Thermoregulation after acute ethanol, during chronic exposure and during withdrawal from ethanol dependency was studied using genetically heterogeneous (HS) mice, and lines of mice selected in replicate for smaller (HOT1, HOT2) or greater (COLD1, COLD2) decline in rectal temperature (Tre ) after intraperitoneal ethanol. First, HS mice were injected with 20% ethanol in 0.9% NaCI, or NaCI alone during sessions of behavioral thermoregulation in individual temperature gradients (9-38°C). Internal temperature (Tj ) was monitored with implanted telemetry devices. An imaging system recorded selected temperature (Tsel ) within the gradient every 5 sec. Acute 2.25 and 2.60 g ethanol/kg produced significantly lower Tj than NaCI. 2.60 g/kg also produced significantly lower Tsel than 2.25 g/kg or NaCI. 2.75 g/kg and above incapacitated mice. Comparison of responses using a thermoregulatory index indicated 2.25 or 2.60 g/kg decreased the regulated temperature. Similar methodology was followed using the selected lines and 10% ethanol (2.0, 2.25, 2.65 g/kg to COLD mice; 2.65, 2.85 g/kg to HOT mice; 3.0 g/kg to HOT2 mice) or NaCI. All responded similarly to NaCl, with transient rise in Tj After an effective ethanol dose mice manifested a regulated decrease in Tj by lowering Tsel concomitant with falling Tj . In both replicate pairs COLD mice were more sensitive than HOT, indicating that a true difference in the CNS regulator of body temperature was selected for in these animals. Photoperiod effect was characterized by quantifying thermoregulatory behavior of COLD2 mice after acute 2.60 g 7.5% ethanol/kg or NaCl, at 0400 , 0800 , 1200, 1600 , 2000 and 2400 hours , using above methodology. Baseline T₁ was significantly lower during hours of light, than during darkness. Photoperiod had little effect on thermoregulatory response to ethanol, possibly because of arousal associated with experiments. Thermoregulatory tolerance to ethanol was investigated using HS mice implanted with telemetry devices and monitored in the gradient on days 1, 2, 4, 7 and 11 of 11 consecutive days of 10% ethanol (2.75 g/kg) or NaCl injections. Dispositional, rapid and chronic tolerance developed, indicating that functional tolerance is a regulated phenomenon in mice. In a separate experiment HS mice were implanted with telemetry devices and injected with ethanol for 11 consecutive days at constant temperature; dispositional but not functional tolerance developed. To characterize thermoregulation during withdrawal, HS mice were made dependent upon ethanol using a vapor chamber; T; Tsel and activity were monitored in the gradient until 26 hours post withdrawal. Withdrawing mice showed unaltered regulated temperature, but lower Tsel than controls. This suggested increased metabolic heat production. Thermoregulation during withdrawal was similarly studied using the selected mouse lines. COLD mice responded like HS mice. Withdrawing HOT1 mice were more active than controls; withdrawing HOT2 mice showed lowest Tsel of any genotype but maintained Ti above controls. These results suggest a more severe withdrawal reaction in HOT, than in COLD mice. To investigate a possible mechanism underlying ethanol hypothermia, responses of HOT and COLD mice to intracerebroventricular serotonin were characterized. Dose-dependent decreases in Tre were measured in mice equipped with indwelling brain cannulae and held at constant temperature after injection of 0.3, 0.8, 2.0, 5.0 or 11.0 μg serotonin into the lateral brain ventricle. COLD mice were significantly more sensitive than HOT mice. Subsequently HOT1 and COLD1 mice were equipped with brain cannulae and implanted telemetry devices; thermoregulatory behavior after 11.0 μg serotonin was monitored. Both genotypes lowered Tj significantly more in the gradient than did similar mice at constant ambient temperature, indicating that decline in Tj after serotonin was a regulated phenomenon. The serotonergic system was altered during selection for differential Tre response to ethanol, indicating a role for serotonin in mediating ethanol hypothermia.

