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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.
41

Avaliação da fibra fisicamente efetiva em rações para bovinos de corte / Evaluation of physically effective fiber in diets for beef cattle

Goulart, Rodrigo Silva 16 December 2010 (has links)
Objetivou-se com este trabalho avaliar o efeito de fontes e teor de fibra no consumo voluntário, no comportamento ingestivo, na efetividade de fontes de fibra, na cinética digestiva e alguns aspectos do metabolismo ruminal de bovinos de corte. Foram utilizados seis bovinos machos castrados da raça Nelore contendo cânula no saco dorsal do rúmen, alojados em gaiolas metabólicas, em delineamento do tipo quadrado latino 6x6, contendo 19 dias de período experimental cada. Seis rações foram formuladas com diferentes teores e fontes de fibra: CN (controle negativo com 10% da fração FDN de silagem de milho); CP (controle positivo com 20% da fração FDN de silagem de milho); e quatro rações contendo 10% da fração FDN de silagem de milho e 10% da fração FDN de cada uma das seguintes fontes: bagaço in natura de cana-de-açúcar (BAG), cana-de-açúcar (CAN), casca de soja (CSOJ) e torta de algodão desengordurada (TALG). Comparado ao tratamento CP, observou-se CMS semelhante (P>0,05) entre os tratamentos CAN, CSOJ e TALG (9,20, 8,60, 8,83 e 9,52 kg.dia-1, respectivamente). Contudo, tratamento BAG promoveu depressão no CMS (6,97 kg.dia-1). Ração contendo menor teor de fibra (CN) apresentou resultado intermediário quanto ao CMS. Para estimar o fator de efetividade física (fef) ou fator de efetividade (fe) foram utilizados os métodos de bioensaio preconizado por Armentano e Pereira (1997). Além disso, foram utilizados métodos laboratoriais recomendados por Mertens (1997) e Lammers; Buckmaster; Heinrichs (1996) para estimar o fef de fontes de fibra (fef1,18 ou fef>8,0 mm, respectivamente). Ao calcular o fef das fontes de fibra utilizando métodos laboratoriais, foi possível evidenciar grande divergência entre estes e os valores calculados pelos métodos de bioensaio. Medidas de efetividade física calculadas por meio de métodos laboratoriais (fef1,18 ou fef>8,0 mm) apresentaram baixa ou nenhuma correlação (P>0,05) com tempo de ruminação, tempo de mastigação, pH ruminal e mat ruminal. Por outro lado, ao avaliar os fef calculados conforme Armentano e Pereira (1997), coeficientes de correlação adequados foram observados (P<0,05) quando relacionados com tempo de ruminação, tempo de mastigação e mat ruminal. Equações de regressão envolvendo cálculos de efetividade física utilizando métodos laboratoriais e bioensaio foram sugeridas para que se pudesse oferecer aplicabilidade em condições de campo. Os valores médios de pH ruminal foram influenciados pelo nível e fonte de fibra. A concentração total de ácidos graxos de cadeia curta (AGCC) foi significativamente alterada (P<0,05) em função dos diferentes tratamentos. Rações contendo fontes e teores de fibra não alteraram o tempo médio de digestão da MS e da fração FDN (P>0,05), como também, não provocaram alteração (P>0,05) nas frações A e U referente à MS avaliadas pelo ensaio de degradabilidade in situ. Teor e fontes de fibra alteraram (P<0,05) a taxa de passagem do pool de partículas escapáveis no rúmen retículo (ke), o TMRRp e o TMRTp. Não houve diferença (P>0,05) na taxa assintótica de líquidos (L, h-1), no tempo de trânsito da fase líquida (TTL, h), como também, no TMRRL e TMRTL entre os tratamentos avaliados (média de 0,11 h-1, 8,73, 20,6 e 29,6 horas respectivamente). / This study aimed to evaluate the effect of different sources of fiber on voluntary intake, ingestive behavior, on effectiveness fiber sources, on digestive kinetics and some aspects of the rumen metabolism in beef cattle. Six ruminally canulated Nellore steers, housed in tie-stall barns, were used in a 6 x 6 Latin square design with 19 days of experimental periods each. Each experimental period consisted of 10 days of adaptation to the experimental diet and 9 days of data collection. Six diets were formulated with different contents and sources of fiber: NC (negative control - with 10% of the NDF fraction from corn silage), PC (positive control - with 20% of the NDF fraction from corn silage) and four diets containing 10% of NDF fraction from corn silage and 10% of the NDF fraction from each the following sources: sugarcane (SC), sugarcane bagasse (SCB), soybean hulls (SH) and high oil cottonseed meal (HOCM). In comparison to the PC treatment, it was observed similar dry matter intake (DMI) (P>0.05) between the treatments SC, SH e HOCM (9.20, 8.60, 8.83 and 9.52 kg.day-1, respectively). However the SCB treatment decreased DMI (6.97 kg.day-1). The diet containing lower fiber level (NC) presented an intermediate result in relation to DMI. To estimate physical effectiveness factor (pef) or effectiveness factor (fe), bioassay methods recommended by Armentano and Pereira (1997) were used. Also, laboratory methods recommended by Mertens (1997) and Lammers; Buckmaster, Heinrichs (1996) to estimate the effectiveness factor of physical fiber sources (fef1,18 or pef>8.0mm, respectively) were used. There was a large discrepancy between physical effectiveness factor of fiber sources when calculated by laboratory or bioassay methods. Measurements of physical effectiveness calculated by laboratory methods (fef1.18 or fef>8.0mm) showed low or no correlation (P> 0.05) with rumination time, chewing time, rumen pH and ruminal mat. On the other hand, when pef was calculated according to Armentano and Pereira (1997), appropriate correlation coefficients were observed (P <0.05) between pef and rumination time, chewing time and ruminal mat. Regression equations involving calculations of physical effectiveness using laboratorial methods and bioassays have been proposed to provide applicability in field conditions. The mean ruminal pH levels were influenced by the content and source of fiber. The concentration of total short-chain fat acids (SCFA) were significantly altered (P<0.05) according to the different treatments. Diets containing different sources and contents of fiber did not change the average time of digestion from the DM and NDF fraction (P>0.05), also they did not cause changes (P>0.05) in the A and U fractions of the DM evaluated by the in situ degradability study. Content and fiber sources changed (P<0.05) the ke, the TMRRp and the TMRTp. No difference was observed (P>0.05) on asymptotic rate of fluid (L, h- 1), along the transit time of the fluid phase (TTL, h) and TMRRL and TMRTL between different treatments (average of 0.11 h-1, 8.73, 20.6 and 29.6 hours, respectively).
42

