(P16-036-23) Effects of Replacing Cellulose With Physiologically Relevant Doses of Soluble Fiber on Weight Gain, Bodycomposition, Glucose Metabolism, and Cecal SCFAs in C57Bl6j Mice

Objectives: Objectives Fiber intakes close to recommended levels (14g/1000 kcal, Institute of Medicine (IOM)) are associated with less chronic disease. In semi-purified rodent diets, the fiber source is cellulose. Our objective was to determine if substituting soluble fiber for cellulose would affect metabolism of mice fed a 45% kcal from fat diet.

Methods: A mix of oat hull fiber, pectin and beta-glucan was added to a high fat rodent diet at the typical US intake or at the recommended level (8g/1000kcal (low), 14g/1000kcal (high)). Five groups of C57Bl/6 mice (n=12) were fed the experimental diets for 16 weeks. The third diet was also high fat (DIO), but only contained cellulose. The fourth diet was a low fat semipurfied diet, and the fifth was chow. Body composition was measured by MRI. OGTT and ITT were conducted at weeks 14 and 15. Cecal short chain fatty acids were measured by GC-FID.

Results: Mice fed the DIO diets gained more weight than mice fed the chow and low-fat diets (P<0.05). Mice fed the DIO diets had a higher body fat percentage than mice fed the chow and low-fat diets. When the cellulose was replaced with soluble fiber, the mice had a higher body fat percentage (P<0.05). Mice fed the low-fat diets had lower fasting glucose levels then mice fed the DIO diets, and the soluble fiber did not have an effect. Mice fed the low-fat diets had significantly lower AUC in OGTT than mice< fed the high fat diets, and the soluble fiber did not have an effect. There were no diet effects in insulin tolerance at week 16. While the soluble fiber did not improve metabolism in the mice fed the DIO diets, there were dose-dependent increases in cecal acetic, propionic and butyric acids, and decreases in isobutyric and isovaleric acids.

Conclusions: Rodent models are used extensively to investigate the role of nutrients in maintaining metabolic health and the prevention of chronic disease. These current results indicate that exogenous, primarily soluble fiber added to a high fat, semi-purified rodent diet does not improve body composition or glucose metabolism in mice, despite significant increases in the cecal production of SCFA.

Funding Sources: Utah State University