Made available in DSpace on 2015-03-03T11:52:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-22Bitstream added on 2015-03-03T12:06:19Z : No. of bitstreams: 1 000810790.pdf: 680944 bytes, checksum: 5bebeac6900ff8428ba55baf3da491f6 (MD5) / Alguns fatores relacionados a produção de leite, como ambiente e manejo, podem alterar o bem estar dos animais provocando estresse e trazendo prejuízos a produção. Daí a importância do estudo do comportamento animal, sua relação com o aumento do cortisol e seus efeitos na produção leiteira. Dez vacas Girolanda e seus bezerros foram avaliados durante as primeiras catorze semanas de lactação. Foram feitas análises comportamentais e colheita de fezes semanais para determinação do nível de cortisol das vacas e dos bezerros. As observações e medidas dos comportamentos foram realizadas após o parto, durante 3 dias por semana, nas 14 primeiras semanas de lactação. Foram analisadas as posições e comportamentos alimentares e maternos das vacas e o comportamento filial dos bezerros. Os valores de cortisol nas fezes para os bezerros foram de 17,87 ng/g de fezes para o parto e 12,51 ng/g de fezes nas semanas após o parto. Os valores de cortisol nas fezes para as vacas foram de 11,71 ng/g de fezes para o parto e 7,59 ng/g de fezes nas semanas após o parto. Para bezerros foi verificada associação entre o cortisol e alguns dos comportamentos, com valores de correlação baixos (r² < 0,30) entre cortisol e Levanta-se, Anda, e Mama' e valores médios de correlação (r² < 0,30 e r² < 0,70) entre o cortisol e Deitado, Procura pelos tetos e 'Tenta mamar. Para vacas também foi verificada associação entre o cortisol mensurado nas fezes e alguns comportamentos maternos. Neste caso, foram encontrados valores de correlação baixos (r ²< 0,30) entre o cortisol e Facilita a mamada e valores médios de correlação (r² < 0,30 e r² < 0,70) entre o cortisol e Lambe a cria, Estimula a cria a mamar, Deixa mamar, Anda ou movimenta-se e Afasta-se da cria. As analises de regressão demonstraram que foi possível descrever equações preditorias que fornecem informações importantes sobre a relação cortisol e ... / Some factors related to milk production, such as environment management can alter the welfare of animals causing stress and damages to production. Hence, the importance of the study of animal behavior, its relation with increased cortisol and its effects on milk production. Ten girolando cows and their calves were evaluated during the first fourteen weeks of lactation. Behavioral analysis and collection of feces occured weekly stool to determine the level of cortisol in cows and calves. The observations and measurements of the behaviors were performed after delivery, for 3 days a week, in the first 14 weeks of lactation. Positions and eating behaviors and maternal cows and filial behavior of calves were analyzed. The levels of cortisol in the feces for calves were 17.87 ng / g feces in parturition and 12.51 ng / g of feces in the weeks after birth. The cortisol levels in stools for cows were 11.71 ng / g feces in parturition and 7.59 ng / g of feces in the weeks after birth. For calves, was association between cortisol and some of the behaviors with low correlation values (r ² <0.30) between cortisol and Rises, Come, and Nurse and average correlation (r ² <0 , 30 and r² <0.70) between cortisol and Lick, Search by ceilings and Tries to feed herself. For cows also was association between cortisol measured in stool and some maternal behaviors. In this case, low values of correlation (r ² <0.30) were found between cortisol and facilitates breastfeeding and average correlation (r ² <0.30 and r ² <0.70) between cortisol and Lick the calf, stimulates suckling , Lets calf , Walk or moving and Deviate creates the . The regression analysis showed that it was possible to describe preditorias equations that provide important information about the relationship cortisol and behavior of calves. Correlations in Lying dow, ises, Standing, searsh and Tries to feed herself were checked. For cows is possible to observe ...