Social contagion in common marmosets (Callithrix jacchus) : implications for cognition, culture and welfare

Watson, Claire F. I. January 2011 (has links)
The social transmission of social behaviours in nonhuman primates has been understudied, experimentally, relative to instrumental, food-related behaviours. This is disproportional in relation to the comparatively high percentage of potential social traditions reported in wild primates. I report a systematic survey of the social learning literature and provide quantitative evidence of the discrepancy (Watson and Caldwell, 2009). Addressing the identified deficit in experimental work on social behaviours, I also report three empirical studies investigating the contagious nature of affective states in captive, socially housed marmosets. I carried out an observational study, to determine whether marmosets are influenced by spontaneously produced neighbour calls to perform a range of behaviours associated with similar affect. My results supported a neighbour effect for anxiety in marmosets. Consistent with previous findings for chimpanzees (Baker and Aureli, 1996; Videan et al., 2005), I also found evidence for neighbour effects for aggression and affiliation (Watson and Caldwell, 2010). Through experimental playback, I investigated contingent social contagion in the auditory and visual modalities. The playback of pre-recorded affiliative (chirp) calls was found to be associated with marmosets spending increased time in a range of affiliative behaviours. Playback of video showing conspecifics engaged in a positive affiliative behaviour (allogrooming) also appeared to cause marmosets to spend longer performing various affiliative behaviours. My results indicate that social contagion of affiliation is a multi-modal phenomenon in marmosets and also represent the first evidence that allogrooming is visually contagious in primates. Sapolsky (2006) conceptualised culture as the performance of species-typical behaviours to an unusual extent, termed ‘social culture’. Researchers have yet to directly investigate a transmission mechanism. I investigated whether a social culture of increased affiliation could be initiated in marmosets through the long-term playback, of positive calls, or of video of positive behaviour. The results were consistent with a relatively long-lasting influence of the playback of affiliative calls across several affiliative behaviours. The effect appeared to last substantially beyond the specific hours of playback, between playbacks, and after playback had ceased, potentially indicating a temporary shift in social culture. These results are preliminary but provide some support for the proposal that auditory social contagion may be a transmission mechanism for social culture. The long-term video playback of allogrooming appeared to result in a transitory shift in performance of the identical behaviour (increased allogrooming) after playbacks had ceased. In addition to theoretical implications for social cognition and social culture, my findings have potential practical application for the enhancement of welfare in captive marmosets through sensory, and non-contact social, enrichment.
43

Macrobrachium rosenbergii (de Man 1879) : the antennal gland and the role of pheromones in mating behaviour

