DIFFERENCES IN NUTRITIONAL OUTCOME MEASURES BETWEEN PREADOLESCENTS AND ADOLECENTS WITH ANOREXIA NERVOSA WHO RECEIVED A NASOGASTRIC FEEDING TUBE VERSUS ORAL DIET UPON HOSPITAL ADMISSION by Paige E. Herring Background: Anorexia nervosa (AN) is a disease defined by an extreme weight loss due to an intense fear of gaining weight, and it is the third most chronic disease in adolescent females. Hospitalizations are common among patients with AN due to the major consequences that can arise from this disease. Most of the complications can be resolved with significant weight gain, so hospitals have an implemented feeding protocols to optimize weight gain. Studies have shown that nasogastric (NG) feedings have resulted in a greater weight gain and reduced length of stay without significant side effects. Objective: The purpose of this study is to examine the association between demographic and clinical characteristics and mode of nutrition therapy (oral feeding vs. NG tube feedings) in a population of pre-adolescents and adolescents with a hospital admission diagnosis of AN. The clinical outcome measures are length of stay (LOS), weight gain, and suspected refeeding syndrome. Participants/Setting: The study sample includes 64 patients between the ages 9 and 20 years who have been admitted to Children’s Healthcare of Atlanta between January 1, 2014 and December 31, 2015 for clinical treatment of AN. The demographic, anthropometric, mode of nutrition therapy and clinical characteristics of the patient population were obtained. Statistical Analysis: Frequency statistics were used to describe demographic, anthropometric, mode of nutrition therapy and clinical characteristics of the patient population. A Student’s t-test was used to examine differences in continuous variables by tube feeding status, while a Mann-Whitney U test was used for the non-normally distributed variables. A Chi-square test was used to examine differences in tube feeding status by categorical variables. Results: Data were collected and analyzed for 64 patients, with a mean age of 14.6 + 2.4 years, and the majority of the population being female (93.8%) and Caucasian (92.2%). Approximately half (n=30, 47%) of the population received an NG tube during the admission. Mean discharge BMI was significantly higher in those who received an oral diet vs. NG tube (16.67 vs. 17.08, respectively; p=0.042) while weight change was significantly lower (1.3 kg vs. 2.1 kg, respectively; p=0.012) and LOS shorter (8 days vs. 11 days, respectively; p=0.002) There were no significant differences in other characteristics by mode of nutrition therapy. Conclusion: NG tube feeding is an effective method for feeding hospitalize adolescent patients with AN to yield greater weight gain results. Future studies are necessary to determine the amount of time exclusively on the NG tube, reasons for choosing NG vs. oral feedings, and other variables associated with weight gain and length of stay.

1. Lymnaea was the subject of an established behavioural conditioning paradigm where pairings of a neutral lip tactile stimulus (CS) and a sucrose food stimulus (US) results in a conditioned feeding response to the CS alone. The current objective was to dissect trained animals and examine electrophysiological changes in the feeding circuitry which may underlie this learning. 2. Naive subjects were used to confirm that US and CS responses in vivo persisted in vitro since this is a pre-requisite for survival of a learned memory trace. This required the development of a novel semi-intact preparation facilitating CS presentation and simultaneous access to the CNS. 3. The nature and function of the CS response was investigated using naive animals. Intracellular recordings revealed that the tactile CS evokes specific, consistent synaptic responses in identified feeding neurons. Extracellular recording techniques and anatomical investigations showed that these responses occurred through a direct pathway linking the lips to the feeding circuitry. A buccal neuron was characterized which showed lip tactile responses and supplied synaptic inputs to feeding neurons indicating that it was a second-order mechanosensory neuron involved in the CS pathway. 4. Animals trained using the behavioural conditioning paradigm were tested for conditioned responses and subsequently dissected~ Intracellular recording from specific identified feeding motoneurons revealed that CS presentation resulted in significant activation of the feeding network compared to control subjects. This activation was combined both with an increase in the amplitude of a specific synaptic input and an elevation in the extracellular spike activity recorded from a feeding-related connective. A neuronal mechanism to account for these findings is presented. 5. The role of motoneurons in the feeding circuit was reassessed. It is demonstrated, contrary to the current model, that muscular motoneurons have an important contribution during feeding rhythms through previously unreported electrotonic CPG connections.

