Effects of Glycoprotein from Periplaneta americana on the Growth and Metabolites of Two Probiotic Bacteria

Objective: The study aimed to investigate the effects of Periplaneta americana glycoprotein (PAG) on the growth and metabolites of Lactobacillus plantarum and Bifidobacterium adolescentis. Methods: With inulin as a positive control, the probiotic bacteria were cultured in medium containing different concentrations of PAG (MRS medium with PAG concentrations of 0.5, 1.0, 2.0, and 4.0 mg/mL, respectively. TPY medium with PAG concentrations of 1.0, 2.0, 4.0, and 8.0 mg/mL, respectively) to determine the OD₆₀₀ and pH, and the contents of lactic acid, short-chain fatty acid (SCFA, snamely acetic acid, propionic acid and butyric acid) in the bacterial solution. Results: The growth of Lactobacillus plantarum was greatest when the concentration of PAG reached 1.0 mg/mL, while Bifidobacterium adolescentis grew best with a PAG concentration of 2.0 mg/mL. The OD₆₀₀ value, production of lactic acid and SCFAs of Lactobacillus plantarum solution at 1.0 mg/mL PAG were higher than those of inulin, while the pH value was significantly lower. In the bacterial solution of Bifidobacterium adolescentis with 2.0 mg/mL PAG, the values of OD₆₀₀ and the production of propionic acid and butyric acid increased compared to the same concentration of inulin, the lactic acid production was better than that of inulin at 12 h, the acetic acid production was better than that of inulin at 24 h, and the pH value decreased, indicating that PAG and inulin had different effects on promoting Bifidobacterium adolescentis to produce lactic acid and SCFAs. Conclusion: The PAG could promote the proliferation and organic acid production of Lactobacillus plantarum and Bifidobacterium adolescentis, and the effect was better than that of inulin.