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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Produção e qualidade do leite e da carne de caprinos anglo nubianos suplementados com óleos vegetais /

Chávari, Andréia Cristina Toniolo, 1980. January 2015 (has links)
Orientador: Heraldo Cesar Gonçalves / Coorientador: Roberto de Oliveira Roça / Banca: Otavio Rodrigues Machado Neto / Banca: Claudete Regina Alcalde / Banca: Renata Branco Arnandes / Banca: Paulo Roberto de Lima Meirelles / Banca: Otávio R. Machado Neto / Resumo: O uso de lipídeos em dietas de animais ruminantes de alta produção tem sido uma estratégia para aumentar a densidade energética da dieta e manipular o perfil de ácidos graxos do leite e da carne, porém podem alterar os padrões de fermentação ruminal e, por isso, promover prejuízo à produção. Assim, o objetivo deste trabalho foi avaliar o consumo e os parâmetros ruminais de cabras suplementadas com óleos vegetais na alimentação. Foram utilizadas quatro cabras da raça Saanen canuladas no rúmen e foram avaliados quatro tratamentos: dieta controle e com inclusão de 30 g de óleos de canola, girassol ou soja/kg de matéria seca da dieta. O experimento foi conduzido no delineamento em quadrado latino 4x4, com períodos de 10 dias cada. O consumo de forragem foi estimado por óxido de cromo como marcador externo, e o de suplemento, por diferença entre o alimento fornecido e as sobras diárias. Os parâmetros de fermentação ruminal (pH, concentração de ácidos graxos de cadeia curta e nitrogênio amoniacal) foram avaliados de amostras de líquido ruminal colhidas a cada duas horas, durante 12 horas no último dia de cada período. Não foi verificado efeito da suplementação lipídica sobre o consumo de matéria seca, e, dentre os nutrientes, o consumo de extrato etéreo foi maior para todos os tratamentos com óleo e a fibra em detergente ácido (FDA) foi maior no tratamento com óleo de canola. O valor de pH foi maior para o tratamento com óleo de soja e apresentou efeito quadrático para tempo de coleta. A concentração total de ácidos graxos de cadeia curta (AGCCtotal) e do ácido acético apresentaram efeito quadrático para tempo de coleta. As concentrações dos ácidos propiônico e butírico bem com a razão acético/propiônico (A/P) apresentaram efeito cúbico para tempo de coleta. A inclusão de 30 g de óleos de canola, girassol ou soja/kg de matéria seca da dieta po / Abstract: The main focus of animal food products market has been toward products with lower fat content and fatty acid profile that characterizes them as functional foods. Therefore, this study aimed to evaluate the inclusion of three sources of vegetable oil in lactating goats diet on production in 120 days of lactation, and the effect of these sources and lactation stage on fortnightly composition and fatty acid profile of goat milk at 20, 50, 80 and 110 days of lactation. It was adopted a completely randomized design and there were used 32 Anglo Nubian goats distributed in four treatments: control diet and diets with inclusion of 30 g/kg of dry matter of diet of canola, sunflower or soybean oil. The dairy production was 182,75 kg and there was no difference for treatments. Among the constituents only urea nitrogen was influenced by treatment and presented lower content for control treatment. Lactose content reduced 0,0107g/ day of lactation. Defatted dry extract and somatic cell count had quadratic effect with minimum values around 100 and 33 days of lactation, respectively. The content of urea nitrogen, also with a quadratic effect, was higher at 93 days of lactation. For protein, there was interaction among treatments and period and, at the end of lactation, its content was increased. The inclusion of vegetable oils promoted reduction in total saturated fatty acids (SFA) and increased the total content of monounsaturated fatty acids (MUFA) and conjugated linoleic acid (CLA). The proportions MUFA/SFA, PUFA/SFA and the atherogenicity and thrombogenicity indexes (AI, TI) and the relation HH (hypocholesterolemic fatty acids/ hypercholesterolemic fatty acids) improved with oil addition in animal diets. The addition of vegetable oil in diets for lactating goats improve the fatty acid profile with no impairment on milk production and composition and the milk from early stages of lactation has better nutritional quality / Doutor
32

The effect of glucose on the food intake of goldthioglucose injected mice.

