Fig. 4

Principal response curves (PRC) of faecal microbiota composition showing the change in species composition of infants receiving test formula as compared to control (a). The diagram shows the first component of the PRC on the vertical axis and time on the horizontal axis with the treatments plotted as single response curves using control as reference with zero PRC values and so its curve lays over the horizontal axis. The top 15 OTUs are plotted on the separate vertical (one-dimensional) plot based on best fit with the first component of the PRC. In bold the OTUs that were significantly increased (> 0) or decreased (< 0) in Test versus Control at week 8 or at two or more timepoints (week 8/12/26) as confirmed by the two-part statistics (FDR ≤ 0.1). Percentages (means with 95% CI) of bifidobacteria (b), and ER/CC group (c) quantified by FISH at week 0/8/12/26. The HBR reference values (age-matched to week 8) are plotted as well. P-values are based on ANCOVA comparing Test versus Control with Week 8/12/26 values as outcome, stratification factor and baseline values as covariate and treatment as fixed effect: **P ≤ 0.01; ***P ≤ 0.001. Taxa names are given at the OTU level with unique (but arbitrary) numbers as identifiers, genus level (“_g_”), family level (“_f_”): Bact bacteroidaceae, Bifi bifidobacteriaceae, Lach lachnospiraceae, Rumi ruminococcaceae, Veil veillonellaceae; and phylum level: Acti actinobacteria, Bact bacteroidetes, Firm firmicutes