Fig. 6

Gut microbial and metabolite characteristics of recipient mice after fecal microbiota transplantation (FMT). a At the operational taxonomic units (OTU) level, the principal component analysis (PCA) showed that gut microbiota composition of NEC microbiome recipient mice was significantly different compared to control microbiome recipient mice(p < 0.01). b No significant differences were found by PCA between the GC and GCB groups. c No significant differences were found by PCA between the GN and GNB groups. d The average relative abundances at the phyla level in each group. e Mann–Whitney U test of the upregulated or downregulated phyla in the GC and GN groups. f Relative abundance of top 20 OTUs responsible for discriminating NEC microbiome-recipient mice and control microbiome-recipient mice in GN, GC, GNB and GCB groups. g Level of butyrate in mice from GC and GN groups. GN, NEC patient fecal microbiota transplantation (FMT) plus NEC model; GC, control patient FMT plus NEC model; GNB, butyrate-treated with NEC patient FMT and NEC model; GCB, butyrate-treated with control patient FMT and NEC model; HCF, mixed fecal samples from control patients for FMT; HNF, mixed fecal samples from NEC patients for FMT. *p < 0.05