Many organisms can acclimate to new environments through phenotypic plasticity, a complex trait that can be heritable, be subject to selection, and evolve. However, the rate and genetic basis of plasticity evolution remain largely unknown. Experimentally evolved populations of the nematode Caenorhabditis remanei were created by selecting for stress resistance under different environmental conditions. This resource was used to address key questions about how phenotypic plasticity evolves and what the genetic basis of plasticity is. Here, I highlight ways in which a fuller understanding of the environmental context influences our interpretation of the evolution of phenotypic plasticity. In a population selected to withstand heat stress, an apparent case of genetic assimilation did not show correlated changes in global gene regulation. However, further investigation revealed that the induced plasticity was not fixed across environments, but rather the threshold for the response was shifted over evolutionary time. Similarly, the past environment experienced by populations can play a role in directing the multivariate response to selection. Correlated responses to selection between traits and across environments were examined. The pattern of covariation in the evolutionary response among traits differed depending on the environment in which selection occurred, indicating that there exists variation in pleiotropy across the stress response network that is highly sensitive to the external environment. To understand how the patterns of pleiotropy are altered by environment and evolution, there is a pressing need to determine the structure of the molecular networks underlying plastic phenotypes. Using RNA-sequencing, the structure of the gene regulatory network is examined for a subset of evolved populations from one environment. Key modules within this network were identified that are strong candidates for the evolution of phenotypic plasticity in this system. Together, the data presented in this dissertation provide a comprehensive view of the myriad ways in which the environment shapes the genetic architecture of stress response phenotypes and directs the evolution of phenotypic plasticity. Additionally, the structure of transcriptional network provides valuable insight into the genetic basis of adaptation to environmental change and the evolution of phenotypic plasticity. This dissertation includes both previously published and co-authored material.

Dez vacas Gir foram adaptadas em tie-stall por 28 dias (Fase I/ pré-tratamento/ dias -28 a -1), sendo submetidas a duas sessões de OPU (dias -14 e -7). Na Fase II (tratamento/ dias 0 a 28) as mesmas foram divididas em Controle (GC/n=5) e Estresse (GE/n=5). O GC permaneceu em normotermia e o GE foi submetido a estresse calórico (EC) em câmara climática com temperatura e umidade controladas [38°C e 80% UR (DIA); 30°C e 80% UR (NOITE)], por 28 dias, procendendo-se, nesta fase, cinco OPU/fêmea. Na Fase III (pós-tratamento / dias 28 a 147) todas as fêmeas retornaram à normotermia (ambiente), sendo realizadas mais 17 OPU/fêmea. Diariamente foram registradas as temperaturas de bulbo seco (TBS) e úmido (TBU) e o índice de temperatura e umidade (ITU). As respostas fisiológicas avaliadas foram consumo de matéria seca (CMS), freqüência respiratória (FR), temperatura retal (TR), temperatura cutânea (TC), taxa de sudação (TS) e concentrações de cortisol e progesterona (P4). Fase luteínica foi definida como o período compreendido entre colheitas com P4 <1,0ng/mL. Semanalmente, com auxílio de um ultra-som (Scanner 200s) equipado com transdutor setorial intravaginal de 7,5MHz, foram aferidas a população folicular e o diâmetro dos dois maiores folículos. Em seguida, os folículos &ge;3mm foram puncionados e os oócitos recuperados foram avaliados morfologicamente, selecionados, maturados, fertilizados e cultivados in vitro. Os efeitos das variáveis classificatórias (animal, tratamento, fase e semana/sessão de OPU) sobre as variáveis resposta, e suas interações, foram analisadas por ANOVA para medidas repetidas no tempo (PROC MIXED do SAS®) e pelo teste de Qui-quadrado, com significância de 5%. Um animal foi excluído do GE após seis sessões, permanecendo somente quatro animais no GE e cinco no GC. O ITU durante o tratamento foi aumentado no GE em relação ao GC (93,1±0,15 vs. 73,6±0,5, respectivamente; P<0,05), acompanhado de