abstract: Unanswered questions about the evolution of human gender abound and are salient across the anthropological disciplines and beyond. Did adult sex-typed behavioral tendencies actually evolve? If so, when? For what purpose? The best way to gain insight into the evolution of human gender is to understand the evolution and development of sex-typed behavior in comparative primate taxa. Captive research indicates that there are many proximate factors likely to shape the development of sex-typed behavior in non-human primates&mdash;prenatal and postnatal endocrinological experience, social experience, ecological factors, and their interactions. However, it is largely unknown how sex-typed behavior proceeds and is shaped by those factors in evolutionarily salient environments. This study investigated one&mdash;whether extrinsic sexually differentiated social interactions are likely influential in the development of adult sex-typed behavior in wild-living Lemur catta. Little is known about sex-typed development in this species or in strepsirrhines in general. This research therefore addresses an important phylogenetic gap in our understanding of primate sex-typed development. Behavioral observations were carried out on mixed cross-sectional sample of adult females (n=10), adult males (n=8), yearling females (n=4), yearling males (n=4), and newborn females (n=16) and males (n=14) at Beza Mahafaly Special Reserve in southwest Madagascar from September 2008 to August 2009. Twenty-three sex-typed behaviors were identified in adults using linear mixed effects models and models of group response profiles through time. Of those, only eight had a pre-pubertal developmental component. Infants did not exhibit any sex differences in behavior, but juveniles (prepubertal, weaned individuals) resembled adults in their (relatively few) patterns of expression of sex-typed behavior. Most adult sex-typed behaviors in this species apparently develop at or after puberty and may be under gonadal hormone control. Those that develop before puberty do not likely depend on extrinsic sexually differentiation social interactions for their development, because there is no clear evidence that infants and juvenile male and females are not treated differently by others according to sex. If sexually differentiated social interactions are important for sex-typed behavioral development in subadult ,italic>Lemur catta, they are likely intrinsically (rather than extrinsically) driven. / Dissertation/Thesis / Ph.D. Anthropology 2012

abstract: Colorful ornaments in animals often serve as sexually selected signals of quality. While pigment-based colors are well-studied in these regards, structural colors that result from the interaction of light with photonic nanostructures are comparatively understudied in terms of their consequences in social contexts, their costs of production, and even the best way to measure them. Iridescent colors are some of the most brilliant and conspicuous colors in nature, and I studied the measurement, condition-dependence, and signaling role of iridescence in Anna's hummingbirds (Calypte anna). While most animal colors are easily quantified using well-established spectrophotometric techniques, the unique characteristics of iridescent colors present challenges to measurement and opportunities to quantify novel color metrics. I designed and tested an apparatus for careful control and measurement of viewing geometry and highly repeatable measurements. These measurements could be used to accurately characterize individual variation in iridescent Anna's hummingbirds to examine their condition-dependence and signaling role. Next, I examined the literature published to date for evidence of condition-dependence of structural colors in birds. Using meta-analyses, I found that structural colors of all three types - white, ultra-violet/blue, and iridescence - are significantly condition-dependent, meaning that they can convey information about quality to conspecifics. I then investigated whether iridescent colors were condition-dependent in Anna's hummingbirds both in a field correlational study and in an experimental study. Throughout the year, I found that iridescent feathers in both male and female Anna's hummingbirds become less brilliant as they age. Color was not correlated with body condition in any age/sex group. However, iridescent coloration in male Anna's hummingbirds was significantly affected by experimental protein in the diet during feather growth, indicating that iridescent color may signal diet quality. Finally, I examined how iridescent colors were used to mediate social competitions in male and female Anna's hummingbirds. Surprisingly, males that were less colorful won significantly more contests than more colorful males, and colorful males received more aggression. Less colorful males may be attempting to drive away colorful neighbors that may be preferred mates. Female iridescent ornament size and color was highly variable, but did not influence contest outcomes or aggression. / Dissertation/Thesis / Ph.D. Biology 2012

