Trypanosoma brucei is the vector of African trypanosomiasis in both domestic animals (nagana) and sleeping sickness in humans (Human African Trypanosomiasis). These protozoan parasites are transmitted by the bite of infected tsetse flies (Glossina sp.). African trypanosome infections cause parasite-induced anorexia (PIA) and cachexia in livestock, experimental animals and in humans, and are of economic, veterinary and medical importance in sub-Saharan Africa. The overall aim of this project was to characterise the phenomenon of inappetence in relation to overall energy budget in African trypanosome infection and to then identify potential causal factors and mechanisms. A mouse model of T.b. brucei infection was established with a reproducible time course for the development of inappetence and bodyweight loss. Following an initial parasitaemic peak on day 6 post-infection, a profound period of inappetence was observed from days 7 to 11, accompanied by a 10% loss of body mass. Metabolisable energy intake was reduced, while assimilation efficiency increased significantly but not enough to compensate for the severe reduction in food intake. During the course of T.b. brucei infection, both total energy expenditure and physical activity were reduced. Although physical activity was markedly declined in both light and dark phases, trypanosome infected mice maintained their circadian rhythm albeit at a lower amplitude, with most of the activity occurring at the start of the dark phase. Resting metabolic rate was unchanged in infection. Plasma concentrations of the inflammatory cytokines, IL-6 and TNF-α were increased in infected mice and were associated with inappetence. Reductions of leptin and insulin concentration corresponded to a loss in fat mass. The hypothalamic control of appetite appeared to be normal with increases in appetite stimulating AgRP, decreases in the appetite inhibiting POMC and MC4R. There has been no previous data published on the control of appetite and energy expenditure in African trypanosome infections thus the data presented here provides a novel insight into the pathophysiology of this serious disease, and may lead to new therapies to manage the clinical and veterinary consequences of trypanosome infection.

The annual energy budget was determined for the rainbow trout and kokanee populations of a small (13.3 ha) British Columbia lake. Population size of the rainbow trout aged 1⁺ and older was 4000 based on a 55 catch-day Schnabel estimate. Number of kokanee present in the lake (9000) was based on the ratio of occurrence of kokanee to rainbow trout (2.25:1) in catch. Monthly instantaneous growth and mortality rates were applied to each age group. Seasonal change in gonad weight as a percentage of body weight was similar in both species (ovaries 0.5%-13%, testes 0.5%-4%). Sex ratios were generally even in kokanee but there was a higher percentage of females (57.7%) in the rainbow trout. The relationship between egg number per female (F) and fork length (L) was calculated (rainbow trout, F = 18.7 L•⁹⁵⁹; kokanee, , F = 2.84 L¹•⁴¹⁴). The percent volume of each major food item was determined by stomach analysis. In only one month (May) was the food item of highest % volume the same in both species. Seasonal change in energy content of the food was estimated. Calculation of daily ration (as a percentage of body weight) was based on turnover rates (y) of food consumed at different temperatures (y = .545 e•º⁹¹x, where x is in °C). Feeding experiments using natural foods indicated assimilation efficiencies of 85.5%. Continuous (20 hr) measurement of routine metabolism of individual fish was made with a respirometer situated in Marion Lake, between, August 1967 and October 1968. Rate of oxygen uptake (Q) in ml/hr, at 15 °C was plotted against weight (W) in kg (Q = 62.6 W•⁷⁶). To determine the amount of energy trapped within the two populations, sample fish were dried (gonads separately) and burned in a calorimeter. The percent moisture of the fish was 74-78% during the year with marked increases at spawning time (rainbow 82%, kokanee 88%). The seasonal changes in energy content of immature fish were small (rainbow trout 6050-6200 cal/ash-free g; kokanee 6150-6300 cal/ash-free g). However mature fish underwent sharp reductions in energy content prior to spawning (rainbow trout 6100 to 5500 cal/ash-free g; kokanee 6100 to 5^00 cal/ash-free g). The pattern of seasonal change in energy content of the gonads was similar to that of the body. Average biomass present in the lake was 1.53 x 10⁴ Kcal/ha (12.3 kg/ha) for the rainbow trout, and 2.23 x 10⁴ Kcal/ha (16.6 kg/ha) for the kokanee. Annual production for the two populations was 2.81 x 10⁴ Kcal/ha. The ratio of production to biomass for rainbow trout was 0.80, and for kokanee was 0.71. / Science, Faculty of / Zoology, Department of / Graduate

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Bibliography: leaves 363-421. This thesis presents studies relating to the regulation of appetite, body fat stores and energy balance in the marsupial Sminthopsis crassicaudata. All of the studies presented have been published in international journals, accepted for publication, or submitted for publication. These studies have provided novel data on the regulation of food intake, body fat stores and energy balance in the marsupail Sminthopsis crassicaudata, representing fundamental advances in marsupial biology.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 113 p. : ill. (some col.), col. map. Vita. Includes abstract. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 96-101). Also available on the World Wide Web.

Thesis (M. Sc.)--College of William and Mary. / Vita. Includes bibliographical references.