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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.
1

The role of material stereotypic behaviour on developmental outcomes in piglets / O papel do comportamento estereotipado materno no desenvolvimento de leitões

Tatemoto, Patricia 23 November 2018 (has links)
Stereotypic behaviour is considered an indicator of compromised welfare. We have conducted studies to test the controversial hypothesis that stereotypic behaviour helps animals to cope with challenges. We proposed that animals that do not express stereotypies could be under more compromised welfare, than the ones showing the behaviour, when exposed to difficult situations. Rather than asking to the animal if stereotypies are indicating good welfare, we assessed the effects on foetal programming. This study investigated the outcomes of stereotypies measured in sows (Sus scrofa) during gestation in shaping their offsprings phenotype measuring both behavioural and physiological indicators of welfare. Environmental enrichment is an efficient protocol, acting in the causal factors of stereotypies, such as motivational systems, to reduce repetitive, invariant behavioural patterns, defined as stereotypies. We demonstrated that stereotypies in pregnant sows are related with a reduction in fear indicators in their offspring. Then, we showed that environmental enrichment, in the last third of gestation, improved the welfare of sows and also the welfare in their offspring. Comparing the brain of the offspring of sows kept in enriched and non-enriched environments and comparing non-enriched sows performing stereotypies with non-enriched sows not showing stereotypies, we identified eight genes related with neuroplasticity and psychiatric diseases, which were differentially methylated. The main contribution of this study is that maternal stereotypic behaviour during gestation decreases fear indicators and alters the neuroepigenome of the limbic system of the offspring. As far as we know, this is the first evidence showing that stereotypies expressed by the mother during gestation did affect offsprings emotionality, in which the mechanism were epigenetic changes in the brain. / O comportamento estereotipado é considerado um indicador de comprometimento do bemestar. Nós conduzimos estudos para testar a controversa hipótese de que o comportamento estereotipado ajuda os animais a lidar com desafios. Propusemos que animais que não expressam estereotipias possam estar sob um bem-estar mais comprometido do que aqueles que demonstram o comportamento, quando expostos a situações difíceis. Ao invés de perguntar ao animal se as estereotipias estão indicando um bem-estar adequado, avaliamos os efeitos na programação do feto. Este estudo investigou os resultados de estereotipias em fêmeas suínas (Sus scrofa) durante a gestação no fenótipo da prole, acessando indicadores comportamentais e fisiológicos. O enriquecimento ambiental é um protocolo eficiente, atuando nos fatores causais de estereotipias, como os sistemas motivacionais, para reduzir padrões comportamentais repetitivos e invariantes, definidos como estereotipias. Nós demonstramos que estereotipias em suínas prenhes estão relacionadas com uma redução nos indicadores de medo na prole. Em seguida, mostramos que o enriquecimento ambiental, no último terço da gestação, melhorou o bem-estar das porcas e também o bem-estar de seus filhos. Comparando o cérebro da prole de porcas mantidas em ambientes enriquecidos e não enriquecidos e comparando porcas não enriquecidas realizando estereotipias com porcas não enriquecidas sem estereotipias, foram identificados oito genes relacionados com a neuroplasticidade e doenças psiquiátricas, que foram diferencialmente metilados. A principal contribuição deste estudo é que o comportamento estereotipado materno durante a gestação diminui os indicadores de medo e altera o neuroepigenoma do sistema límbico da prole. Até onde sabemos, esta é a primeira evidência mostrando que estereotipias expressas pela mãe durante a gestação afetaram a emocionalidade da prole, na qual o mecanismo era uma mudança epigenética no cérebro.
2

Effectiveness of cannabidiol in reducing ketamine-induced schizophrenia-like behaviour in both male and female rats

Collins, Michelle Amber January 2011 (has links)
Schizophrenia is a debilitating and costly mental illness. Many patients do not respond well to currently available treatments, and adverse side effects are common. Cannabidiol (CBD), a natural component of the Cannabis Sativa plant, has been shown to have a number of therapeutic qualities, including potential as a new antipsychotic. Although CBD has been used in several different models of schizophrenia, previous research has failed to consider possible sex differences in responsiveness to the compound. The present research therefore used both male and female rats in the widely used ketamine model of schizophrenia. PVG/C Hooded rats were randomly assigned to one of four experimental conditions: a saline only control group (saline injection followed by second saline injection; N = 6M, 6F); ketamine only group (ketamine injection followed by saline injection; N = 6M, 6F); cannabidiol low dose group (ketamine injection followed by a cannabidiol injection of 10mg/kg; N = 6M, 6F); and a cannabidiol high dose group (ketamine injection followed by a cannabidiol injection of 20mg/kg; N = 6M, 6F). Behavioural testing occurred in a Y-maze and open-field, where both normal and stereotyped behaviours were recorded, as well as locomotor activity and spatial memory. Ketamine successfully induced stereotypy but failed to induce hyperlocomotion. Findings support the potential antipsychotic effects of CBD, particularly for reducing stereotypic behaviour in females. Results found data trends that suggest sex differences in responsiveness to CBD when administered with ketamine, although further research is needed due to lack of statistical significance.

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