Lahti, Janet 13 January 1972 (has links)
Jean Mayer has postulated the presence of glucoreceptors located primarily in the ventromedial hypothalamic nuclei of the brain which are activated by glucose in the measure that they utilize it. According to Mayer, hunger occurs when glucose is not available for metabolic purposes and satiation supervenes when glucose is made available. Control of this mechanism rests with the glucoreceptors. These receptors are believed to be destroyed when an injection of the compound goldthioglucose is given to mice. These animals subsequently become obese and are found to have gold deposits and lesions in the ventromedial area and also in other parts of the brain. If the glucoreceptors are destroyed and cannot respond to the presence of glucose in the blood, it would be predicted that food intake would not change with the glucose level. The purpose of this investigation was to see if the food intake of goldthioglucose injected animals is affected by a glucose injection. One hundred and twenty mice were divided into four groups. One group, the controls, received no goldthioglucose. The other three groups received the following dosages: .5 mg. of goldthioglucose per gram of body weight, 1.0 mg. of goldthioglucose per gram of body weight and 1.3 mg. of goldthioglucose per gram of body weight. Fifty seven days after the goldthioglucose injection a training period began in which the mice were taught to consume their entire daily food intake during a 50 minute period. Then the experimental period began during which the animals were maintained on the 23 hour and 10 minute deprivation schedule. During this period the mice were given intraperitoneal injections of 60 mg. of glucose or normal saline on alternate days for ten days. The amount of food consumed in the 50 minutes beginning 15 minutes after the glucose or saline injection was determined. Food intake of the goldthioglucose injected animals was not different than that of the controls under any factor of the experiment. The results do not support Mayer's idea that the glucoreceptors as he describes them are destroyed by goldthioglucose.
33

