“Considering its excellent antimicrobial activity, we hypothesized that B. laterosporus could regulate gut microbiota dysbiosis and ameliorate excessive fat deposition,” wrote the team of Chinese agricultural and animal nutrition scientists.
“To confirm this hypothesis, we isolated a novel B. laterosporus strain BL1 from a healthy earthworm intestine and investigated [its] effects on obesity in HFD-fed mice for the first time, with particular emphasis on the potential role of intestinal flora modulation as a novel preventive approach.”
The research was supported by the Research and Demonstration and Promotion Project of Efficient Breeding Technology and Intelligent Equipment of Breeding Boars, the Low Carbon Agriculture Neutralization Research Center, the People’s Livelihood Science and Technology Project of Guangzhou Science and Technology Bureau and the Rural Revitalization Strategy Special Project of Guangdong Province.
In search of novel strains for obesity
The researchers noted that widely available probiotics Lactobacillus and Bifidobacteria have shown beneficial effects on lipid metabolic disorders including obesity and nonalcoholic fatty liver disease through regulation of energy metabolism, inflammatory response and intestinal barrier function.
“Despite these positive outcomes, a recent systematic study showed that the species of probiotics that are effective in the prevention or treatment of adiposis are scarce, and limited probiotics produce a discrete benefit in clinical applications,” they added. “For this reason, there is an urgent demand to identify novel strains with anti-obesity properties and the functional mechanisms involved in their actions.”
Previous studies show that B. laterosporus produces various antimicrobial substances including polyketides, non-ribosomal peptides, antibiotics and chitinase, resulting in broad-spectrum antimicrobial activity. In 2013, the Chinese Ministry of Agriculture and Rural Affairs called for the strain's inclusion in the catalog of feed additives, but the study pointed to a paucity of research into its beneficial effects in livestock and poultry. The research team’s own pre-experiment in a porcine model suggested potential to improve abnormal fat deposition, but the underlying mechanism remained unclear.
Study details
The present study randomly assigned 40 five-week-old C57BL/6 male mice into four equal groups – fed either a control diet, high-fat diet, high-fat diet plus B. laterosporus BL1 or a high-fat diet plus supernatant of B. laterosporus BL1 for eight weeks.
Beyond evaluating the effects on obesity, the researchers assessed fat deposition, serum lipids, insulin resistance, chronic inflammation, intestinal flora composition and colonic short-chain fatty acids (SCFAs). It also explored the correlation between key gut microbial taxa and SCFAs/obesity-related parameters.
“The results showed that prophylactic B. laterosporus BL1 treatment reduced body weight gain by 41.26% in comparison to the HFD group, and this difference was accompanied by a reduction in body fat mass and the weight of inguinal white adipose tissues and epididymal white adipose tissue (−33.39%, −39.07%, and −43.75%, respectively),” the findings showed.
Improvements in lipid profile, insulin resistance and chronic inflammation in the B. laterosporus BL1 group were associated with the regulation of gene expression related to lipid metabolism and enhancement of brown adipose tissue thermogenesis.
In particular, B. laterosporus BL1 significantly improved HFD-induced gut flora dysbiosis, reversing the relative abundance of Bacillota (formerly known as Firmicutes) and Bacteroidota and increasing the relative abundance of bacteria that produce SCFAs. The supernatant test group, however, experienced no obvious changes in gut microbiota.
Source: Frontiers in Nutrition
“Brevibacillus laterosporus BL1, a promising probiotic, prevents obesity and modulates gut microbiota in mice fed a high-fat diet”
doi: 10.3389/fnut.2022.1050025
Authors: Guangying Weng, et al.
