(A) Schema of female ApoE^–/– mice on an HFD with 150 mM SerBut or NaBut on a butyrate basis, or water ad libitum for 6 weeks. (B) Oil Red O (ORO) staining of aortic root plaque. (C) CD68⁺ IHC staining of aortic root plaque. Original magnification, ×20. (D) Representative images of immunofluorescent staining of aortic root. (E) Quantification of ORO⁺ aortic root valve area. (F) Histological Stary scoring of plaque severity, (G) quantified CD68⁺ area, and (H) necrotic core of CD68⁺ IHC staining. (I) Quantified DAPI⁺, (J) DAPI⁺ per plaque area, (K) iNOS⁺, and (L) iNOS⁺ cells per plaque area in immunofluorescence stain. (M–O) Flow cytometry of immune cells infiltrating the aorta: (M) CD45⁺ total leukocytes, (N) CD11b⁺ monocytes, and (O) CCR2⁺CD11b⁺ monocytes. (P) Water consumed by cages for the first 19 days of experiment. Data represent mean water consumed between 2 cages (replicates) as weight change of bottle converted to water volume. Error bars represent SD. (Q) Plasma IL-6 and (R) IFN-γ. (S) Blood flow cytometry of Ly6G⁺CD11b⁺ circulating neutrophils. n = 5/cage and n = 10 mice per group. Data points represent individual mice displayed with median ± SEM. Statistical analyses were performed using a 1-way ANOVA with Tukey’s, Welch’s (if SDs were significantly different by Bartlett and Brown-Forsyth tests), or Kruskal-Wallis (if data were not normally distributed determined by Shapiro-Wilk test) post hoc test. P values less than 0.10 are shown. Outliers were removed by ROUT testing at Q = 1% in I–L. Scoring in C was done blinded. Data in C and F–H represent 2 independent pooled experiments: n = 10 for water and SerBut groups and n = 10 for NaBut groups in a single experiment. “B6,NC” denotes age-matched C57BL/6 mice on normal diet as non-statistical comparison to visualize healthy examples. Scale bars: 200 μm.