Lysinibacillus macroides 38352 Isolated from Traditional Chinese Fermented Foods: A Dual Effect on Ochratoxin A Detoxification and Immune Suppression Alleviation
Description
Ochratoxin A (OTA) poses a persistent threat to global food safety and livestock health. We isolated three OTA-degrading bacterial strains from 28 types of traditional Chinese fermented foods. Among them, Lysinibacillus macroides 38352 exhibited the highest degradation efficiency, removing 51.4% of 2.5 μg/mL OTA within 72 hours at 37 °C, with further increases observed over time. Mechanistic analysis revealed that the degradation was mediated not by cell surface adsorption but by secreted metabolites generated through active cellular metabolism. The strain also demonstrated excellent probiotic properties, including tolerance to pH 2–12 and 0.2% bile salts, sensitivity to 15 antibiotics (indicating no resistance), and no pathogenicity in mice. Notably, oral administration of L. macroides 38352 significantly reversed OTA-induced immunosuppression, enhancing vaccine-induced specific IgG, neutralizing antibody titers, and cytokine levels (IL-1β, IL-4, IL-12, IL-17, and IFN-γ), while also reducing inflammatory damage and improving growth performance in OTA-exposed broilers. Sequence analysis of strains 38351, 38352, and 38362. Figure 1. Isolation of the OTA-degrading strains. Colony and cell morphology of the isolated strains. (A) Strain 38351. (B) Strain 38352. (C) Strain 38362. (D) Removal ratio of OTA by strains. (* p < 0.05, ** p < 0.01, *** p < 0.001). Figure 2. Phylogenetic tree of the isolated 38351, 38352 and 38362 and related taxa. (A) Phylogenetic tree analysis of isolates based on partial 16S rRNA gene sequences. (B) Phylogenetic tree analysis of isolates based on partial gyrB gene sequences. Figure 3. Degradation properties of OTA by isolated strains. (A) Growth curve of isolated strain 38352. (B) Degradation rate of OTA by different cell components. OTA degradation ability of strain 38352: (C) Effect of different cell concentrations, (D) effect of culture time, and (E) culture temperature. (* p < 0.05, ** p < 0.01, *** p < 0.001). Figure 4. Results of body weight change monitoring. (A) Line chart of body weight change before poison attack. (B) Histogram of body weight change after poisoning. Figure 5. Specific IgG antibody level in chicken serum on Day 7 and Day 14 after immunization, as well as 7 days after subsequent challenge with C. perfringens. Figure 6. Gene transcription of immune-related cytokines in (A) jejunum and (B) cecal tonsil. Data were presented as means ± SD (* p < 0.05, and ** p < 0.01). Figure S1. (A) Results of body weight change in mice. (B) Results of the mice autopsy from the strain 38352 group and the control group. Figure S2. Lesion score results of each experimental group. Table 1. Results of bacterial susceptibility test. Table S1 PCR primers sequences. Table S2. Probiotic properties of isolates.