Made available in DSpace on 2015-06-17T19:33:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-27. Added 1 bitstream(s) on 2015-06-18T12:47:53Z : No. of bitstreams: 1 000834769_20151227.pdf: 183649 bytes, checksum: c58891d7740f471736dae3c8dd8b54b2 (MD5) Bitstreams deleted on 2016-01-04T10:26:20Z: 000834769_20151227.pdf,. Added 1 bitstream(s) on 2016-01-04T10:28:14Z : No. of bitstreams: 1 000834769.pdf: 594314 bytes, checksum: 37ad3462d66db32c64b15134e1a32e4e (MD5) / Os objetivos deste estudo foram avaliar os efeitos da adoção de um conjunto de boas práticas de manejo no bem-estar de bezerros leiteiros, bem como avaliar os efeitos específicos da presença da mãe nas primeiras 24 horas e da estimulação tátil nesses animais. Para tanto foram realizados dois experimentos, onde no Experimento 1 foram avaliados 48 bezerros machos cruzados (Holandes x Gir x Jersey) e no Experimento 2, 48 bezerras fêmeas da raça Girolando, acompanhando, em ambos os experimentos, os bezerros desde o nascimento até os 120 dias de idade. No Experimento 1, foram adotados dois grupos de manejo: Manejo Controle (bezerros mantidos em casinhas tropicais/EMBRAPA durante todo o período de aleitamento e com desmama abrupta) e Boas Práticas de Manejo (BPM), composto por aleitamento em baldes com bicos, interação social entre os bezerros e tratador-bezerro, estimulação tátil e desmama progressiva. O experimento 2 foi composto por 4 grupos de manejo, com todas as bezerras manejadas com BPM, avaliando-se os efeitos da presença da mãe nas primeiras 24 de horas e da estimulação tátil até o desmame, definindo os seguintes grupos de manejo: TM= as bezerras tiveram a presença da mãe nas primeiras 24 horas de vida; TME= como TM, mas com a adoção de estimulação tátil; TO= as bezerras foram apartadas das mães imediatamente após o nascimento, sendo que estas não tiveram nenhum contanto com suas mães após o parto; TOE= como TO, mas com adoção de estimulação tátil. Para avaliação do bem-estar dos bezerros, em ambos os estudos, foram considerados indicadores de saúde: fisiológicos, comportamentais e de desempenho. Os efeitos dos grupos de manejos sobre os indicadores de bem-estar animal que apresentaram distribuição normal foram avaliados com análises de variância (ANOVA) com medidas repetidas no tempo usando o método da máxima verosimilhança restrita (REML), utilizando o procedimento MIXED do SAS. As... / The aims of this study were to evaluate the adoption of good practices of handling effects on dairy calves welfare, and to evaluate the specific effects of the mother's presence in the first 24 hours and the tactile stimulation in these animals. Therefore, we carried out two experiments, Experiment 1 were evaluated 48 male calves crossed (Holstein x Gir x Jersey) and the Experiment 2, 48 calves female Girolando breed. In both experiments, the calves were watching from birth to the 120 days of age. In the Experiment 1, were adopted handling groups: Control Handling (dairy calves in tropical houses during whole suckling period using abrupt weaning) and the Good Practice of Handling (GPH), composed by suckling in teats buckets, opportunity for to express social behaviour, positive interaction human-calf, tactile stimulation and gradual weaning). Experiment 2 consisted of four handling groups, all the calves were handling with GPH, evaluating the effects of the mother's presence in the first 24 hours and tactile stimulation until weaning, to knowledge: MH = the calves had the mother's presence in the first 24 hours of life; MSH = as MH, but with the adoption of tactile stimulation; OH = calves were separated immediately from mother after birth (without any contact with cow); OSH= as OH, but with the adoption of tactile stimulation. To evaluate the dairy calves' welfare, in both studies, were considered the health, physiological, behavioral and performance indicators. The effects of handling groups on animal welfare indicators were evaluated with normal distribution using analysis of variance (ANOVA) with repeated measures using the restricted maximum likelihood (REML) by the MIXED procedure of SAS. Means were compared by the Tukey test, with P values <0.10 for deletion and P <0.05 for significance. For the welfare's indicators presented binomial distribution was used the method of restricted maximum likelihood (REML), with application ...

