Identifier

etd-04122014-224820

Degree

Doctor of Philosophy (PhD)

Department

Human Ecology

Document Type

Dissertation

Abstract

Three studies were performed to determine the effects of RS on body weight and adiposity in HF DIO, diabetic C57BL/6J and GLP-1 receptor KO mice as well as genetically obese ZDF rats. The first study was a dose-response experiment for HM260 (0, 15, or 28 g/100 g diet) against the anti-diabetes drug SG (Januvia®) (0 or 0.4 g/100 g diet) in HF DIO C57BL/6J (n=55) mice injected with STZ in order to assess synergy. The most effective combination was used in the second study, the purpose of which was to determine the mechanistic importance of GLP-1 in GLP-1R KO (n=25) in aforementioned synergy. HM260 and SG interact synergistically in HF diet to reduce adiposity at the 28% HM260 level, and SG appears to promote increased active GLP-1 when combined with 28% HM260. Combination treatment resulted in increased energy expenditure and attenuated weight gain in mice, and these activities are dependent on a functioning GLP-1 receptor. GLP-1 receptor may help regulate serum GLP-1 concentration by facilitating clearance. For the third study, the fermentation response of ZDF rats was characterized using four diets differing in starch source/type: AC, HM260, DWGC, a novel HMWG, which contained 0, 25, 6.9, and 25% RS by weight, respectively. Empty cecum weight and short chain fatty acid concentrations were significantly increased for all fiber-containing groups compared to the non-fiber control. Animals fed the whole-grain RS had a 30% greater effect than non-whole-grain RS. However, no significant differences in body weight or percent body fat were found for any diet group. These results demonstrate a synergistic effect between whole-grain and RS, and provide evidence for greater potential health benefits with whole-grain varieties of RS. ZDF rats have a defective leptin receptor, and, thus, beneficial phenotypic changes observed in previous studies in rodents fed RS appear to require leptin signaling.

Date

2014

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Keenan, Michael

Included in

Human Ecology Commons

Share

COinS