Home range and resource use of sable antelope in the Okavango Delta

Hensman, Michael C. 15 January 2013 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Masters in Science Centre for African Ecology, School of Plant Animal and Environmental Sciences, 2011. / Habitat selection occurs across a range of different spatial scales and is influenced by a variety of factors, ultimately determining how animals distribute themselves across the landscape. Studying the decisions that an individual animal makes across different levels of selection, from its choice in dietary item to predator avoidance strategies, is a fundamental link in understanding the response of groups of animals and ultimately entire populations that may provide insight into population performance. The study formed part of a broader study focused on the decline of rare antelope species. Specifically this study was aimed at establishing the home range and resource use of sable antelope in a region where they were initially expected to be thriving. The levels of selection covered in this study are: the location of home ranges of an individual or social group within the landscape; the use of various habitat components within the home range; and the procurement of food items within those habitats. At the highest level, the broad objectives were (1) to determine where sable occupied home ranges within the landscape, indicating the suitability of various landscape units to sustain sable populations and (2) to determine the relative use of habitat types within those home ranges that may enable sable to avoid predation and acquire resources required to survive and reproduce. At the lowest level of selection the characteristics of forage selection and how the grass quality in the different vegetation types during different seasons affects the success of sable herds was explored. The broad objectives were (1) to determine the effect of seasonal flooding and rainfall on grass greenness in the floodplains and upland vegetation types and the consequent use of those vegetation types by sable antelope and (2) to determine how exploitation of resources in the floodplains and in the uplands contributed to the nutritional status of sable. I additionally quantified the time spent browsing and determined the composition of the browse component of the diet of sable. Adult female sable from each of three adjacent sable herds were fitted with GPS collars providing hourly GPS co-ordinates. Adaptive LoCoH was used to determine home range location and annual, seasonal and core home range extents. A vegetation map was created and the number of GPS locations within each vegetation type was counted to determine their relative use in relation to availability within the home ranges. GPS collars were used to locate herds daily so that foraging observations of browsing and characteristics of the grasses grazed could be attained. Acceptability and dietary contributions of grass species and browse were determined for each sable herd during different seasons. The availability of grass species on the floodplain grasslands and in the upland grasslands and woodlands was estimated. Water and the availability of key resources posed a constraint on where sable home ranges were established. Sable simply did not occupy the region in the north of the study area further than 7 km from permanent water and floodplain grasslands. Herds generally avoided open savanna, mopane woodlands and Kalahari apple-leaf woodlands characterised by sparse grass cover, particularly during the dry season. Home ranges were relatively small compared 4 to the range estimates from herds in Kruger National Park. There was no obvious seasonal difference in home range extent nor were there large areas of overlap between home ranges of adjacent herds. Observations during the study indicated that competitor species, including zebra and wildebeest, concentrated on the floodplain grasslands. Throughout the year H. dissoluta was the most strongly favoured grass species and contributed most to the diet of the sable herds in both the wet and dry season. During the dry season sable herds expanded their diet to include Aristida stipitata and Aristida meridionalis which are generally considered poor forage value species for cattle but that retained some greenness. Additionally, the contribution of browse, especially the leaves of Croton megalobotrys, Philenoptera nelsii and Combretum mossambicense and the flowers of Kigelia africana, constituted an important bridging resource during the extended dry season. Crude faecal protein levels remained above the suggested maintenance levels throughout the annual cycle. Crude faecal protein levels were elevated prior to calving when sable spent more time foraging on the floodplain grasslands where high value forage species such as Paspalum scrobiculatum, Panicum repens and Urochloa mossambicense and sedges were eaten. Indications are that the constraint posed by the distribution of water within the landscape, rather than resource limitations within occupied home ranges, are the primary limitation to population performance in the Kwedi concession. / Wilderness Safari, the Wilderness Wildlife Trust, the Conservation Foundation, Classic Africa and National Research Foundation (NRF) of South Africa.
34

Fire-grazer interactions in a Highveld grassland in South Africa

Skhosana, Felix Vusumuzi January 2017 (has links)
A dissertation submitted to the Faculty of Science in fulfilment of the requirements for the Master of Science degree. in School of Animal, Plant and Environmental Sciences, University of The Witwatersrand, Johannesburg July 2017. / Fire is known to affect spatial patterns of grazing by altering the amount and quality of forage. Animals select the post-burn green flush that remains palatable until the grass recovers its biomass. How quickly the grass regrows depends on the rainfall and grass growth rates, and also grazing intensity. Theoretically, highly concentrated grazing can maintain short (relatively more palatable) grasslands throughout a growing season. Therefore this study aimed at; i) determining how long different grazer species were attracted to the burn, and whether this increased grazing pressure (as a result of concentrating grazers on a small burnt patch) maintained a short, palatable grass sward throughout the growing season, ii) investigating the long-term impacts of herbivore attraction to small burns on grass community and landscape function in a Highveld grassland. We therefore monitored grazer utilization of an experimentally applied small (5ha) burnt patch using dung counts and camera traps, and also measured the structural changes of the burnt patch over a period of 12 months. To test whether this process of attraction to small burns could have long-term impacts on grass community composition and landscape function we quantified species composition, infiltration rates, soil compaction, soil moisture, and ANPP in another landscape which had received 10+ years of small annual burns (a firebreak). A novel finding was that indeed grazers especially the short-grass specialist stayed on the burn and kept the grass short (<10cm) for the duration of the study post fire: the burn only treatment on the 5ha burn recovered its biomass within 2 months of the first rains. This result was due to the fact that it was a drought year with half the normal rainfall (and lower grass regrowth rates). However, the long-term study indicated that the attractive effect of small fires in this ecosystem alters both community composition and ecosystem properties. The firebreak had more bare ground and less water infiltration than the surrounding grassland – but was more diverse and had higher grass productivity. It also continued to attract the short-grass specialist species (blesbok, wildebeest and hartebeest). This counter-intuitive result indicates that perhaps these grasslands are not as severely degraded as we think. This study therefore, showed that coupling small burns with appropriate grazer species has a great potential for creating palatable grazing “hotspots”, in sourveld grassland without obvious damage to ecosystem function. / LG2018
35

