Dietary Fat and Cholesterol Interactively Alter Serum Lipids and Gut Microbiota in Wistar Rats

Effects of dietary fat type on serum lipids and gut microbiota in cholesterol-fed rats were investigated. Forty-eight male Wistar rats were assigned (8/group) into three cholesterol-free (control) diets containing Corn Oil (CO), Sheep Tallow (ST) or Olive Oil (OO) or three cholesterol-supplemented (experimental) diets (COC, STC, OOC) and given ad libtium for nine weeks. Serum lipids, atherogenic indexes and several biological parameters were determined. Total Bacterial Counts (TBC) and seven bacterial groups were assessed. High-density lipoprotein cholesterol was higher (p<0.003) in CO (89.9 ± 6.5 mg/dl) and OO (80.9 ± 3.0 mg/dl) than ST (55.9 ± 4.3 mg/dl). Higher (p<0.05) total cholesterol and atherogenic coefficient were respectively found in OOC (131.4 ± 9.9 mg/dl, 1.20 ± 0.03 mg/dl) and COC (113.6 ± 10.6 mg/dl, 1.46 ± 0.35 mg/dl) than OO (96.4 ± 2.6 mg/dl, 0.19 ± 0.03 mg/dl) and CO (93.6 ± 2.6 mg/dl, 0.04 ± 0.03 mg/dl), but not in STC (95.8 ± 6.5 mg/dl, 0.70 ± 0.20 mg/dl) versus ST (87.0 ± 7.8 mg/dl, 0.60 ± 0.06 mg/dl). Neither fat nor cholesterol affected body weight, food intake, Bacteroidetes, Clostridium cluster IV, Lactobacillus, and Prevotella. Total Bacterial Count, Clostridium Coccoides-Eubacterium rectalae and Bacteroides were respectively higher (p<0.001) in ST (74.0 ± 20.0, 53.1 ± 8.5, 103.6 ± 32.3) than OO (24.8 ± 3.1, 18.9 ± 5.8, 32.3 ± 15.5). Bacteroides was higher (p<0.05) in ST (103.6 ± 32.3) than COC (38.7 ± 7.8), and STC (97.2 ± 13.5) than OO (32.3 ± 15.5) or COC (38.7 ± 7.8). Firmicutes and Clostridium Coccoides-Eubacterium rectalae were respectively lower (p<0.05) in STC (15.3 ± 1.2, 19.0 ± 4.3) and COC (19.0 ± 2.8, 14.4 ± 1.5) than ST (30.3 ± 4.7, 53.3 ± 8.5) and CO (32.7 ± 2.8, 33.0 ± 7.8), but not in OOC (23.5 ± 3.7, 34.4 ± 6.0) versus OO (25.3 ± 4.7, 18.9 ± 5.8).In conclusion, dietary fat and cholesterol alter serum lipids and gut microbiota in an interaction that is likely to have clinical connotations in cholesterol-related disorders.