Al-Mohsen, Ibrahim January 2009 (has links)
The freshwater prawn, Macrobrachium rosenbergii (de Man, 1879) is an important aquaculture species but one that has the disadvantage of heterogeneous individual growth (HIG) according to different morphotypes. Chemical cues, especially, pheromones, are one of the most important communication types between individual prawns, along with visual and tactile methods. Testing pheromones, whilst restricting other cues, may therefore lead to a better understanding of the influence of these communicatory compounds on the prawn reproductive process. The three principle objectives of this study were therefore: 1) To examine the effect of moult stage and morphotype on pheromone-induced sexual behaviour 2) To examine the role of pheromone / urine concentrations on sexual attraction behaviour 3) To describe the functional morphology of the antennal gland and examine its possible role in pheromone production and release. Identical bioassay tanks were designed and constructed to study the reproductive behaviour of prawns. Experiments were set up to examine responses to pheromone release by live prawns over 30 minutes and behavioural response observations were made with the aid of a Closed-Circuit Videotape System (CCVS). Results were statistically analysed using a repeated measures general linear model (GLM). Three trials were designed to test the effect of moult stage of both males and females and male morphotypes on sexual attraction behavioural responses. Twelve prawns were used for each trial and each prawn was used five times (1 no-pheromone control and 4 for experimental tests). The first trial studied the effect of female moult stages (pre-, inter and newly-moulted) on sexual attraction behaviour of blue claw (BC) male. Results of this trial showed that newly-moulted females spent significantly (p<0.05) less time approaching the BC male than the pre- and inter-moult females. The second trial studied the effect of male moult stage (pre-, inter and newly-moulted) on sexual attraction to receptive females. Results showed that the time taken by the inter-moult males was (p<0.05) less than the pre- and newly-moulted males in approaching the newly-moulted female. The third trial tested the effect of male morphotypes (small male, SM, orange claw, OC and dominant blue claw, BC) on sexual attraction behaviour towards newly-moulted females. Results showed that the BC male was significantly more attractive (p<0.05) than other morphotypes to newly-moulted females and that the OC male was the least attractive. The role of moulting stage for both male and female prawns on reproductive response behaviour was investigated. Because BC males responded significantly faster towards newly-moulted female more than to either pre-or inter-moult females, results of the first trial suggest that BC males are able to use different chemical cues to gather information about a conspecific’s gender and can differentiate female’s moult stages. Since BC males responded significantly faster towards newly-moulted females more than to either pre-or inter-moult females, this suggests that females at this particular stage released a distinct sexual pheromone or concentration of pheromone that differed from those pheromones released by both pre- and inter-moult females. In contrast, newly-moulted females prefer the inter-moult BC males which indicate that females have an ability to distinguish the moult status of BC males. Furthermore, it indicates that pheromone characteristics change with the moult status of BC males. Also, newly-moulted females are most likely to be avoiding the potential costs of mate guarding with soft shell BC males. Results obtained from the third trial suggested that a newly-moulted female can discriminate male morphotypes (SM, OC and BC) from their pheromone cues. This indicates that male morphotypes release pheromones which differ from each other in some way. Newly-moulted females responded positively to both SM and BC males with different levels of attraction with the greatest attraction to BC males to BC males suggesting that pheromone released from the BC male may carry information relating to dominance status. Urine is believed to be one of the main carriers of pheromone and is usually released from the antennal gland. Different urine concentrations (0.1, 1.0, 2.0, 3.0, 5.0 and 10µl l-1) of collected urine from BC males were used to test the sexual attraction behaviour of receptive newly-moulted females. Also, the attractant capability of fresh urine following exposure to different temperature regimes (cooled at 4ºC, frozen at -70ºC and heated at 70ºC) was tested. Since newly-moulted female M. rosenbergii were attracted to BC male urine, this indicates the existence of sex pheromone in the fresh urine. Also, it was found that the sexual response of females to fresh urine of BC males was directly proportional to urine concentration with faster responses observed with increasing urine concentrations. At the three fresh urine concentrations 0.1 µl l-1, 1.0 µl l-1 and 2.0 µl l-1, statistical analysis indicated no significant difference (p>0.05) between these three concentrations while a significant (P<0.05) response was to concentrations more than 3.0 µl l-1. This may indicate that these three concentrations were not sufficient to elicit attraction behaviour in newly-moulted females. A concentration of 3.0 µl l-1 of fresh urine is suggested to be a sufficient concentration to elicit a significant sexual attraction under laboratory conditions. Response of newly-moulted female prawns to the various temperature treatments tested declined in response to nominally increasingly degradative treatments. Also, statistical analysis showed that temperature treatment and concentration added both had a significant effect on the response of females. The greatest degradation of urine attractiveness was found with the 70ºC heat treatment. It can be concluded that the pheromone components of prawn urine are friable when exposed to high temperatures. Using light and transmission electron microscopes, ultrastructural observation of the antennal gland (AG) of M. rosenbergii suggests that it has four distinct regions, the coelomosac, the nephridial tubules, the labyrinth and the bladder. Morphological and functional descriptions of each of these regions were compared with those of other aquatic Crustacea.
44

Neurotoxicity of methylmercury : analysis of molecular mechanisms and behavioral alterations /

Daré, Elisabetta, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 6 uppsatser.
45

Gene Expression in the Brains of Two Lines of Chicken Divergently Selected for High and Low Body Weight

Ka, Sojeong, January 2009 (has links)
Diss. Uppsala : Uppsala universitet, 2009.
46

Comportamento de novilhas em pastagens de Pennisetum sp, sob diferentes alturas de resíduo pós-pastejo

LIRA, Carolina Câmara 22 July 2009 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-03-23T15:33:41Z No. of bitstreams: 1 Carolina Camara Lira.pdf: 227800 bytes, checksum: 109678bb1721fbe958b921fe590e423e (MD5) / Made available in DSpace on 2017-03-23T15:33:41Z (GMT). No. of bitstreams: 1 Carolina Camara Lira.pdf: 227800 bytes, checksum: 109678bb1721fbe958b921fe590e423e (MD5) Previous issue date: 2009-07-22 / The objective of the work was to evaluate the diurne behavior of Girolanda heifers submitted to the Pennisetum sp pastures, under different heights of residue after pastejo. The experiment was carried through in the Institute Agronômico de Pernambuco (IPA), in Itambé-PE, the period of August of 2007 the July of 2008. 18 heifers of Girolanda race had been used, with age of approximately the 20-24 months and average alive weight of 370kg. The experimental design was randomized block, with three repetitions, in arrangement of parcels perhaps subdivided, being the main parcel formed by the heights of residue after-pastejo (Lower, Middle and High). Subplot had been formed by the genotypes of Pennisetum sp. (IRI 381, Venezuela and Hexaplóide). The pasture was submitted the capacity rotacionada with cycle of pastejo of 35 days (rainy time) and 70 days (dry time), being 3 days of grazing. grazing had interaction between Periods of evaluation x Genotypes only for the total variable, where genotype IRI 381 if detached when comparative with Venezuela and the Hexaploide in the heights of 80 and 120cm, with exception of the period of November of the height of 120cm. The biggest time for this activity was for height of 120cm (80,55min) in as the day of the period of March of 2007. Activities of leisure and other activities had been superior in the periods of March and May of 2008. The time of the behavioral activities diurnas suffered great influences of the climatic variations in the periods of evaluation, as well as the structure of the grass. / O objetivo do trabalho foi avaliar o comportamento diurno de novilhas da raça Girolando em pastagens Pennisetum sp. sob diferentes alturas de resíduo pós pastejo. O experimento foi realizado no Instituto Agronômico de Pernambuco (IPA), em Itambé-PE, nos períodos de Agosto, Outubro e Novembro de 2007, Março, Maio e Julho de 2008. Foram utilizados 18 animais, com idade de aproximadamente 20 a 24 meses e peso vivo médio de 376,343,4kg. O delineamento foi blocos ao acaso, com três repetições, em arranjo de parcelas subdivididas e medidas repetidas no tempo, sendo a parcela principal as alturas de resíduo pós-pastejo (Baixa, Média e Alta); as subparcelas foram formadas pelos genótipos de Pennisetum sp. (IRI 381, Venezuela e Hexaplóide) e os dias de pastejo como a sub subparcelas. A pastagem foi submetida à lotação intermitente com ciclo de pastejo de 35 dias (época chuvosa) e 70 dias (época seca), sendo 3 dias de pastejo. Houve interação entre Períodos de avaliação x Genótipos apenas para o tempo de pastejo.O tempo de pastejo apresentou uma queda no período de março e maio de 2008 devido aos altos índices de ITU (84) e ITGU (88), o que aumentou o tempo de ócio e outras atividades. O maior tempo de ruminação foi para as novilhas no resíduo alto (80,55min) no segundo dia do período de março de 2007. O tempo das atividades comportamentais diurnas sofreu grande influência das variações climáticas nos períodos de avaliação, bem como da estrutura do pasto.
47