Calcium Imaging of Hypothalamic Pro-opiomelanocortin Neurons During Ingestive Behaviors in Mice

Li, Xueting January 2024 (has links)
Hypothalamic pro-opiomelanocortin (POMC) neurons are canonically recognized as key anorexigenic neurons in the melanocortin circuit with a role in satiety and energy homeostasis. However, optogenetic stimulation does not decrease feeding behavior during ad-lib fed animals in a physiologically relevant manner. This suggests that there are possible nuances in their activity dynamics such as timing (when a neuron is active in relation to a specific behavior), direction (inhibition or excitation), or specificity (if only certain subgroups of POMC neurons are active). POMC neurons in the hypothalamus are a molecularly diverse population, which suggests that they would display diverse neuronal activity responses during various ingestive behaviors. Currently, single-cell recordings of hypothalamic POMC neurons has never been investigated in behaving animals. Using one-photon microendoscopic calcium imaging, we characterized the neuronal activity dynamics of individual hypothalamic neurons during a broad range of feeding behaviors prior to, during, and after ingestion, during different metabolic states in mice. We show that hypothalamic POMC neurons are highly engaged during food-seeking, consumption of different nutrients, and post-ingestive responses related to circulating molecules relaying metabolic information. Individual hypothalamic POMC neurons show diverging responses in terms of valence, duration, magnitude, and timing to different feeding behaviors that are responsive to intercurrent metabolic status. Our results suggest that hypothalamic POMC neurons may integrate moment-to-moment metabolic status with feeding and food-seeking actions at short- and long-term scales to implement behaviors and autonomic responses to coordinate complex components of energy homeostasis.
36

The feeding behaviour of a sit-and-wait predator : ethological studies on Ranatra dispar (Heteroptera: Nepidae), the water stick insect / by Paul Charles Edward Bailey

Bailey, Paul Charles Edward January 1984 (has links)
Bibliography: leaves 231-[262] / xiii, 231, [112] leaves, 10 leaves of plates : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Entomology, 1984
37

Psitacídeos do cerrado = sua alimentação, comunicação sonora e aspectos bióticos e abióticos de sua distribuição potencial / Cerrado's psittacidae : feeding, sound communication, and biotic and abiotic aspects of their potential distribution

Araújo, Carlos Barros de, 1975- 19 August 2018 (has links)
Orientadores: Luiz Octavio Marcondes Machado, Gabriel Corrêa Costa / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-19T15:46:19Z (GMT). No. of bitstreams: 1 Araujo_CarlosBarrosde_D.pdf: 15759383 bytes, checksum: 3888b2cb944f52bf1ab91fa7eb9cebb4 (MD5) Previous issue date: 2011 / Resumo: O bioma Cerrado é um hotspot de conservação que se encontra em grande risco devido à agricultura ou pastagens. Levando-se em conta que alguns grupos têm maior risco de extinção, e este parece ser o caso dos Psittacidae, e ainda que por muito tempo não havia informações disponíveis sobre essas espécies, a situação era crítica. Isso, no entanto, vem lentamente mudando, e graças ao trabalho de algumas universidades brasileiras já existem informações disponíveis sobre o grupo. Neste trabalho usamos dados adquiridos em campo no Cerrado Central (DF e GO), e também dados presentes na literatura para investigar a alimentação, distribuição de potencial e também a comunicação sonora do grupo. Examinamos a existência de padrões de alimentação entre estas espécies, e também se a dieta pode ser um bom preditor da sua distribuição. Investigamos também a comunicação sonora quanto a presença de chamados específicos para a espécie, dado o grande número de espécies presentes no Cerrado. Também investigamos o alcance de comunicação destas espécies, bem como o impacto que o ruído humano pode ter nesse alcance / Abstract: The Cerrado biome is a conservation hotspot that is currently at great risk, due to agriculture or pasture. On the other hand, some groups have more risk of extinction. That seems to be the case of Psittacidae, as they are one of the most threatened bird groups of the world. For a long time there were no information available on these species, so that the situation was critical. This is slowly changing, and thanks to the work of some Brazilian universities there are now some information available on the group. In this work we use new data acquired at the Central Cerrado, and also data present in literature, to further investigate the feeding, potential distribution and also the sound communication of the group. We examine the existence of feeding patterns among these species, and also if diet may be a good predictor of the species distributions. We also investigate the sound communication. We examine the presence of specific calls for the species, the range of communication of these species, and also the impact that human noise may have in their sound communication / Doutorado / Ecologia / Doutor em Ecologia
38

