Probiotics-fermented blueberry juice prevents obesity and hyperglycemia in high fat diet-fed mice in association with modulating the gut microbiota

Blueberry dietary interventions have demonstrated remarkable potential against obesity and type 2 diabetes mellitus. However, the effects of fermented blueberry juice on metabolic syndrome, the gut microbiota, and insulin resistance have not yet been reported. This study aimed to investigate the potential of fermented blueberry juice against obesity, hyperglycemia, and the gut microbiota dysbiosis in high fat diet (HFD)-fed mice. Study findings revealed that supplementation with fresh blueberry juice (BBJ), fermented blueberry juice with homemade probiotics starter (FBJ) or commercial starter (CFBJ) significantly decreased fat accumulation and low density lipoprotein cholesterol (LDL-C) levels in HFD-fed mice. FBJ showed relatively more potency to reduce body weight compared to BBJ and CFBJ. The percentage increase in the body weight of the FBJ group was almost the same as that in the normal chow diet (NCD) group, and approximately 10% lower in comparison to BBJ and CFBJ groups. Overall, all blueberry juices significantly ameliorated hyperlipidemia and insulin resistance in HFD-fed mice. Moreover, the dietary interventions of the BBJ, FBJ, and CFBJ for 17 weeks significantly improved the community richness and diversity of the gut microflora along with an altered structure in HFD-fed mice group. FBJ treated mice group showed relatively a low abundance of Firmicutes, obesity-related bacteria (Oscillibacter and Alistipes), and a high abundance of lean bacteria (Akkermansia, Barnesiella, Olsenella, Bifidobacterium, and Lactobacillus) compared to HFD mice group. Furthermore, BBJ and FBJ treatments regulated liver mRNA and protein expression levels involved in lipid and glucose metabolism. This study inferred that fermented blueberry juice could be used as a functional food to prevent the modern pandemics i.e., obesity and insulin resistance.