Diurnal transcriptome analysis of liver samples collected every 4 hours over 24 hours from SPF and GF WT and LKO male mice (n = 3/time point/group) maintained in 12:12 LD (ZT2, -6, -10, -14, -18, and -22). (A) WT-median-normalized expression of differentially expressed (DE) genes within identified KEGG pathways. (B–E) VST-normalized expression of leading-edge genes in FA metabolism (B), PPAR signaling (C), and GNG (D and E) D between SPF and GF WT and LKO mice, with the exception of Pck1 and Pck2 (E), which are only differentially expressed in the SPF group (SPF and GF groups shown separately). Data represent mean ± SEM.