abstract: Smoking remains the leading cause of preventable death in the United States, and early initiation is associated with greater difficulty quitting. Among adolescent smokers, those with attention-deficit hyperactivity disorder (ADHD), characterized by difficulties associated with impulsivity, hyperactivity, and inattention, smoke at nearly twice the rate of their peers. Although cigarette smoking is highly addictive, nicotine is a relatively weak primary reinforcer, spurring research on other potential targets that may maintain smoking, including the potential benefits of nicotine on attention, inhibition, and reinforcer efficacy. The present study employs the most prevalent rodent model of ADHD, the spontaneously hypertensive rat (SHR) and its control comparison Wistar Kyoto (WKY) to examine the effects of acute and chronic subcutaneous nicotine injections on performance in three operant response inhibition paradigms. Functional activation in select regions of the prefrontal cortex and striatum was also explored. Acute (0.1, 0.3, 0.6 mg/kg) and chronic (0.3 mg/kg) nicotine increased impulsive responding regardless of strain, dose, or operant schedule. Dose-dependent decreases in latency to initiate the task were also observed. SHR receiving daily nicotine injections showed less activation in the nucleus accumbens shell compared to saline controls. Despite close similarities, one of the three operant tasks did not detect response inhibition deficits in SHR relative to WKY. A closer examination of these tasks may highlight critical components involved in the amelioration of response inhibition deficits. / Dissertation/Thesis / Doctoral Dissertation Psychology 2014

Orientador: Guilherme de Camargo Ferraz / Banca: Herbert Gustavo Simões / Banca: Luciane Helena Gargaglioni Batalhão / Resumo: Objetivo: investigar o comportamento, concentrações de corticosterona, lactato e glicose de ratos Wistar submetidos a um protocolo de "overtraining" (PO) para o desenvolvimento de "Functional" (FOR) ou "Nonfunctional Overreaching" (NFOR). Métodos: inicialmente a amostragem de indivíduos foi de 49. O grupo controle (C, n= 16) realizou um programa de condicionamento leve (1 sessão/dia/ 2x/sem./12 m.min-1). Os outros ratos (n= 33) foram submetidos ao PO, com duração de 12 sem., prescrito para produzir um desequilíbrio entre as sessões de exercício e o período de recuperação. Em 8 sem. foram realizadas sessões de treino diárias, por 5 d consecutivos seguidas por 2 d de recuperação. Nas 4 sem. subsequentes, houve aumento da frequência de treino (2, 3, 4 e 4 x/d) e redução do tempo de recuperação entre as sessões (4, 3, 2 e 2 h). Para avaliação da aptidão física, os ratos foram submetidos a sete testes de esforço máximo (T-máx) durante e dois testes após o PO. Dois grupos foram identificados pela diferença da inclinação (α) obtida a partir da regressão linear dos desempenhos individuais nos Tmáx-3, 4, 5, 6 e 7. Ratos NFOR (n= 14) tiveram α= < -0.98. Analisou-se a recuperação passiva de 2 sem., sendo realizado testes de Campo Aberto (CA) e Labirinto em Cruz Elevado (LCE). Neste período, dois Tmáxs (8 e 9) foram realizados para verificação da continuidade das condições FOR e NFOR. Em Tmáx-2, Tmáx-6 e Tmáx-9 realizaram-se coletas sanguíneas para quantificação das concentrações plasmát... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: To investigate the behavior, corticosterone and lactate concentrations of Wistar rats submitted to an overtraining protocol (OP) for the development of functional (FOR) or nonfunctional overreaching (NFOR). Methods: Sampling of rats was 49. The control group (C, n= 16) performed a mild conditioning program (1 session/day / 2x/wk/12 m.min-1). The other rats, n= 33, were submitted to 12-week OP prescribed to produce an imbalance between the exercise sessions and the recovery period. In 8 wks. daily training sessions were performed for 5 consecutive d followed by 2 d of recovery. In the following 4 wks. (2, 3, 4 and 4 x / d) there was an increase in training frequency and reduction of recovery time between sessions (4, 3, 2 and 2 h). To evaluate physical fitness, the rats were submitted to seven maximum tests (Tmax) during and two tests after the PO. Two groups were identified by the slope difference (α) obtained from the linear regression of individual performances at Tmax-3, 4, 5, 6 and 7. NFOR rats (n= 14) had α = -0.98. Passive recovery of 2 wks was analyzed, and Open Field (OF) and Elevated Plus Maze (EPM) tests were performed. In this period, 2 Tmaxs (8 and 9) were performed to verify the continuity of FOR and NFOR conditions. Blood samples were collected for Tmax-2, Tmax-6 and Tmax-9 for the quantification of plasma lactate concentrations ([lac]before and [lac]after) and glucose ([glic]before and [glic]after). Corticosterone was measured at rest and after Tmax-7 and 9, ([cort]rest and [cort]after). Adrenal glands were collected and weighed. For statistical analysis one-way ANOVA and repeated measures ANOVA, paired and unpaired Student's t-tests and a Pearson correlation were performed (P < 0.05). Results: NFOR and FOR had an increase in performance from Tmax-2 (303.8±13.8, 294.3±18.9 and 190.2±12.2 kg.m, respectively). The NFOR group ... (Complete abstract click electronic access below) / Mestre

