1600-P: Sunflower Oil HFD Feeding in Mice Leads to Gut Dysbiosis, Mild Steatohepatitis, and Impaired Glycemic Control

Introduction & Objective: High-fat diets (HFDs) influence gut microbiota and promote obesity & metabolic dysregulation. Dietary sucrose is a co-player in modifying gut microbial ecosystem towards dysbiosis. Fish & sunflower dietary fats may be consumed with/without sucrose; however, gut bacterial changes from excessive intake of these fats, without the added effect of sucrose, remain unclear.

Methods: To address this objective, we compared effects of sucrose-free, sunflower high-fat diet (S-HFD) & fish (F)-HFD feeding (24 wks) on the gut microbiota, obesity, liver inflammation, and glycemic control in C57BL/6 mice.

Results: The 16S rRNA sequencing of fecal microbiome showed that gut bacterial communities were differentially expressed between two dietary groups. Firmicutes were highly-abundant in S-HFD (40%) compared to F-HFD (3%) mice, while Verrucomicrobia were abundant in F-HFD (26%) compared to S-HFD (˂1%) mice. Firmicutes/Bacteroidetes ratios in S-HFD & F-HFD were 1.32 & 2.45, respectively. MicrobiomeAnalyst & MIAOME analyses identified highly-abundant taxa in S-HFD mice, including Oscillospira, guilliermondii, Allobaculum, Yaniella, Ruminococcus, gnavus, Staphylococcus, Clostridium, Adlercreutzia, Aerococcaceae, Anaeroplasma, Mogibacteriaceae, Christensenellaceae, & RF39, having predicted associations with host genes of metabolic disorders/pathways linked to inflammation & glucose metabolism. Compared to F-HFD mice, the S-HFD mice showed slightly increased body weights (P = 0.06) but significant differences regarding fasting hyperglycemia, hepatic macrophage infiltration (F4/80 expression), macrovascular steatosis, lobular inflammation, & expression of genes associated with de novo lipogenesis (Acaca, Fasn, and Scd1) & monocyte chemotaxis (Ccl2).

Conclusion: Taken together, S-HFD feeding in mice leads to gut dysbiosis and the clinical manifestations of moderate liver inflammation, steatosis and impaired glycemic control.