Figure 3.

Impact of human milk fortifier type on the gut microbiome, gut inflammation, and oxidative stress in VLBW infants over time

(A and B) Longitudinal trajectories of (A) Shannon index and (B) inverse Simpson index, indicating alpha (within-sample) diversity over time in infants receiving BHMF (n = 14) or H2MF (n = 16); p values are from trend comparison using splinectomeR (999 permutations).

(C) PCoA depicts beta (between-sample) diversity based on Bray-Curtis dissimilarity (Jaccard distances in Figure S4A) at each time point; p values are from PERMANOVA (99,999 permutations). See Table S1A for betadisper test results (permutation test for homogeneity of multivariate dispersions).

(D) Genera with >10% prevalence across all samples that differed in prevalence or relative abundance (centered log-ratio [CLR] transformed) between groups over time are shown here (complete data are shown in Tables S1B–S1D, and regression analysis is shown in Figure S5). For Erwinia, the distance between groups at T1 indicates a random difference at baseline.

(E) Gut inflammation (fecal calprotectin) and oxidative stress (urinary F2-isoprostane). The p values are from Wilcoxon sum rank test (for boxplots) or using splinectomeR (for longitudinal trajectories, 999 permutations) or Fisher’s exact test (for prevalences) (^∼p < 0.10, ∗p < 0.05, ∗∗p < 0.01). T1, study day 0 (before fortification); T2, study day 7 (during fortification); T3, week 33 AGA (end of fortification); and T4, week 35 AGA (follow-up after fortification). AGA, adjusted gestational age; BHMF, bovine-derived human milk fortifier; H2MF, human-derived human milk fortifier; PCoA, principal coordinate analysis; VLBW, very low birth weight.