Electronic Theses and Dissertations

Identifier

2676

Date

2016

Document Type

Thesis

Degree Name

Master of Science

Major

Health and Sport Science

Concentration

Nutrition Science

Committee Chair

Marie van der Merwe

Committee Member

Randal K Buddington

Committee Member

Helen Sable

Abstract

Reproduction, an energetically costly process, is subject to nutritional and metabolic control. There is a high occurrence of female infertility in obese women, and Polycystic Ovarian Syndrome (PCOS), a condition characterized by androgen excess and oligo- and amenorrhea, is highly associated with obesity and diabetes mellitus. Obesity is characterized by chronic, low-grade inflammation and increased circulating pro-inflammatory cytokines. These pro-inflammatory molecules can alter insulin signaling, thereby contributing to glucose intolerance and insulin resistance, both hallmarks of type 2 diabetes. This study seeks to elucidate the relationship between obesity, inflammation, and reproductive dysfunction through diet intervention. Diets rich in n-3 poly-unsaturated fatty acids (PUFAs), such as found in fish oil, are considered to have anti-inflammatory effects. We induced obesity and reproductive dysfunction in C57BL/6 female mice by feeding a “Western-type” high fat diet (45% energy from fat) with lard as the source of fat. At 16 weeks of age, the experimental group was switched to a diet of identical composition but with fish oil as a source of fat for an additional 8 weeks. Changes in reproductive function and estrous cycle regularity were assessed by vaginal cytology. Metabolic outcomes were evaluated by measuring body weight, food consumption, glucose tolerance, fasting insulin levels, and adipose and liver histology. Inflammatory status was determined by circulating cytokine and adipokine levels. Reproductive irregularity was successfully established by 16 weeks of age at which time the mice also had increased glucose intolerance and higher circulating leptin levels. At 24 weeks, mice that had remained on the lard based diet weighed more, had a dramatic increase in fat deposition in the liver, showed worse glucose tolerance response, and had higher fasting insulin levels than their fish-oil counterparts. Consumption of the fish oil diet for 8 weeks did not restore estrous cycle regularity for all C57BL/6 female mice, however, cyclicity did improve for fish oil mice that exhibited reduced weight gain. These findings suggest including fish oil in the diet of obese females will improve metabolic status and improve estrous cycle regularity for those whose weight is responsive to the treatment.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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