Effects of dietary fibers on obesity related physiological parameters in C57BL/6 mice

Abstract Text:  Obesity, a metabolic disease resulting from an imbalance between caloric intake and expenditure, is a global concern. Studies suggest that the intake of dietary fiber improves metabolic health; however the amount of dietary fiber and the fiber type that contribute to this improvement is unclear. This completely randomized study investigated the effect of 1.25, 2.5, and 5.0% (w/w) glucomannan or oat beta-glucan in the diet versus a control diet on metabolism. Obesity related variables such as liver steatosis, and short chain fatty acid (SCFA) production was evaluated in diet-induced obese male C57BL/6 mice. Six weeks old mice (n=84) were fed one of 7 diets for 12 wks. On d 84, whole blood was collected and serum metabolites were analyzed. Small liver lobe portions were used to examine steatosis severity and cecum samples were analyzed for SCFA concentration. The glucomannan diets had an interaction between fiber and their inclusion levels for relative liver weight (P < 0.05) and percent steatosis (P < 0.001). The oat b-glucan diet resulted in lower serum triglyceride concentrations (P < 0.05), whereas including glucomannan in the diet resulted in higher acetate and propionate levels (P< 0.05) in comparison to the other dietary treatments. In the liver, the inclusion of 2.5% and 5.0% of fiber caused a decrease in microvesicular fat in comparison to the inclusion of 1.25% of fiber. This study highlights that the inclusion of glucomannan and oat beta-glucan fiber in the diet at specific inclusion levels is capable of having significant effects on relative liver weight, percent steatosis, and serum triglycerides in obese mice. Glucomannan decreased the severity of mediovesicular fat, while both fibers decreased severity of macrovesicular fat. Thus, supplementing a diet with an adequate amount of specific dietary fiber may be a strategic method to reduce obesity in animals, and this may eventually be translated towards treating human obesity to reduce obesity related health issues.

Keywords:  Fiber, Obesity, Mice