Synergistic Effects of Heat-Killed Kefir Paraprobiotics and Flavonoid-Rich Prebiotics on Western Diet-Induced Obesity

Abstract

The synergistic anti-obesity effect of paraprobiotic heat-killed lactic acid bacteria (HLAB) and prebiotics has not been studied. To determine the anti-obesity properties of prebiotic polyphenol-rich wine grape seed flour (GSF) and paraprobiotic HLAB, C57BL/6J mice were administered a high-fat and high-fructose diet (HFFrD) with 5% microcrystalline cellulose (CON), HFFrD supplemented with 2.5% GSF, HFFrD with orally administered HLAB, or HFFrD with a combination of GSF and orally administered HLAB (GSF+HLAB) for 8 weeks. Compared with the CON group, the GSF and HLAB groups both showed significant reductions in HFFrD-induced body weight gain and adipose tissue weights (p < 0.05). Interestingly, combined supplementation with GSF and HLAB revealed statistically significant synergistic effects on body weight gain, visceral adiposity, and plasma triacylglycerol concentrations (p < 0.05). The synergistic action was significantly related to a decreased adipocyte gene expression in fatty acid synthesis and inflammation metabolism. In conclusion, the combination of prebiotic GSF and paraprobiotic kefir HLAB is potentially useful, as natural food ingredients, in the prevention of obesity and obesity-related diseases, especially for immunocompromised individuals.

Keywords: heat-killed lactic acid bacteria; obesity; paraprobiotics; prebiotics; wine grape seed flour.

Figure 1

Effect of 2.5% wine grape seed flour (GSF) and heat-killed kefir lactic acid bacteria (HLAB) on C57BL/6J mice fed a high-fat and high-fructose diet (HFFrD) containing 5% microcrystalline cellulose (CON), 2.5% wine grape seed flour (GSF), 2.5% GSF with orally administered heat-killed kefir lactic acid bacteria (GSF+HLAB), and orally administered heat-killed kefir LAB (HLAB) for 8 weeks. (A) Body weight gain, (B) total energy intake, (C) adipose tissue weight, (D) Hematoxylin and Eosin (H&E) staining of adipose tissue. Data are expressed as mean ± SE; n = 8–10/group. Values not sharing a common letter differed significantly at p < 0.05.

Figure 2

Effect of 2.5% wine grape seed flour (GSF) and heat-killed kefir lactic acid bacteria (HLAB) on gene expression levels in the adipose tissues of mice fed a high-fat and high-fructose diet (HFFrD) containing 5% microcrystalline cellulose (CON), 2.5% wine grape seed flour (GSF), 2.5% GSF with orally administered heat-killed kefir lactic acid bacteria (GSF+HLAB), and orally administered heat-killed kefir LAB (HLAB) for 8 weeks. Data are expressed as mean ± SE; n = 6/group. Values not sharing a common letter differed significantly at p < 0.05.

Figure 3

Inhibitory effects of cellular exopolysaccharide (EPS)s of heat-killed kefir lactic acid bacteria with increasing concentrations (0.01, 0.1, 0.2 mg/mL) on relative Oil red O staining content in 3T3-L1 adipocytes after differentiation (day 6). The cells differentiated in the presence of the heat-killed kefir LAB (HLAB) for 6 days after confluence. Values of the intracellular Oil red O staining of the treated cells are presented as percentages relative to the values of the untreated control. Data are expressed as mean ± SEM, * indicates a significant difference (p < 0.05) compared to control, # data were not measured.