Avaliação da fibra fisicamente efetiva em rações para bovinos de corte / Evaluation of physically effective fiber in diets for beef cattle

Rodrigo Silva Goulart 16 December 2010 (has links)
Objetivou-se com este trabalho avaliar o efeito de fontes e teor de fibra no consumo voluntário, no comportamento ingestivo, na efetividade de fontes de fibra, na cinética digestiva e alguns aspectos do metabolismo ruminal de bovinos de corte. Foram utilizados seis bovinos machos castrados da raça Nelore contendo cânula no saco dorsal do rúmen, alojados em gaiolas metabólicas, em delineamento do tipo quadrado latino 6x6, contendo 19 dias de período experimental cada. Seis rações foram formuladas com diferentes teores e fontes de fibra: CN (controle negativo com 10% da fração FDN de silagem de milho); CP (controle positivo com 20% da fração FDN de silagem de milho); e quatro rações contendo 10% da fração FDN de silagem de milho e 10% da fração FDN de cada uma das seguintes fontes: bagaço in natura de cana-de-açúcar (BAG), cana-de-açúcar (CAN), casca de soja (CSOJ) e torta de algodão desengordurada (TALG). Comparado ao tratamento CP, observou-se CMS semelhante (P>0,05) entre os tratamentos CAN, CSOJ e TALG (9,20, 8,60, 8,83 e 9,52 kg.dia-1, respectivamente). Contudo, tratamento BAG promoveu depressão no CMS (6,97 kg.dia-1). Ração contendo menor teor de fibra (CN) apresentou resultado intermediário quanto ao CMS. Para estimar o fator de efetividade física (fef) ou fator de efetividade (fe) foram utilizados os métodos de bioensaio preconizado por Armentano e Pereira (1997). Além disso, foram utilizados métodos laboratoriais recomendados por Mertens (1997) e Lammers; Buckmaster; Heinrichs (1996) para estimar o fef de fontes de fibra (fef1,18 ou fef>8,0 mm, respectivamente). Ao calcular o fef das fontes de fibra utilizando métodos laboratoriais, foi possível evidenciar grande divergência entre estes e os valores calculados pelos métodos de bioensaio. Medidas de efetividade física calculadas por meio de métodos laboratoriais (fef1,18 ou fef>8,0 mm) apresentaram baixa ou nenhuma correlação (P>0,05) com tempo de ruminação, tempo de mastigação, pH ruminal e mat ruminal. Por outro lado, ao avaliar os fef calculados conforme Armentano e Pereira (1997), coeficientes de correlação adequados foram observados (P<0,05) quando relacionados com tempo de ruminação, tempo de mastigação e mat ruminal. Equações de regressão envolvendo cálculos de efetividade física utilizando métodos laboratoriais e bioensaio foram sugeridas para que se pudesse oferecer aplicabilidade em condições de campo. Os valores médios de pH ruminal foram influenciados pelo nível e fonte de fibra. A concentração total de ácidos graxos de cadeia curta (AGCC) foi significativamente alterada (P<0,05) em função dos diferentes tratamentos. Rações contendo fontes e teores de fibra não alteraram o tempo médio de digestão da MS e da fração FDN (P>0,05), como também, não provocaram alteração (P>0,05) nas frações A e U referente à MS avaliadas pelo ensaio de degradabilidade in situ. Teor e fontes de fibra alteraram (P<0,05) a taxa de passagem do pool de partículas escapáveis no rúmen retículo (ke), o TMRRp e o TMRTp. Não houve diferença (P>0,05) na taxa assintótica de líquidos (L, h-1), no tempo de trânsito da fase líquida (TTL, h), como também, no TMRRL e TMRTL entre os tratamentos avaliados (média de 0,11 h-1, 8,73, 20,6 e 29,6 horas respectivamente). / This study aimed to evaluate the effect of different sources of fiber on voluntary intake, ingestive behavior, on effectiveness fiber sources, on digestive kinetics and some aspects of the rumen metabolism in beef cattle. Six ruminally canulated Nellore steers, housed in tie-stall barns, were used in a 6 x 6 Latin square design with 19 days of experimental periods each. Each experimental period consisted of 10 days of adaptation to the experimental diet and 9 days of data collection. Six diets were formulated with different contents and sources of fiber: NC (negative control - with 10% of the NDF fraction from corn silage), PC (positive control - with 20% of the NDF fraction from corn silage) and four diets containing 10% of NDF fraction from corn silage and 10% of the NDF fraction from each the following sources: sugarcane (SC), sugarcane bagasse (SCB), soybean hulls (SH) and high oil cottonseed meal (HOCM). In comparison to the PC treatment, it was observed similar dry matter intake (DMI) (P>0.05) between the treatments SC, SH e HOCM (9.20, 8.60, 8.83 and 9.52 kg.day-1, respectively). However the SCB treatment decreased DMI (6.97 kg.day-1). The diet containing lower fiber level (NC) presented an intermediate result in relation to DMI. To estimate physical effectiveness factor (pef) or effectiveness factor (fe), bioassay methods recommended by Armentano and Pereira (1997) were used. Also, laboratory methods recommended by Mertens (1997) and Lammers; Buckmaster, Heinrichs (1996) to estimate the effectiveness factor of physical fiber sources (fef1,18 or pef>8.0mm, respectively) were used. There was a large discrepancy between physical effectiveness factor of fiber sources when calculated by laboratory or bioassay methods. Measurements of physical effectiveness calculated by laboratory methods (fef1.18 or fef>8.0mm) showed low or no correlation (P> 0.05) with rumination time, chewing time, rumen pH and ruminal mat. On the other hand, when pef was calculated according to Armentano and Pereira (1997), appropriate correlation coefficients were observed (P <0.05) between pef and rumination time, chewing time and ruminal mat. Regression equations involving calculations of physical effectiveness using laboratorial methods and bioassays have been proposed to provide applicability in field conditions. The mean ruminal pH levels were influenced by the content and source of fiber. The concentration of total short-chain fat acids (SCFA) were significantly altered (P<0.05) according to the different treatments. Diets containing different sources and contents of fiber did not change the average time of digestion from the DM and NDF fraction (P>0.05), also they did not cause changes (P>0.05) in the A and U fractions of the DM evaluated by the in situ degradability study. Content and fiber sources changed (P<0.05) the ke, the TMRRp and the TMRTp. No difference was observed (P>0.05) on asymptotic rate of fluid (L, h- 1), along the transit time of the fluid phase (TTL, h) and TMRRL and TMRTL between different treatments (average of 0.11 h-1, 8.73, 20.6 and 29.6 hours, respectively).
48

