The hypoglycemic and antioxidant activities of Lactobacillus plantarum FPS 2520 and/or Bacillus subtilis N1 fermented soybean meal (SBM) in rats fed a high-fat diet (HFD) were investigated by assessing plasma glucose levels, insulin resistance, and oxidative stress-induced organ damage. Supplementation with FPS 2520- and/or N1-fermented SBM (500 and 1000 mg/kg of body weight per day) to HFD-induced obese rats for 6 weeks significantly down-regulated the concentration of plasma glucose during the oral glucose tolerance test (OGTT), as well as the concentration of fasting plasma glucose, insulin, and the value of the homeostasis model assessment of insulin resistance (HOMA-IR). In addition, plasma and hepatic levels of malondialdehyde (MDA) were alleviated in rats fed fermented SBM, especially SBM fermented by mixed strains. Moreover, fermented SBM treatment reduced HFD-exacerbated increases in plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and uric acid levels. Based on these results, we clearly demonstrate the effect of fermented SBM on improving insulin resistance and oxidation-induced organ damage. Therefore, it is suggested that fermented SBM has the potential to be developed as functional foods for the management of obesity-induced hyperglycemia and organ damage.
Keywords: Bacillus; Lactobacillus; antioxidant protection; fermented soybean meal; functional food; hypoglycemia; insulin resistance; probiotics.