Impact of probiotic Limosilactobacillus reuteri DSM 17938 on amino acid metabolism in the healthy newborn mouse

We studied the effect of feeding a single probiotic Limosilactobacillus reuteri DSM 17938 (LR 17938) on the luminal and plasma levels of amino acids and their derivatives in the suckling newborn mouse, using gas chromatography and high-performance liquid chromatography. We found that LR 17938 increased the relative abundance of many amino acids and their derivatives in stool, while it simultaneously significantly reduced the plasma levels of three amino acids (serine, citrulline, and taurine). Many peptides and dipeptides were increased in stool and plasma, notably gamma-glutamyl derivatives of amino acids, following ingestion of the LR 17938. Gamma-glutamyl transformation of amino acids facilitates their absorption. LR 17938 significantly upregulated N-acetylated amino acids, the levels of which could be useful biomarkers in plasma and warrant further investigation. Specific fecal microbiota were associated with higher levels of fecal amino acids and their derivatives. Changes in luminal and circulating levels of amino acid derivatives, polyamines, and tryptophan metabolites may be mechanistically related to probiotic efficacy.

Automated summary

This study examined the impact of feeding a single probiotic on the levels of amino acids and their derivatives in the intestines and plasma of suckling newborn mice. The results showed that the probiotic increased the abundance of amino acids and their derivatives in the stool, while simultaneously reducing the plasma levels of certain amino acids. Additionally, the ingestion of the probiotic led to an increase in peptides and dipeptides, particularly gamma-glutamyl derivatives of amino acids, in both the stool and plasma. Specific gut microbiota were also found to be associated with higher levels of fecal amino acids and their derivatives.