Effects of clozapine and alprazolam on cognitive deficits and anxiety-like behaviors in a ketamine-induced rat model of schizophrenia /

Phillips, Jennifer M. January 2005 (has links)
Thesis (Ph. D.)--Uniformed Services University of the Health Sciences, 2005. / Typescript (photocopy).
49

Estudo das alterações no desenvolvimento, no comportamento e na bioquímica cerebral de ratos machos adultos expostos à poluição atmosférica ambiental durante a fase intra-uterina e o período de lactação / Study of the alterations in the development, behavior and cerebral biochemistry of male rats exposed to the environmental atmospheric pollution in the intra-uterine phase

Zanchi, Ana Claudia Tedesco 16 April 2010 (has links)
Estudos experimentais feitos em nosso laboratório comprovaram que a inalação de material particulado proveniente da queima de combustíveis fósseis utilizados em siderurgia pelos ratos adultos diminuiu a atividade motora dos animais no campo aberto. Além disso, provamos que os ratos habituaram ao ambiente desse teste, o que significa que a inalação desse tipo de material não provocou variação em termos de aprendizado simples. Uma das causas da alteração no comportamento em relação à motricidade seria o estresse oxidativo causado pelo material particulado no estriado e cerebelo desses animais. Entretanto, em nossa cidade não existem estudos que demonstrem a estreita associação entre inalação de poluentes, estresse oxidativo e alterações comportamentais. Baseados nos nossos trabalhos anteriores e na literatura, nosso objetivo foi investigar se a poluição atmosférica a nível ambiental durante as fases pré e pós-natal alteraria a memória discriminativa de curta-duração e a memória espacial. Além disso, avaliamos o papel do estresse oxidativo como o mecanismo propulsor dessas mudanças de comportamento. Para tal, ratas prenhas foram expostas ao ar filtrado e ao ar não filtrado durante os 21 dias de gestação. Ao final do período de amamentação, os machos foram separados e subdividos em 4 grupos experimentais (n=24): 1) Filtrado: nasceu e viveu em ambiente cujo ar era filtrado, 2) NFF: nasceu em ambiente cujo ar era não filtrado e viveu a partir do 21o dia do pós-natal no ambiente com ar filtrado, 3) FNF: nasceu sob ar filtrado e viveu a partir do 21o dia do pós-natal sob ar não filtrado, 4)NF: nasceu e viveu em ambiente cujo ar era não filtrado. Os animais ficaram expostos a poluição por 150 dias. Os animais foram divididos em 3 lotes: lote 1: n=6 animais por grupo; após anestesia profunda, os animais foram perfundidos com soro fisiológico seguido de paraformaldeído 4%, o encéfalo foi retirado e dissecado em córtex, hipocampo e estriado para análises histológicas por técnicas estereológicas; lote 2: n=12 ratos por grupo; aplicação dos testes comportamentais; um dia após os testes, esses animais foram eutanasiados por decapitação, o encéfalo retirado e dissecado da mesma forma citada anteriormente para análise de estresse oxidativo; lote 3: n=6 animais por grupo; os animais foram decapitados e o sangue troncular coletado para análises de elementos traço tóxicos e essenciais no sangue total. O córtex apresentou lipoperoxidação no grupo NF quando comparado aos outros grupos, assim como uma alta concentração de Cd no sangue. O grupo NFF apresentou uma maior concentração de Cu, Se e Zn no sangue em relação aos demais. Em relação à memória discriminativa de curta-duração, houve uma diminuição no grupo NF em relação aos demais grupos. No hipocampo e estriado, foi observado aumento da lipoperoxidação nos grupos FNF e NF, respectivamente, quando comparado aos outros grupos. Quanto à memória espacial, não houve diferença estatisticamente significativa entre os grupos. Primeiramente, como pudemos observar, o cada estrutura encefálica apresenta uma resposta ao estresse oxidativo. O córtex do grupo NF apresentou aumento de lipoperoxidação. Como se sabe, o Cd é feto tóxico e passa via transplacentária adsorvido ao material particulado inalado pela mãe. No caso do grupo NF, o Cd possivelmente deslocou o Zn do sítio ativo da enzima CuZn superóxido dismutase formando forma inativada da mesma. O Cd, também, forma conjugado com duas moléculas de glutationa reduzida a fim de ser excretado pela bile. Isso reduz a sua capacidade antioxidante. Esse elemento traço desloca o Fe e o Cu dos sítios ativos das suas proteínas de armazenamento, a ferritina e a ceruplasmina, respectivamente. Esses dois elementos ficam livres para catalisar a reação de Fenton cujo produto é o radical hidroxil, extremamente tóxico para o organismo. O grupo NF apresentou uma diminuição na capacidade de discriminar dois objetos diferentes. Provavelmente, o Cd agiu de forma indireta diminuindo a capacidade antioxidante da CuZn superóxido dismutase e da glutationa, além de liberar Fe e Cu e aumentar a produção de radical hidroxil. O aumento da lipoperoxidação causado pelo Cd pode ser o mecanismo responsável pela perda desse tipo de memória. Entretanto, o grupo NFF, cuja exposição à poluição foi na fase pré-natal, não apresentou aumento na lipoperoxidação. Possivelmente, a alta concentração dos elementos traço essenciais, Cu, Zn e Se aumentou a atividade das enzimas CuZn superóxidodismutase e glutationa peroxidase, respectivamente, o que evitou danos oxidativos durante o período