An in vivo electrochemical analysis of the role of dopamine in feeding behaviors

Holmes, Lorinda Jean January 1990 (has links)
The involvement of dopamine in anticipatory and consummatory aspects of feeding behaviors was investigated in the present thesis. All measurements of dopaminergic activity were taken by in vivo electrochemical techniques. In Experiment 1, dopamine efflux in the nucleus accumbens and caudate of male rats was monitored during sessions in which a small, unsignalled liquid meal was consumed. Increases in the electrochemical measure of dopamine activity, which were of similar temporal pattern and magnitude, were observed in both the nucleus accumbens and striatum following meal consumption. These data suggest a possible postingestional role of dopamine in these two brain structures. In Experiment 2, a conditioned feeding paradigm was utilized to study the role of dopamine during a discrete anticipatory phase of feeding. Rats were conditioned to discriminate between a positive conditioned stimulus (CS+) predictive of meal delivery, and a negative conditioned stimulus (CS-) that was not associated with food. Increases in dopamine activity, as determined by changes in electrochemical oxidation currents, were found to be greater during the CS+ than during the CS- in both the nucleus accumbens and caudate. In addition, the magnitude of increase was greater in the nucleus accumbens than the caudate, suggesting that the accumbens may be preferentially involved in the processing of external incentive stimuli. The results support a role for dopamine in both the nucleus accumbens and caudate during appetitive or anticipatory responding for food in the male rat. / Medicine, Faculty of / Graduate
39

Resources overlap and the distribution of grazer assemblages at Telperion and Ezemvelo nature reserves

Deliberato, Henrique Guindalini January 2017 (has links)
A research report submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2017. / The distribution of grazing herbivores is influenced by several factors, including spatial and temporal availability of resources. The Telperion and Ezemvelo Nature Reserves (TENR), located on the border between Gauteng and Mpumalanga Provinces, experienced a declining hartebeest (Alcelaphus buselaphus caama) distribution over the last years. Simultaneously, an increase in the density of plains zebra (Equus quagga) occurred in the reserves. In this study, I investigated the changes in the distribution of four herbivore species, namely red hartebeest, plains zebra, blue wildebeest and black wildebeest in TENR, and the possible influence that biotic and abiotic factors had on the distribution of hartebeest between 2010 and 2016. Data of aerial surveys conducted in the wet season of each year were used to assess the variation in herbivores distribution along the period. Furthermore, the influence of variables known to affect herbivore distribution (e.g. distance to water, slope gradient, spatial distribution of other herbivore species and vegetation greenness) was tested on hartebeest distribution in TENR. The results indicate that blue wildebeest (Connochaetes taurinus) had the highest distribution variation, while plains zebra presented the most spread distribution among the four species, and black wildebeest (Connochaetes gnou) concentrated their distribution almost entirely at the Ezemvelo nature reserve. Hartebeest avoided areas with the highest concentration of plains zebra, but did not show the same avoidance for areas with prevalence of wildebeest species. Further, high quality forage resources influenced the hartebeest distribution in TENR. Thus, competition for forage resources with bulk feeders may have affected the population and distribution of hartebeest between 2010-2016. / LG2018
40