African elephants are known to survive in habitats with ambient temperatures from below 0°C to about 50°C, implying that they may be exposed to great thermal challenges, especially in hot regions of Africa, where they are common. Thermoregulatory behaviour of the African forest elephant in its natural habitat and the microclimates that it utilizes have not previously been investigated. To understand how such an enormous animal behaves in the hot, humid natural forest environment, I investigated microclimates at forest-savannah interfaces (bais) in Lobeke National Park in Cameroon, observed forest elephants’ likely thermoregulatory behaviour and correlated the behaviours with environmental microclimatic variables. Portable weather stations equipped with data loggers were deployed at five study sites to record microclimatic variables for three days per site. I used the fixed point sampling method to observe and record behaviours of forest elephants, during the hot, dry season. Black globe temperature reached an average of about 33ºC during the day in the bais and decreased to a mean of about 20ºC in the night. The day globe temperature often exceeded the body temperature of the elephants, but the vapour pressure of air was lower than that on the elephant’s skin. Therefore, at 100% humidity and estimated skin temperature of 35ºC, I assume elephants of this study lost heat by evaporation, both under the forest canopy and in the open bais. Wind speed in the bais was higher than that under the forest canopy, possibly facilitating convective heat loss from the elephants, particularly at night. Ear-flapping rate of the elephants correlated linearly and positively with dry-bulb and globe temperatures. Shade-seeking and dust-bathing only showed weak positive associations both with dry-bulb globe and temperatures. Between 06:00-24:00, elephants that were observed spent a mean of 40% of their time walking, 55% foraging, 7% shade-seeking, 45% ear-flapping, 4% dust-bathing and 9% of time performing water-related activities. The higher number of elephants in the bais at night as opposed to the numbers in the bais during the day, as revealed by the findings of this study, suggests that the forest elephant may have a more favourable mode of dumping its excess body heat in the open bais than under the forest canopy at night. All the bais and their vicinity that were investigated in this study were heavily trampled with elephant spoors, because many elephants frequently congregated in the area due the presence of nutritious herbaceous plants, mineral salts and variations in microclimates in the bai-savannah interfaces. The differences in microclimates in the bais and their vicinity may play a major role in influencing the forest elephant’s thermoregulatory behaviour. To the best of my knowledge, my study suggests for the first time that the forest elephant may use microclimates at the bai interface for thermoregulatory needs. However, my study is limited because it was executed for a short duration and over the hot dry season, and factors that may affect elephants such as physiology, the availability and quality of forage and predation risk were not included in this investigation. All these factors may have affected the accuracy of my findings. For these reasons the inferences made in this study on elephant microclimate selection would need further investigation before concrete conclusions are drawn. Expensive research cost, human safety, fear of human presence and hence alteration of elephant behaviour and the obscure nature of the equatorial forest have been recurrent issues hindering the investigation of behaviour of free-living African forest elephants. I suggest that it would be worthwhile investigating the forest elephant’s behaviour further by applying GPS/satellite telemetry, real time bio-logging and camera trap techniques, which offer a practical means to carry out an extensive study in the evergreen hot humid equatorial forest of the Congo Basin.

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Commercial broiler chickens are withdrawn from feed prior to harvesting, transport and processing. This feed withdrawal period does not reduce carcass yield but is significant in reducing the potential for carcass contamination from undigested feed or fecal material that may remain in the digestive tract if feed is not withdrawn. However, withdrawing feed can result in an increase in bacterial contamination due to the decrease in physiological pH during fasting. Recently, consumers are more interested in how food animals are raised, prepared for, and processed. In response to these concerns, the feasibility of developing a “feed withdrawal” feed that could be provided to commercial broilers during the traditional feed withdrawal period was evaluated. The physiological effect of fasting during the feed withdrawal period is also not well understood. The focus of this study was to determine if feedstuffs that are readily accessible to commercial feed mills was evaluated to determine if body weight loss could be reduced and commercial broilers could be processed acceptably when allowed access to this feed during the traditional feed withdrawal period. In addition, the physiological response of commercial broilers at different ages to fasting was determined. The emphasis of this study was to determine the effect of fasting periods of commercial broilers on the hormones insulin and glucagon, circulating levels of glucose and body temperature compared to fulled birds. The results of this research suggests that a “feed withdrawal feed” that is available to commercial feed mills is feasible to allow commercial broilers access to feed during the traditional feed withdrawal period and still be processed with no contamination concerns. In addition, the impact of fasting on the hormones glucagon and insulin, circulating levels of glucose and body temperature were shown to be significantly changed during a fasting period.

<p> Body temperature regulation at high ambient temperatures was compared in pregnant and non-pregnant female albino rats. At an ambient temperature of 40°C, pregnant rats maintained lower body temperatures than non-pregnant rats without added expenditure of moisture for evaporative cooling. This was surprising because of the increased heat load on the pregnant animal resulting from a large weight gain and increased food intake. The maintenance of lower body temperatures in the heat by pregnant rats was possible because (1) pregnant rats produce less heat; i.e. consume less oxygen during exposure to 40°C than do non-pregnant rats and thus need to dissipate less heat; and (2) pregnant rats have a lower body temperature threshold for increased submaxillary salivary gland output in the heat, which makes more water for evaporative cooling available to them at lower body temperatures.</p> <p> The maintenance of lower body temperatures in the heat by pregnant rats suggests that pregnant rats have a need or a preference for lower body temperatures in the heat. The change in body temperature regulation during pregnancy is likely related to physiological and anatomical changes in the body which accompany pregnancy. Alterations in body temperature regulation to meet the changed physiological state of pregnancy provide another example of the body's remarkable ability to maintain homeostasis.</p> / Thesis / Doctor of Philosophy (PhD)

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