uma elevação altamente significativa na FR, TR e TC (P<0,0001), caracterizando EC efetivo no grupo tratado. Na Fase II o GE apresentou CMS inferior ao GC (6,9±0,2 vs. 8,0±0,3, respectivamente; P<0,05). Nas fases pré e pós-estresse todas as variáveis climáticas e fisiológicas foram similares (P>0,05) entre tratamentos. Não houve efeito do EC na TS e nas concentrações de cortisol. O EC ocasionou longos períodos de aciclicidade (P4 <1ng/mL) e ciclos de curta duração (GE; 37,5% vs. GC; 8,6%; P<0,001). Houve efeito de sessão de OPU, mas não de tratamento no número de folículos visualizados e CCO\'s recuperados. Houve aumento no diâmetro folicular e codominância no GE. O percentual de CCO\'s selecionados para MIV e a taxa de clivagem não sofreram efeito do EC, contudo houve efeito imediato e tardio na taxa de produção de blastocistos, sendo de 35,5% no GE vs. 25,0% no CG (P=0,15) na fase II, e 27,2% vs. 13,3% (P<0,05) para os respectivos grupos, na fase III. De acordo com os dados aqui apresentados conclui-se que o EC em Bos indicus afetou negativamente a dinâmica ovariana, ocasionando falha no mecanismo de dominância folicular e diminuição na produção in vitro de embriões por um período superior a 105 dias. / Ten Gir (Bos indicus) cows were kept in tie-stalls for 28 days (Phase I/ before-trial/ days -28 to -1). Cows were submitted to two OPU sessions (days -14 and -7). In Phase II (trial/ days 0 to 28), cows were divided in Control (C/n=5) and Heat-stressed (HS/n=5). The CG remained in thermoneutral environment and the HS was kept under heat-stress in environmental chamber with controlled temperature and humidity [38°C and 80%UR (DAY), 30°C and 80%UR (NIGHT)], for 28 days. During this phase five OPU sessions were accomplished. In Phase III (post-trial/ days 28 to 147) all cows returned to thermoneutral environmental temperatures and 17 OPU sessions were performed. The dry (DBT) and humid (HBT) bulb temperatures were daily measured and obtained the temperature-humidity index (THI). Physiological responses as dry matter intake (DMI), respiratory frequency (RF), rectal temperature (RT), skin temperature (ST), sweating rate (SR), plasma cortisol and progesterone (P4) were assessed. Luteal phase was defined as the period between two samples with P4 below 1.0ng/mL. Once a week, prior to OPU procedure, the number of follicles in the ovary and the diameter of the two biggest follicles were evaluated using an ultrasound (Scanner 200s, 7.5MHz sectorial probe). Subsequently, all follicles &ge;3mm were aspirated and the oocytes morphologically evaluated, selected, maturated, fertilized and cultivated for embryo production in vitro. The effects of independent variables (cow, treatment, phase, and week/OPU session) on the dependent variables were analyzed by ANOVA for repeated measures (PROC MIXED of SAS®) and by Chi-square test, both with a significance level of 5%. One animal was excluded from HS after sixth session, having remained four vs. five cows for CG and HS groups respectively. The THI increased during heat-stress treatment (93.1 ± 0.15 vs. 73.6 ± 0.5 for HS and CG respectively, P<0.05), simultaneously to a significant increase in RF, RT and ST (P<0.0001). It was characterized as effective heat-stress on the treated cows. In phase II the HS showed lower DMI than CG (6.9±0.2 vs. 8.0±0.3 respectively, P<0.05). All environmental and physiologic variables were similar (P>0.05) between treatments in the periods before and post heat-stress. There was no effect of heat-stress on SR and cortisol levels. The HS treatment induced to longer periods of ovarian inactivity (P4 <1ng/mL) as well as short cycles (HS, 37.5% vs. CG, 8.6%, P<0.001). There was effect of OPU session but not of treatment on number of visualized follicles or recovered oocytes. The diameter of the biggest follicles and incidence of codominance increased in HS treatment (P<0.05). Moreover, there was no effect of heat-stress on percentage of COCs selected to IVF or cleaved. However, immediate and delayed effects were observed on blastocists yield (35.5% vs. 25.0%, P=0.15, for CG and HS groups on the phase II and 27.2% vs. 13.3%, P<0.05, for respective groups on the phase III). Our results suggest that the ovarian dynamics of Bos indicus cattle was affected by heat-stress exposure, showing failures on follicular dominance and on in vitro embryos yield for at least 105 days after the heat-stress subside.

