Fig. 8

Aging-related metabolic profile in the gut microbiota was significantly reversed by the administration of arginine-enriching B. longum strains. A PLS-DA plots of fecal metabolite profiles according to the experimental group. B Numbers of metabolite features and metabolites with defined names, and trends in different concentrations between pairwise comparisons (FDR-adjusted P < 0.05 and VIP > 1). C Detected changes in metabolites related to arginine metabolism between pairwise comparisons. VIP values (before slash) and FDR-adjusted P values (after slash) are shown and highlighted in purple for all the identified differentially presented metabolites related to arginine metabolism between pairwise comparisons (FDR-adjusted P < 0.05 and VIP > 1). The cells marked by “n.s.” indicate that alterations of specific metabolites in specific comparisons did not reach significant level (FDR-adjusted P > 0.05 or VIP < 1). O series/Y series respectively denote treatments with individual positive strains/negative strains. Three positive strains are O1(278), O2 (RG4-1), and O3 (FJSWXJ10M2); three negative strains are Y1 (FGSZY16M3), Y2 (FHaNCM25GMM1), and Y3 (FSDLZ59M1). Arg, Arginine group