Metagenomic and proteomic approaches in elucidating aflatoxin B detoxification mechanisms of probiotic Lactobacillus casei Shirota towards intestine.

The modulation of gut microbiota and proteome due to aflatoxin B (AFB) by probiotics remains unclear. This study investigated the alterations of gut microbiota and proteome in AFB-exposed rats treated with probiotic Lactobacillus casei Shirota (Lcs). Forty male Sprague Dawley rats were randomly divided into five groups (n = 8) comprised control, AFB, AFB+activated charcoal, AFB+Lcs, and Lcs groups. The rats were subjected to different treatments via oral gavage for four weeks. Urine and serum were collected for the measurement of AFB biomarkers and organs were harvested for histological analysis. Metagenomic sequencing was performed on fecal samples to profile gut microbiota. Besides, AFB most affected organ i.e. jejunum was subjected to proteomic analysis. The results indicated that Lcs intervention significantly reduced AFB biomarkers. H&E-stained intestine showed Lcs alleviated AFB-induced inflammation and abnormal cell growth, particularly at the jejunum. Although AFB increased potentially pathogenic bacteria and reduced beneficial bacteria abundance in feces, the microbiota composition was normalized with Lcs treatment. The gut proteome analysis of the jejunum sample showed several pathways of AFB toxicity, wherein Lcs treatment demonstrated its protective effect. It is concluded that metagenomic and proteomic approaches are useful tools to understand AFB-Lcs interaction and detoxification mechanism in the gut.