Table 2.

The Shannon index of each group at the phylum and genus levels, M (P₂₅~P₇₅).

Shannon index	Anti-free*	Control	NEC acute	NEC recovery	H-value	P
Phylum level	0.67 (0.36~0.84)	0.47 (0.35~0.72)	0.51 (0.20~0.62)	0.32 (0.08~0.62)	3.94	0.27
Genus level	0.85 (0.61~1.20)	0.93 (0.64~1.09)	0.83 (0.71~1.09)	0.68 (0.23~1.04)	3.90	0.27

^*Anti-free, antibiotic-free group.