Orientador: Hirasilva Borba / Coorientador: Pedro Alves de Souza / Banca: Marcos Chiquitelli Neto / Banca: Maria Lúcia Pereira Lima / Banca: Wignez Henrique / Banca: Otávio Rodrigues Machado Neto / Resumo: O objetivo nesse estudo foi identificar, dentre várias boas práticas recomendadas para as plantas frigoríficas, quais causam efeitos positivos ou negativos em questões comportamentais dos animais e medidas de qualidade de carcaça. Como objetivos específicos buscamos: 1) Verificar a eficácia da utilização de substratos no piso dos currais; 2) encontrar o parâmetro para cálculo do melhor espaçamento dentro dos currais do frigorífico. Para atendimento do objetivo 1 foi realizado experimento em um frigorífico no interior paulista durante 11 dias, isolando a maior quantidade de fontes de variações, a fim de testar a diferença no comportamento dos animais e na qualidade da carcaça dos bovinos abatidos quando utilizados 3 tipos diferentes de pisos (bagaço de cana, borracha ou concreto). No tratamento em que animais possuíam piso coberto por bagaço de cana, o ato de deitar foi mais frequente do que os tratamentos onde foram utilizados os outros dois tipos de piso; porém, essa maior frequência do comportamento não foi suficiente para propiciar uma diferença significativa na quantidade de hematomas presentes nas carcaças e para alterar o pH final das carcaças. A desvantagem para a utilização do bagaço ocorreu quando se avaliou frequência de brigas e montas, além da quantidade de água e tempo necessários para limpeza dos currais, aumentando assim problemas relacionados à sustentabilidade, bem como elevando os custos de abate dos bovinos. Para estudar o melhor espaçamento nos currais dos frigoríficos (objetivo 2), durante 26 dias de abate, foram registrados peso vivo médio dos animais que foram colocados em cada curral do frigorífico, quantidade de animais e espaçamento disponível em cada curral para cada animal. A quantidade de hematomas nas carcaças e pH após 24h de resfriamento das mesmas também foram registrados. Esses dados foram utilizados para determinar a... / Abstract: The main objective was to indentify, among many good practices recommended at slaughterhouses, which one can cause positive or negative effects over animal behaviour and carcass quality. As a specific aim we evaluated: 1) The efficiency of using bedding in the lairage for animals that stay overnight; 2) The parameter to calculate the best stocking density in the lairage. To achieve the first objective, an experiment was run in a slaughterhouse in the countryside of São Paulo, Brazil, during eleven days. All possible factors of variations were minimized to be possible to test the difference of behaviour and parameters of carcass quality of beef cattle, using three different types of flooring (sugarcane residue, rubber matting and concrete). It was found that animals that had sugarcane residue as bedding overnight showed more lying behaviour than the ones that had rubber matting or concrete flooring available. The bigger time lying was not sufficient to affect carcass parameters. In the other hand, the corrals that were covered by sugarcane residue presented more agonistics behavior like fighting and mounting and wasted much more time and water to clean up, increasing sustainability problems as well as increasing cost of production. When studying stocking density in the lairage (objective 2), records were made during 26 days of slaughter, appointing the average live weight of animals that were lairaged in each pen, number of animals and space available for each animal. The number of bruises in the carcasses was also measured, as well as ultimate pH after 24 hours of chilling (pHu). Those measurements were used to determine the equation able to predict the best space for the animals lairaged. Low correlations were found between density and those parameters, as well as low values for R2 for the regression equation, which made it possible to conclude that stocking density at the ... / Doutor

