Influence of oral administration of Akkermansia muciniphila on the tissue distribution and gut microbiota composition of acute and chronic cadmium exposure mice.

Cadmium (Cd) contamination is a serious food safety problem. Acute and chronic Cd exposure changes the gut microbiota composition and damages the gut barrier function. Akkermansia muciniphila (AKK), a promising candidate for the next-generation probiotics, has been reported to protect the mucus layer in the colon and significantly decrease the effects of Cd exposure in mice. Thus, the mice model was adopted to investigate the influence of oral administration of AKK on the toxic distribution and changes of gut microbiota composition caused by acute and chronic Cd exposure. In both acute and chronic Cd exposure experiments, 40 mice were divided into four groups (normal group, AKK group, Cd group and Cd plus AKK group). The Cd contents in feces and tissues were measured by a flame or graphite furnace atomic absorption spectrophotometer and gut microbiota composition was determined through 16S rRNA gene sequencing. The results showed that the gavage of AKK could not reduce the accumulation of Cd in the liver and kidney. The oral administration of AKK showed a certain influence on the gut microbiota composition of acute Cd exposure mice and limited influence on that of chronic Cd exposure mice. These results indicate the failure of AKK, as a potential protective probiotic, to reduce Cd toxicity. However, the gavage of AKK did have an influence on the gut microbiota composition of normal mice, especially on some genera in the Clostridiales order. Besides, when considering AKK's probiotic potential and its effects on host health and disease, we should take into consideration its influence on the gut microbiota composition and micro-environment.