published_or_final_version / Zoology / Doctoral / Doctor of Philosophy

The lipid composition of swine is characteristic of the species and is also a reflection of their dietary history. Other investigators have established that the physical properties and composition of swine depot fat may be altered by variation of the dietary lipid. Dietary regimens employing vegetable oil-bearing materials and their effect on meat quality has received the attention of animal nutritionists for a considerable period. Less is known about the nutritive value of the more highly unsaturated lipids, such as fish oils, and their effect on the lipid composition of swine tissues. Even less is known about the fate of oxidized fish oil lipids in swine rations. This research had for its purpose the investigation of the fate in swine of the dietary marine lipid, menhaden oil, and its effect on composition of depot lipids. The state of autoxidation of the oil and the effect of certain antioxidants on the fatty acid composition of swine was determined. Growth studies on swine were made using menhaden oil of various oxidation states as the dietary lipid. The effect of antioxidants, ∝-tocopherol acetate and ethoxyquin, was also investigated. At the conclusion of the diet trials, tissue samples, representing the five dietary regimens, were removed for analysis. The fatty tissues examined were outer back fat, inner back fat, and kidney fat. Samples of liver tissue for lipid analysis were also taken. The lipids from the respective tissues were extracted and interesterified with methanol to yield the methyl esters of the fatty acids. Hydrogenation of the unsaturated methyl esters for chain length confirmation was carried out. Qualitative and quantitative gas-liquid chromatographic analysis of the unhydrogenated and hydrogenated methyl esters of the fatty acids were performed on diethylene glycol succinate column. The results of these investigations showed that a particular dietary fatty acid can be selectively deposited in animal tissues. Long chain polyunsaturated fatty acids of menhaden oil, such as 20:5, 22:5, 22:6 were sparsely deposited in adipose tissues. The depot fat composition showed a mixture of characteristic menhaden oil fatty acids with the typical fat synthesized by swine. Fatty acid composition of tissue from swine fed oxidized menhaden oil with and without antioxidants showed very similar fatty acid composition as those fed fresh menhaden oil. The results of this investigation supported the beneficial effect of vitamin E (∝-tocopherol acetate) and ethoxyquin as in vivo antioxidants. / Graduation date: 1964

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I consider two types of foraging situations. In the first type, the forager knows the location and quality of no more than one food item or habitat at a time. I call this myopic foraging. In the second situation, the forager may know the location and quality of more than one food item or habitat at a time. I call this periscopic foraging. I develop theoretically both models and the predictions generated by each. Myopic models predict that foragers should have a so-called "bang-bang" control with respect to the choice of food types. Periscopic models predict that foragers will have a continuous control with respect to the choice of food types. I experimentally tested for the presence of each type of control in a field study that employed hummingbirds feeding on artificial resources. As predicted by the theory, the transition of behavior from picky to opportunistic was significantly sharper for the myopic than for the periscopic foragers. Furthermore, theory predicts that there should be some range of relative values of the rich and poor food types over which the myopic foragers are opportunistic, while the periscopic foragers exhibit a partial preference. This prediction was supported by the data. I predicted that the partial preferences of periscopic foragers would result from the hummingbirds exploiting those poor quality feeders which were located nearest to the best foraging path among rich feeders. The data supported this prediction. Periscopic foragers also performed as predicted by becoming more selective on rich feeders as the densities of both rich and poor feeders increased. I developed a model of optimal sampling behavior that hypothesized birds have evolved in an environment of exploitative competition. The model predicted a rule of departure from a resource patch that depended on the presence or absence of nectar in a sampled as well as the expected quality of the nectar. Hummingbirds performed according to the model's predictions.

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