intra-uterino. O grupo FNF apresentou aumento de lipoperoxidação no hipocampo, mas não houve diferença na memória espacial testada com o labirinto de Morris modificado. Portanto, considerando todos os achados, concluímos que, possivelmente, o aumento da lipoperoxidação causado indiretamente pelo Cd pode ser um dos mecanismos responsáveis pela perda da capacidade da memória discriminativa de curta-duração. Além disso, os elementos traço essenciais exercem uma proteção via aumento das defesas antioxidantes dos animais que nasceram em ambiente poluído e, após 21 dias de vida, foram transferidos para o ambiente com o ar filtrado, o que demonstra, provavelmente, a existência de mecanismos antioxidantes de adaptação em ambientes inóspitos como forma de proteção contra o agente agressor durante o desenvolvimento do embrião. / Experimental studies done at our laboratory demonstrated that the inhalation of residual oil fly ash by the adult rats decreased motor activity of the animals in the open-field test. Additionaly, we showed that rats which inhalated residual oil fly ash preserved its habituation capacity. In this study, oxidative stress in striatum and cerebellum might be the cause of motor activity alterations. However, there were any studies about air pollution and behavioral alterations in Porto Alegre. Based on our previous works and in the literature, our objective was to investigate if the exposure to air pollution during intrauterine and lactation periods would damage the short term discriminative and spatial memories and if the mechanisms would be dependent of oxidants. For such, female pregnant rats were exposed to the filtered air and to the non filtered air during the 21 days of gestation. At the end of the breast-feeding period, the males were separate and divided in 4 experimental groups (n =24): 1) Filtered (F): - pre and post-natal exposure until adulthood in filtered air; 2) non filtered/filtered air (NFF): pre-natal period in non-filtered air until PND21 and post-natal in filtered air until adulthood; 3) filtered air/non-filtered air (FNF): pre-natal period in filtered air until PND 21 and post-natal period in non-filtered air until adulthood; 4) non filtered air (NF): pre and post-natal periods in non-filtered air.The animals were exposed the pollution for 150 days. The animals were divided in 3 lots: lot 1: n=6 animals per group; after anesthesia, the animals were perfused with saline solution following by paraformaldehyde 4%, the brain was removed and dissected in cortex, hippocampus and striatum for histological analyses by stereological techniques; lot 2: n=12 rats per group; submitted to behavioral tests; one day after the tests, those animals were euthanized by decapitation, the brain was removed and dissected in the same way mentioned previously for oxidative stress analysis; lot 3: 6 animals per group; the animals were decapitated and the troncular blood was collected to analyze the toxic and the essential trace elements. The cortex presented lipoperoxidation in NF group when compared to other groups, as well as a high concentration of Cd in the blood. The group NFF presented higher blood concentration of Cu, Se and Zn when compared to other groups. There was a decrease in the discriminative capacity in the group NF when compared to other groups. In the hippocampus and striatum, increases of lipidperoxidation were observed in the groups FNF and NF, respectively, when compared to other groups. Spatial memory of all groups was preserved. We observed the each brain structure reacts in a different way to oxidative stress. The NF cortex group presented an increased of lipidperoxidation. In this group, there was higher Cd blood concentration, which passes through placenta and it is fetotoxic. It might be possible that Cd dislocated Zn of the active site of CuZn superóxido dismutase resulting in inactive forms of this enzyme. The Cd also depletes reduced glutathione. Moreover, Cd may dislocate the Fe and Cu from its storage proteins to react with oxygen peroxide increasing the hydroxyl radical production by Fenton reaction. The group NF presented a decrease in the capacity to discriminate two different objects. Cd may act in an indirect way reducing the antioxidant capacity of CuZn superxidodismutase and of the glutathione and increasing the hydroxyl radical production. Lipoperoxidation in NF cortex caused by the Cd may be one of the mechanisms which explain the loss of discriminative capacity. However, the group NFF, whose air pollution exposure was in the pre-natal period, did not present increase of lipidperoxidation. The higher concentrations of essential trace elements (Cu, Se and Zn) may protect this group against oxidative stress. These elements are cofactor of antioxidants enzymes, superoxidodismutase and glutathione peroxidase and increased its activities during the intra-uterine exposure to air pollution. The group FNF presented lipidperoxidation increase in the hippocampus, but there was no difference in the spatial memory tested with Morris\' maze. Therefore, considering our data, we suggested that the increase of lipidperoxidation caused indirectly by Cd, which was adsorbed in particulate matter surface, may be one of the mechanisms which explain the loss of short-term discriminative memory
50

