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- Genre: Masters Thesis
Description
Background: Despite research aimed at understanding the mechanisms of metabolic syndrome (MetS), this prevalence continues to rise. Recent literature indicates that dietary fiber may offer prevention and management of MetS in various studies involving human and animal subjects. Objective: This six-week study aimed to test the efficacy of a novel fiber-rich complex in young male Sprague-Dawley rats by examining the effects on high-fat diet-induced weight gain, adiposity, high blood sugar, lipid imbalance, and oxidative stress.
Methods: 24 six-week-old male Sprague Dawley rats were randomly assigned into three diet groups (regular chow, high-fat, or high-fat + fiber) and fed for six weeks. Blood from the animals was collected at weeks 0, 3, and 6 for fasting blood glucose (FBG) analysis and at weeks 0 and 6 for lipid profile assessment. Body mass was weighed weekly. Organ mass, nasoanal, and tail length were measured at week 6. Findings were considered significant at p-value < 0.05. Data collected at week 6 were analyzed by one-way ANOVA, whereas data collected at multiple time points were analyzed by two-way ANOVA with diet and time as factors. Student-Newman-Keuls posthoc analyses were used to compare differences between and within groups.
Results: No significant differences were found in the size of rats fed each diet as measured by tail length (p = 0.599) or nasoanal length (p = 0.875). Abdominal circumference was not significantly different (p = 0.477). There were no significant differences between groups in fasting whole blood HDL cholesterol (p = 0.297), fasting whole blood HDL triglycerides (p = 0.624), plasma total triglycerides (p = 0.137), or beta-hydroxybutyrate (p=0.185) after six weeks of each dietary treatment. Similarly, plasma true triglycerides and free glycerol were not significantly different between groups (p = 0.148 and 0.529, respectively). Thiobarbituric acid reactive substances (TBARS) were also not significantly different between groups (p = 0.412).
Conclusion: The addition of the novel fiber-rich complex did not significantly affect high-fat diet-induced weight gain, adiposity, high blood sugar, lipid imbalance, or oxidative stress in this experimental design.
ContributorsLing, Jingyu (Author) / Sweazea, Karen (Thesis advisor) / Sears, Dorothy (Committee member) / Kim, Min-Hyun (Committee member) / Arizona State University (Publisher)
Created2024
Description
First year college students have been identified as a vulnerable population for weight gain and the onset of overweight and obesity. Research regarding the gut microbiome has identified differences in the microbial composition of overweight and obese individuals compared to normal weight individuals. Dietary components like dietary fibers, act as prebiotics, or fermentable substrate, that the gut microbiota use for metabolic functions including the production of short-chain fatty acids. The objective of this longitudinal, observational study was to assess changes in the gut microbiota over time in relation to changes in fiber consumption in healthy college students at a large a southwestern university (n=137). Anthropometric and fecal samples were collected at the beginning and end of the fall and spring semesters between August 2015 and May 2016. Both alpha, within sample, diversity and beta, between sample, diversity of participant gut microbes were assessed longitudinally using non-parametric pairwise (pre-post) comparisons and linear mixed effect (LME) models which also adjusted for covariates and accounted for time as a random effect. Alpha and beta diversity were also explored using LME first difference metrics and LME first distance metrics, respectively, to understand rates of change over time in microbial richness/phylogeny and community structure. Pre-post comparisons of Shannon Diversity and Faith’s PD were not significantly different within participant groups of fiber change (Shannon diversity, p=0.96 and Faith’s PD, p=0.66). Beta diversity pairwise comparisons also did not differ by fiber consumption groups (Unweighted UniFrac p=0.182 and Bray Curtis p=0.657). Similarly, none of the LME models suggested significant associations between dietary fiber consumption and metrics of alpha and beta diversity. Overall, data from this study indicates that small changes in fiber consumption among a free-living population did not have an impact on gut microbial richness, phylogeny or community structure. This may have been due to the low intake (~15 g/d) of fiber. Further study is needed to fully elucidate the role that fiber plays in the diversity and composition of the gut microbiota, especially when delivered from a variety of food sources rather than fiber supplements.
ContributorsLolley, Sarah (Author) / Whisner, Corrie (Thesis advisor) / Sears, Dorothy (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2020