abstract: Ethinyl estradiol, (EE) a synthetic, orally bio-available estrogen, is the most commonly prescribed form of estrogen in oral contraceptives (Shively, C., 1998), and is found in at least 30 different contraceptive formulations currently prescribed to women (Curtis et al., 2005). EE is also used in hormone therapies prescribed to menopausal women, such as FemhrtTM (Simon et al., 2003). Thus, EE is prescribed clinically to women at ages ranging from puberty through reproductive senescence. Here, in two separate studies, the cognitive effects of cyclic or tonic EE administration following ovariectomy (Ovx) were evaluated in young, female rats. Study I assessed the cognitive effects of low and high doses of EE, delivered tonically via a subcutaneous osmotic pump. Study II evaluated the cognitive effects of low, medium, and high doses of EE administered via a daily subcutaneous injection. For these studies, the low and medium doses correspond to the range of doses currently used in clinical formulations, and the high dose corresponds to the range of doses prescribed to a generation of women between 1960 and 1970, when oral contraceptives first became available. For each study, cognition was evaluated with a battery of maze tasks tapping several domains of spatial learning and memory. At the highest dose, EE treatment impaired multiple domains of spatial memory relative to vehicle treatment, regardless of administration method. When given cyclically at the low and medium doses, EE did not impact working memory, but transiently impaired reference memory during the learning phase of testing. Of the doses and regimens tested here, only EE at the highest dose impaired several domains of memory; this was seen for both cyclic and tonic regimens. Cyclic and tonic delivery of low EE, a dose that corresponds to doses used in the clinic today, resulted in transient and null impairments, respectively, on cognition. / Dissertation/Thesis / M.A. Psychology 2012

abstract: The coordination of group behavior in the social insects is representative of a broader phenomenon in nature, emergent biological complexity. In such systems, it is believed that large-scale patterns result from the interaction of relatively simple subunits. This dissertation involved the study of one such system: the social foraging of the ant Temnothorax rugatulus. Physically tiny with small population sizes, these cavity-dwelling ants provide a good model system to explore the mechanisms and ultimate origins of collective behavior in insect societies. My studies showed that colonies robustly exploit sugar water. Given a choice between feeders unequal in quality, colonies allocate more foragers to the better feeder. If the feeders change in quality, colonies are able to reallocate their foragers to the new location of the better feeder. These qualities of flexibility and allocation could be explained by the nature of positive feedback (tandem run recruitment) that these ants use. By observing foraging colonies with paint-marked ants, I was able to determine the `rules' that individuals follow: foragers recruit more and give up less when they find a better food source. By altering the nutritional condition of colonies, I found that these rules are flexible - attuned to the colony state. In starved colonies, individual ants are more likely to explore and recruit to food sources than in well-fed colonies. Similar to honeybees, Temmnothorax foragers appear to modulate their exploitation and recruitment behavior in response to environmental and social cues. Finally, I explored the influence of ecology (resource distribution) on the foraging success of colonies. Larger colonies showed increased consistency and a greater rate of harvest than smaller colonies, but this advantage was mediated by the distribution of resources. While patchy or rare food sources exaggerated the relative success of large colonies, regularly (or easily found) distributions leveled the playing field for smaller colonies. Social foraging in ant societies can best be understood when we view the colony as a single organism and the phenotype - group size, communication, and individual behavior - as integrated components of a homeostatic unit. / Dissertation/Thesis / Ph.D. Biology 2014

A hipótese de \"manipulação comportamental\" supõe que um parasito pode alterar o comportamento de seu hospedeiro visando aumentar a probabilidade de completar seu ciclo evolutivo. Tais alterações aumentariam a taxa de transmissão hospedeirohospedeiro, assegurando ao parasito ou a seus propágulos o encontro de novo hospedeiro. A possibilidade de infecções parasitárias provocarem mudanças comportamentais em seus hospedeiros e a elevada frequência com que o acometimento de seres humanos por larvas de Toxocara e cistos de Toxoplasma ocorre, têm chamado à atenção de pesquisadores interessados no estudo das relações hospedeiro-parasita. Na infecção por Toxoplasma gondii e Toxocara canis, cistos e larvas estão presentes em diversos locais anatômicos incluindo musculatura, coração, pulmões, olhos e cérebro. A presença de parasitos no cérebro dá oportunidade de manipulação do comportamento do hospedeiro. Entretanto, não se sabe qual ou quais mecanismos estão envolvidos no processo de manipulação do comportamento. Os objetivos do presente estudo foram verificar alterações na ansiedade, medo, memória e aprendizagem de Rattus norvegicus experimentalmente infectados por Toxocara canis e/ou Toxoplasma gondii em dois períodos após infecção, bem como a localização das larvas e cistos e presença de placas beta amiloide ( A) na região do hipocampo