Estudo das alterações no desenvolvimento, no comportamento e na bioquímica cerebral de ratos machos adultos expostos à poluição atmosférica ambiental durante a fase intra-uterina e o período de lactação / Study of the alterations in the development, behavior and cerebral biochemistry of male rats exposed to the environmental atmospheric pollution in the intra-uterine phase

Ana Claudia Tedesco Zanchi 16 April 2010 (has links)
Estudos experimentais feitos em nosso laboratório comprovaram que a inalação de material particulado proveniente da queima de combustíveis fósseis utilizados em siderurgia pelos ratos adultos diminuiu a atividade motora dos animais no campo aberto. Além disso, provamos que os ratos habituaram ao ambiente desse teste, o que significa que a inalação desse tipo de material não provocou variação em termos de aprendizado simples. Uma das causas da alteração no comportamento em relação à motricidade seria o estresse oxidativo causado pelo material particulado no estriado e cerebelo desses animais. Entretanto, em nossa cidade não existem estudos que demonstrem a estreita associação entre inalação de poluentes, estresse oxidativo e alterações comportamentais. Baseados nos nossos trabalhos anteriores e na literatura, nosso objetivo foi investigar se a poluição atmosférica a nível ambiental durante as fases pré e pós-natal alteraria a memória discriminativa de curta-duração e a memória espacial. Além disso, avaliamos o papel do estresse oxidativo como o mecanismo propulsor dessas mudanças de comportamento. Para tal, ratas prenhas foram expostas ao ar filtrado e ao ar não filtrado durante os 21 dias de gestação. Ao final do período de amamentação, os machos foram separados e subdividos em 4 grupos experimentais (n=24): 1) Filtrado: nasceu e viveu em ambiente cujo ar era filtrado, 2) NFF: nasceu em ambiente cujo ar era não filtrado e viveu a partir do 21o dia do pós-natal no ambiente com ar filtrado, 3) FNF: nasceu sob ar filtrado e viveu a partir do 21o dia do pós-natal sob ar não filtrado, 4)NF: nasceu e viveu em ambiente cujo ar era não filtrado. Os animais ficaram expostos a poluição por 150 dias. Os animais foram divididos em 3 lotes: lote 1: n=6 animais por grupo; após anestesia profunda, os animais foram perfundidos com soro fisiológico seguido de paraformaldeído 4%, o encéfalo foi retirado e dissecado em córtex, hipocampo e estriado para análises histológicas por técnicas estereológicas; lote 2: n=12 ratos por grupo; aplicação dos testes comportamentais; um dia após os testes, esses animais foram eutanasiados por decapitação, o encéfalo retirado e dissecado da mesma forma citada anteriormente para análise de estresse oxidativo; lote 3: n=6 animais por grupo; os animais foram decapitados e o sangue troncular coletado para análises de elementos traço tóxicos e essenciais no sangue total. O córtex apresentou lipoperoxidação no grupo NF quando comparado aos outros grupos, assim como uma alta concentração de Cd no sangue. O grupo NFF apresentou uma maior concentração de Cu, Se e Zn no sangue em relação aos demais. Em relação à memória discriminativa de curta-duração, houve uma diminuição no grupo NF em relação aos demais grupos. No hipocampo e estriado, foi observado aumento da lipoperoxidação nos grupos FNF e NF, respectivamente, quando comparado aos outros grupos. Quanto à memória espacial, não houve diferença estatisticamente significativa entre os grupos. Primeiramente, como pudemos observar, o cada estrutura encefálica apresenta uma resposta ao estresse oxidativo. O córtex do grupo NF apresentou aumento de lipoperoxidação. Como se sabe, o Cd é feto tóxico e passa via transplacentária adsorvido ao material particulado inalado pela mãe. No caso do grupo NF, o Cd possivelmente deslocou o Zn do sítio ativo da enzima CuZn superóxido dismutase formando forma inativada da mesma. O Cd, também, forma conjugado com duas moléculas de glutationa reduzida a fim de ser excretado pela bile. Isso reduz a sua capacidade antioxidante. Esse elemento traço desloca o Fe e o Cu dos sítios ativos das suas proteínas de armazenamento, a ferritina e a ceruplasmina, respectivamente. Esses dois elementos ficam livres para catalisar a reação de Fenton cujo produto é o radical hidroxil, extremamente tóxico para o organismo. O grupo NF apresentou uma diminuição na capacidade de discriminar dois objetos diferentes. Provavelmente, o Cd agiu de forma indireta diminuindo a capacidade antioxidante da CuZn superóxido dismutase e da glutationa, além de liberar Fe e Cu e aumentar a produção de radical hidroxil. O aumento da lipoperoxidação causado pelo Cd pode ser o mecanismo responsável pela perda desse tipo de memória. Entretanto, o grupo NFF, cuja exposição à poluição foi na fase pré-natal, não apresentou aumento na lipoperoxidação. Possivelmente, a alta concentração dos elementos traço essenciais, Cu, Zn e Se aumentou a atividade das enzimas CuZn superóxidodismutase e glutationa peroxidase, respectivamente, o que evitou danos oxidativos durante o período intra-uterino. O grupo FNF apresentou aumento de lipoperoxidação no hipocampo, mas não houve diferença na memória espacial testada com o labirinto de Morris