Potential preventive role of lactic acid bacteria against Aflatoxin M₁ immunotoxicity and genotoxicity in mice

Abstract

Aflatoxin M₁ (AFM₁) is a mycotoxin produced by numerous Aspergillus species in pre- or post-harvest cereals and milk. Exposure to AFM₁ imparts potent economic losses in the livestock industry. Toxicologically, it also causes severe immune system problems. The aims of this study were to evaluate a new AFM₁-binding/degrading microorganism for biologic detoxification, to examine its ability to degrade AFM₁ in liquid medium, and to evaluate its potential for in vivo preventative effects against AFM₁-induced immunotoxicity and genotoxicity in mice. Lactobacillus plantarum MON03 (LP) isolated from Tunisian artisanal butter was found to display significant binding ability to AFM₁ in PBS (93%) within 24 h of incubation. Further, the LP was able to tolerate gastric acidity, bile salts, and adhere efficiently to Caco-3 cells in vitro. The in vivo study used Balb/c mice that received either vehicle (control), LP only (at 1 × 10⁹CFU/L, ∼1 mg/kg bw), AFM₁ (100 mg/kg bw), or AFM₁ + LP daily for 15 days (by gavage); two other groups received a single dose of colchicine (4 mg/kg) or mitomycin C (1 mg/kg) as positive controls for induction of micronuclei and chromosomal aberrations, respectively. The results showed that, compared to in control mice, AFM₁ treatment led to significantly decreased body weight gains, and caused cytotoxic/genotoxic effects as indicated by increases in frequencies of polychromatic erythrocytes, as well as those with micronucleation (PCEMN) and chromosomal aberrations, among bone marrow cells. The concurrent administration of LP with AFM₁ strongly reduced the adverse effects of AFM₁ on each parameter. Mice receiving AFM₁ + LP co-treatment displayed no significant differences in the assayed parameters as compared to the control mice. By itself, the bacteria caused no adverse effects. Based on the data, it is concluded that the test bacteria could potentially be beneficial in the detoxification of AFM₁-contaminated foods and feeds for humans and animals.

• Aflatoxin M₁
• binding
• detoxification
• genotoxicity
• immunotoxicity
• Lactobacillus strains

Acknowledgments

The work was supported by the Tunisian Ministry of Higher Education and Scientific Research (Unit of Immunology, Environmental Microbiology, and Cancerology), the Higher Institute of Biotechnology of Beja (Animal Biotechnology Dept) and Unit of Histology Cytology and Genetics, Faculty of Medicine, University of Monastir, Monastir, Tunisia.