Terminação de bovinos de corte em pastagem de capim Aruana sobressemeado com aveia e azevém associados à leguminosa e/ou adubação nitrogenada / Beef steers finishing on pasture of Aruana grass overseeded with oats and ryegrass associated with legume and/or nitrogen fertilization

Schmitz, Gean Rodrigo 17 February 2017 (has links)
CAPES / O trabalho foi conduzido para avaliar a terminação de bovinos de corte em pastagem de Capim Aruana sobressemeado com aveia e azevém associados à leguminosa e/ou adubação nitrogenada. O delineamento foi inteiramente casualizado, com três tratamentos e três repetições. Foram testados três sistemas forrageiros no período de inverno,tendo como base a pastagem de Aruana (Panicum maximum, cv.Aruana) sobressemeado com aveia e azevém: ‘Nitrogênio’ (N) –200 kg de N ha-1; Amendoim forrageiro e 100 kg de N ha-1; Ervilhaca e 100 kg de N ha-1. A adubação foi dividida em cinco aplicações, o período experimental foi de 127 dias. Foi utilizado o sistema de lotação continua, com carga animal variável, a oferta de forragem preconizada de 9,0 kg/100 kg de peso vivo. A pastagem foi manejada utilizando-se de 24 animais castrados de 21 meses, com peso vivo médio inicial de 425 kg, destes 18 foram teste e seis reguladores. As avaliações da forragem e do desempenho animal foram realizadas a cada 21 dias. A avaliação do comportamento animal foi realizada duas vezes por período, durante 24 horas em cada avaliação. O maior nível de adubação nitrogenada proporcionou diferenças na estrutura da pastagem, porém a produção diária de forragem foi semelhante entre os tratamentos. O tempo de pastejo na consorciação com ervilhaca foi superior ao amendoim forrageiro e semelhante aos demais na adubação com 200 kg de N ha-1, no entanto, o ganho médio diário foi semelhante para os tratamentos. O tempo de 20 bocados e o número de passos por minuto foram superiores na maior adubação nitrogenada quando comparado a consorciação com amendoim,e semelhante à estes na consorciação com ervilhaca. Embora o consórcio com amendoim associado a 100 kg de N ha-1 tenha causado redução no tempo de pastejo e apresentado maior tempo de ruminação, não ocorreram diferenças no desempenho produtivo e nas características de carcaça dos animais em terminação. / The objective was to evaluate finishing of beef steers in Aruana pasture overseeded with oats and ryegrass and mixed with legume with or no nitrogen fertilization. The design was completely randomized, with three treatments and three replications. Three forage systems have been tested tested in winter, based on Aruana fodder (Panicum maximum, cv. Aruana) mixed with oats and ryegrass: 'Nitrogen' (N) -200 kg of N ha-1; Forage peanut and 100 kg of N ha-1; Vetch and 100 kg of N ha-1. The fertilization was shared in five applications, for 127 days. The continuous stocking system was used, with variable stocking rate, and forage on offer of 9,0 kg/100 kg of live weight. The grazing was managed with 24 castrated animals of 21 months,425 kg of initial avarage live weight. Being 18 testers and six regulators. Evaluations of forage and animal performance were made every 21 days. For animal behavior, the evaluations were done twice in each period, for 24 hours. The highest level of nitrogen fertilization showed differences in pasture structure, however, the forage daily production was similar between the treatments. The grazing time on mixture with vetch was superior for Forage peanut and similar to the others when fertilization was 200 kg of N ha-1, although, the average daily gain was similar for both treatments. The time of 20 bites and the number of steps per minute were higher for higher nitrogen fertilization, when compared to the peanut intercropping, and similar to those when mixed with vetch. Although the peanut consortium associated with 100 kg of N ha-1 caused a reduction in grazing time and presented a longer rumination time, there were no differences in the productive performance and carcass characteristics of the finished animals.

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