Thesis Defense Announcement

The School of Health Studies announces the Final Thesis of

Sunita Sharma

for the Degree of Master of Science

March 29, 2018 at 9:30 AM in Elma Neal Roane Field House

Advisor: Marie Vander Merwe

The effect of dietary interventions on intestinal-associated metabolites and immune parameters

ABSTRACT:The obesity epidemic has driven the search for dietary interventions for weight reduction. In the current study we determined the role of dietary composition and also timing of feeding on weight loss, with a specific focus on changes in intestinal parameters. 7-week-old C57BL/6 male mice (n=57) were fed a 45% high fat diet for 6 weeks to induce weight gain. Mice were then divided into 6 groups (n=9 per group) and followed the following dietary protocols: 1) ad libitum HF feeding (HF), 2) ad libitum feeding of lower fat diets, including chow (Chow) and a vegan based diet (DF) and 3) a high fat diet feeding restricted by either calories (CR), or time (ADF, TRF). Animals weight and food consumption were monitored and animals were euthanized for tissue harvest after 8 weeks on respective diets. Body composition were determined before and after intervention. All dietary interventions resulted in weight loss. Ad libitum consumption of the HF diet resulted in fat and lean mass gain, while both low fat diets resulted in fat loss, while gaining lean mass. Restricted HF feeding caused both fat and lean mass loss, with TRF being the most beneficial. The small intestinal length and cecum weight was increased in all low fat diets, with no difference in colon length between groups. Colonic lymphocytes were phenotyped and quantified. While there was no difference in population composition, there was an increase in absolute number of lymphocytes, with a statistical significance increase in Foxp3+ Tregs in the vegan based diet compared to the dietary protocols of extended fasting and high fat diet. The results from this study demonstrate that reduction in calorie intake irrespective of diet composition will result in weight loss. The low fat diet had the most beneficial effect on body composition. The dietary protocol did not alter splenic or colonic immune composition, but the vegan based diet did result in increased lymphocytes, specifically Foxp3 Tregs.