no tecido cerebral desses roedores corado pela técnica de Hematoxilina e Eosina (HE), e Vermelho de Congo, respectivamente. Foram utilizadas 40 exemplares fêmeas da espécie Rattus norvegicus, com seis a oito semanas. Os animais foram divididos em quatro grupos: Toxocara - 10 ratos infectados com 300 ovos de Toxocara canis, Toxoplasma -10 ratos infectados com 10 cistos de Toxoplasma gondii, Infecção dupla - 10 ratos infectados com 300 ovos de Toxocara canis e 10 cistos de Toxoplasma gondii, e controle - 10 ratos sem infecção. Nos dias 40, 41, 70 e 71 após a infecção, os animais dos grupos infectados e controle foram submetidos à avaliação no Labirinto em Cruz Elevado e Campo aberto. Aos 120 após infecção foi feita avaliação da memória, aprendizado e aversão a urina de gato dos animais no Labirinto de Barnes. No final das análises comportamentais os animais foram levados a eutanásia para retirada do cérebro e confecção dos cortes histológicos preparados em HE e Vermelho de Congo. Os resultados mostraram efeito ansiolítico para ambas as infecções, principalmente para Toxoplasma gondii. Não houve comprometimento da memória e aprendizado no LB, porém os animais infectados por Toxocara canis ou Toxoplasma gondii apresentaram menor tempo para encontrar a toca com urina e entrar nela. A leitura dos cortes histológicos corados com HE mostraram larvas de Toxocara canis e cistos de Toxoplasma gondii em regiões do sistema nervoso central dos animais relacionadas com memória e aprendizado. As lâminas coradas com Vermelho de Congo apresentaram placas beta amiloides ( A) em metade dos animais infectados por Toxoplasma gondii. Conclui-se que a infecção por ambos os parasitos apresenta efeito ansiolítico quando ocorre infecção única. Quando a Infecção ocorre concomitantemente há modulação no comportamento. Além disso, ratas infectadas com infecção única apresentam-se menos aversivas à urina de gatos. / The hypothesis of \"behavioral manipulation\" states that a parasite can change the behavior of its host specifically to improve the chances of completing its life cycle. It means the increase of transmission host to host and ensures that the parasite or their propagules are released in appropriate place increasing their survival . The possibility of parasitic infections to cause behavioral changes in their hosts and the high frequency which the involvement of humans by larvae of Toxocara and Toxoplasma cysts occur , have called the attention of researchers interested in the study of host/parasite relationships. In human beings Toxoplasma gondii cysts and Toxocara canis larvae infections are present in various anatomical sites including muscles, heart, lungs, eyes and brain. The presence of parasites in brain gives opportunity of manipulation of the host behavior. However, the mechanisms involved in the behavior changes are still unclear. The aims of this study were to assess changes in anxiety, fear, memory and learning, as well as the larvae, cysts and the presence of beta amyloid plaques (A) in the hippocampus region of the brain tissue of the Rattus norvegicus exper imentally infected with Toxocara canis and/or Toxoplasma gondii, in two stages of infection, satained with hematoxyl in/eosin (HE) and Red Congo techniques, respectively. Eighty female Rattus norvegicus species, aged six to eight weeks-old were used. The animals were divided into four groups: Toxocara - 10 rats infected with 300 Toxocara canis eggs, Toxoplasma - 10 rats infected with 10 cysts of Toxoplasma gondii, double infection - 10 mice infected with 300 Toxocara canis eggs and 10 Toxoplasma gondii cysts, and control - 10 rats without infection. In the days 40, 41, 70 and 71 after infection, the infected animals and that belonging to the control group were evaluated in the Elevated plus-maze (EPM) and Open- field (OF). At 120 days after infection the memory and learning evaluation and aversion to cat urine by the rats were assessed in the Barnes maze. At the end of the behavioral analysis the animals were euthanized to remove the brain and preparation of histological sect ions stained by Hematox yl in/Eosin (HE) and Congo Red. The results showed anxiolytic effect for both infections, especially for Toxoplasma gondii. There was no impairment of memory and learning in LB, but the animals infected by Toxocara canis or Toxoplasma gondii spentless time to find the bur row with urine and entering it. The reading of the histological sections stained with HE showed larvae of Toxocara canis and Toxoplasma gondii cysts in regions of the central nervous system of animals related to memory and learning. The slides stained with Congo Red showed A-plate for the majority of animals infected by Toxoplasma gondii. It is concluded in the single infection, to both parasites, produced anxiolytic effect. When infections occur concomitantly there was a modulating effect in rats\' behavior. In addition, rats infected with single infection presents less aversive urine cats.