modificado. Portanto, considerando todos os achados, concluímos que, possivelmente, o aumento da lipoperoxidação causado indiretamente pelo Cd pode ser um dos mecanismos responsáveis pela perda da capacidade da memória discriminativa de curta-duração. Além disso, os elementos traço essenciais exercem uma proteção via aumento das defesas antioxidantes dos animais que nasceram em ambiente poluído e, após 21 dias de vida, foram transferidos para o ambiente com o ar filtrado, o que demonstra, provavelmente, a existência de mecanismos antioxidantes de adaptação em ambientes inóspitos como forma de proteção contra o agente agressor durante o desenvolvimento do embrião. / Experimental studies done at our laboratory demonstrated that the inhalation of residual oil fly ash by the adult rats decreased motor activity of the animals in the open-field test. Additionaly, we showed that rats which inhalated residual oil fly ash preserved its habituation capacity. In this study, oxidative stress in striatum and cerebellum might be the cause of motor activity alterations. However, there were any studies about air pollution and behavioral alterations in Porto Alegre. Based on our previous works and in the literature, our objective was to investigate if the exposure to air pollution during intrauterine and lactation periods would damage the short term discriminative and spatial memories and if the mechanisms would be dependent of oxidants. For such, female pregnant rats were exposed to the filtered air and to the non filtered air during the 21 days of gestation. At the end of the breast-feeding period, the males were separate and divided in 4 experimental groups (n =24): 1) Filtered (F): - pre and post-natal exposure until adulthood in filtered air; 2) non filtered/filtered air (NFF): pre-natal period in non-filtered air until PND21 and post-natal in filtered air until adulthood; 3) filtered air/non-filtered air (FNF): pre-natal period in filtered air until PND 21 and post-natal period in non-filtered air until adulthood; 4) non filtered air (NF): pre and post-natal periods in non-filtered air.The animals were exposed the pollution for 150 days. The animals were divided in 3 lots: lot 1: n=6 animals per group; after anesthesia, the animals were perfused with saline solution following by paraformaldehyde 4%, the brain was removed and dissected in cortex, hippocampus and striatum for histological analyses by stereological techniques; lot 2: n=12 rats per group; submitted to behavioral tests; one day after the tests, those animals were euthanized by decapitation, the brain was removed and dissected in the same way mentioned previously for oxidative stress analysis; lot 3: 6 animals per group; the animals were decapitated and the troncular blood was collected to analyze the toxic and the essential trace elements. The cortex presented lipoperoxidation in NF group when compared to other groups, as well as a high concentration of Cd in the blood. The group NFF presented higher blood concentration of Cu, Se and Zn when compared to other groups. There was a decrease in the discriminative capacity in the group NF when compared to other groups. In the hippocampus and striatum, increases of lipidperoxidation were observed in the groups FNF and NF, respectively, when compared to other groups. Spatial memory of all groups was preserved. We observed the each brain structure reacts in a different way to oxidative stress. The NF cortex group presented an increased of lipidperoxidation. In this group, there was higher Cd blood concentration, which passes through placenta and it is fetotoxic. It might be possible that Cd dislocated Zn of the active site of CuZn superóxido dismutase resulting in inactive forms of this enzyme. The Cd also depletes reduced glutathione. Moreover, Cd may dislocate the Fe and Cu from its storage proteins to react with oxygen peroxide increasing the hydroxyl radical production by Fenton reaction. The group NF presented a decrease in the capacity to discriminate two different objects. Cd may act in an indirect way reducing the antioxidant capacity of CuZn superxidodismutase and of the glutathione and increasing the hydroxyl radical production. Lipoperoxidation in NF cortex caused by the Cd may be one of the mechanisms which explain the loss of discriminative capacity. However, the group NFF, whose air pollution exposure was in the pre-natal period, did not present increase of lipidperoxidation. The higher concentrations of essential trace elements (Cu, Se and Zn) may protect this group against oxidative stress. These elements are cofactor of antioxidants enzymes, superoxidodismutase and glutathione peroxidase and increased its activities during the intra-uterine exposure to air pollution. The group FNF presented lipidperoxidation increase in the hippocampus, but there was no difference in the spatial memory tested with Morris\' maze. Therefore, considering our data, we suggested that the increase of lipidperoxidation caused indirectly by Cd, which was adsorbed in particulate matter surface, may be one of the mechanisms which explain the loss of short-term discriminative memory

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