Document Type

Thesis

Date of Degree Completion

Fall 2014

Degree Name

Master of Science (MS)

Department

Biology

Committee Chair

Holly Pinkart

Second Committee Member

Gabrielle Stryker

Third Committee Member

James Johnson

Abstract

Obesity has become an ever increasing global problem. This has caused people to turn to sugar substitutes, no calorie sweeteners, to reduce their caloric intake. However, recent studies have shown that it is not just caloric intake that can affect weight, but also the diversity of the bacteria in the gut (Turnbaugh et al., 2009). It has been shown that an increased Firmicutes:Bacteroidetes ratio and an overall decrease in microbial diversity leads to an obesity associated gut microbiome (Turnbaugh et al., 2009; Ley et al., 2005). The purpose of this study was to determine if two of the most popular sugar substitutes on the market, sucralose and aspartame, when ingested at levels below the US Food and Drug Administration's acceptable daily intake, would cause an increase in the Firmicutes:Bacteroidetes ratio or alter the overall diversity of the gut microbiota of mice. Sucralose and aspartame treatment was given orally by adding the sugar substitutes to the drinking water of BALB/c inbred mice for a period of 7 weeks. Bacterial phyla ratios were determined by using fluorescent in situ hybridization whereas species diversity was determined by denaturing gradient gel electrophoresis. After 3 weeks of treatment, both the sucralose and aspartame treated groups showed a significant increase in their Firmicutes:Bacteroidetes ratio until weeks 6 and 5 respectively at which time they decreased back to near base line levels. A downward trend in overall diversity and species richness was also shown for both treatment groups.

Comments

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