbiota. Prior to in vivo testing, L. sakei ADM14 was shown to inhibit adipogenesis through in vitro test and genetic analysis. Subsequently, mice were orally administered 0.85% saline supplemented or not with L. sakei ADM14 to high-fat diet group and normal diet group daily. The results showed that administration of L. sakei ADM14 reduced weight gain, epididymal fat expansion, and total blood cholesterol and glucose levels, and significantly decreased expression of lipid-related genes in the epididymal fat pad. Administration of L. sakei ADM14 showed improvement in terms of energy harvesting while restoring the Firmicutes to Bacteroidetes ratio and also increased the relative abundance of specific microbial taxa such as Bacteroides faecichinchillae and Alistipes, which are abundant in non-obese people. L. sakei ADM14 affected the modulation of gut microbiota, altered the strain profile of short-chain fatty acid production in the cecum and enhanced the stimulation of butyrate production. Overall, L. sakei ADM14 showed potential as a therapeutic probiotic supplement for metabolic disorders, confirming the positive changes of in vivo indicators and controlling gut microbiota in a high-fat diet-induced obese mouse model.

Keywords: Lactobacillus sakei; anti-obesity; gut microbiome; probiotics.

Figure 1

Adipogenesis inhibitory effect of L. sakei ADM14 in preadipocyte 3T3-L1 cells. (A) 3T3-L1 cells were treated with 1, 10, 50, and 100 μg/mL of L. sakei ADM14 extract to differentiate adipocytes for 6 days. Lipid accumulation was assessed by Oil Red O staining. (B) Oil Red O–stained 3T3-L1 cells were quantified. Stained cells were resolved with isopropanol, and the extracted dye was measured at 520 nm. (C) Effect of L. sakei ADM14 extract on cell viability. (D) L. sakei ADM14 suppressed the expression of adipocyte markers in 3T3-L1 cells. PPARγ, peroxisome proliferator-activated receptor-γ; C/EBPα, CCAAT-enhancer-binding protein-α; aP2, adipocyte protein 2; CD36, cluster of differentiation 36; FAS, fatty acid synthase. Data are means ± SEM. Significant differences compared with Ctrl (control), * p < 0.05, ** p < 0.01.

Figure 2

Effect of L. sakei ADM14 on high-fat diet-induced obese mouse model and changes in biomarkers. (A) Weight change of experiment mice groups for 10 weeks. (B) Total weight gain for each group after 10 weeks. (C) Food efficiency ratio over 10 weeks for each group. (D) Total caloric intake over 10 weeks for each group. (E) Organ weights of mice in each group after sacrifice. (F) Serum total cholesterol concentration. (G) Serum HDL (high density lipoprotein) concentration. (H) Serum LDL (low density lipoprotein) concentration. (I) Serum fasting glucose concentration. Results are shown as mean ± SEM (n = 5). Significant differences between HD and ND groups are indicated as # p < 0.05, ## p < 0.01. Significant differences between HD and HDA groups are indicated as * p < 0.05, ** p < 0.01.

Figure 3

Effect of L. sakei ADM14 on gene expression in the epididymal fat pads. (A) The mRNA expression levels of PPARγ, C/EBPα, aP2, CD36, and FAS as measured by quantitative real-time polymerase chain reaction. (B) Effect on expression of anti-inflammatory genes measured by quantitative real-time polymerase chain reaction. PPARγ, peroxisome proliferator-activated receptor-γ; C/EBPα, CCAAT-enhancer-binding protein-α; aP2, adipocyte protein 2; CD36, cluster of differentiation 36; FAS, fatty acid synthase; TNFα, tumor necrosis factor alpha; MCP-1, monocyte chemotactic protein 1; IL-6, interleukin-6. Results are shown as mean ± SEM (n = 5). Significant differences between HD and ND groups are indicated as # p < 0.05, ## p < 0.01. Significant differences between HD and HDA groups are indicated as * p < 0.05, ** p < 0.01.

Figure 4

Effect of L sakei ADM14 on taxonomic composition. (A) Cecal microbiota composition of groups is shown by generalized UniFrac principal coordinates analysis (PCoA). (B) Unweighted Pair Group Method with Arithmetic Mean (UPGMA) clustering. The distance calculated by generalized UniFrac. (C) The relative abundance of the cecal microbiota at the phylum, class, and family levels. n = 5 per group. The nonparametric Wilcoxon signed rank test for paired data and Mann–Whitney U test for unpaired data were used.

Figure 5

The relative abundance of specific bacteria in the cecum. (A) Bacteroidetes, Firmicutes, and Firmicutes to Bacteroidetes ratio. (B) Specific bacteria of important taxa in the human gut. The nonparametric Wilcoxon signed rank test for paired data and Mann–Whitney U test for unpaired data were used. Significant differences are indicated as * p < 0.05, ** p < 0.01.

Figure 6

Concentrations of short-chain fatty acids (SCFAs) from cecal contents. (A) Acetate concentration, (B) propionate concentration, (C) butyrate concentration. SCFAs were measured by gas chromatograph. Result are shown as mean ± SEM (n = 4). Significant differences are indicated as * p < 0.05, ** p < 0.01.