Uma série de fatores como ambiente, nutrição e doenças podem ser consideradas como estressores em sistemas de produção. Frangos de corte expostos a estressores por períodos prolongados de tempo apresentam de forma geral, redução do ganho de peso e consumo de ração, aumento da conversão alimentar, aumento da média de mortalidade e predisposição a doenças. A vacinação é uma prática essencial para um adequado manejo da produção e o desenvolvimento da imunidade do frango de corte frente a desafios bacterianos e virais presentes no ambiente. O entendimento dos fatores que podem interferir com o sucesso da vacinação é essencial para a otimização da saúde e do bem-estar animal, permitindo a utilização de todo o seu potencial genético e nutricional. Poucos estudos têm enfatizado o efeito do estresse por calor na imunidade celular e humoral de frangos de corte. Este trabalho tem como objetivo estudar o efeito do estresse por calor sobre a imunidade celular (linfócitos B e T), humoral sérica (IgM e IgY) e o peso relativo de órgãos (baço, bursa e fígado) de frangos de corte submetidos a um protocolo de vacinação para a Doença de Newcastle (cepa LaSota). Para tanto, 96 frangos de corte Cobb machos foram aleatoriamente divididos em quarto grupos: grupo 1. Frangos de corte não vacinados expostos à temperatura termoneutra; grupo 2. Frangos de corte vacinados expostos à temperatura termoneutra; grupo 3. Frangos de corte não vacinados expostos ao protocolo de estresse térmico por calor (38±2°C); e grupo 4. Frangos de corte vacinados expostos ao protocolo de estresse térmico por calor (38±2°C). Todas as aves foram alojadas em isoladores com água e ração ad libitum. Foi utilizada uma vacina com o vírus atenuado para Doença de Newcastle (cepa LaSota) administrada em duas doses, aos 7 e aos 14 dias de vida. Os frangos submetidos ao protocolo de estresse foram expostos a uma temperatura de (38±2°C) do segundo até o sexto dia de vida. Os dados obtidos demonstraram que o estresse por calor de forma isolada reduziu o peso relativo do fígado e aumenta aquela do baço e da bursa e induziu uma alteração significativa do perfil de células imunes no sangue periférico das aves, como consequência, observou-se alteração no padrão de imunoglobulinas, o que influenciou diretamente a resposta da ave frente ao desafio ambiental (quando o estresse foi avaliado isoladamente) ou vacinal (quando o estresse foi avaliado juntamente ao desafio vacinal com o vírus da Doença de Newcastle). Dessa forma, sugerimos que o estresse por calor diminuiu a eficácia da resposta vacinal aos frangos de corte, em função de mudanças que induziu no perfil de linfócitos e produção de imunoglobulinas. / A number of factors, such as environment, nutritional status and diseases are stressful for animals during livestock production. It has been shown that broilers exposed to stressors for prolonged periods tend to present decreased weight gain and feed intake and to have an increased feed conversion ratio, increase mortality rate and predisposition to diseases caused by secondary agents. Vaccination is an essential practice for adequate management of the livestock and protection of poultry against bacterial and viral infectious agents. Understanding the factors that modify the success vaccination is essential for optimizing animal health and welfare, thus allowing them to use of all the genetic and nutritional potential they have. Few studies have emphasized the effects of heat stress on cellular and humoral broilers immunity. This study aimed at discussing the effects of heat stress on cellular immunity (B and T lymphocytes) and humoral immunity (IgM and IgY) of broilers undergoing a vaccination protocol for Newcastle disease (LaSota strain). For this purpose, 96 male broilers (Cobb) were random divided into four groups: 1. Unvaccinated broiler chickens exposed to thermoneutral temperature; 2. Vaccinated broiler chickens exposed to thermoneutral temperature; 3. Unvaccinated broiler chickens exposed to a heat stress protocol (38±2°C). 4. Vaccinated broiler chickens exposed to a heat stress protocol (38±2°C). All broilers were housed in isolators and provided water ad lib. We used a live Newcastle vaccine disease virus of LaSota strain given in two doses at 7 and 14 days. The broiler chickens were exposed to heat stress (38±2°C) from the 2nd to 6th day of life. It has been observed that when combined with the vaccination challenge, heat stress was able to change immune cells profile from a B to T cytotoxic and T helper immune cells, keeping this change pattern until the end of the study period (over 19 days). This change in the cellular response pattern modified the ability of the broiler chickens´ immune system to react while challenged by vaccination, reducing its efficiency and making them more susceptible to the disease agent. The data obtained suggest that heat stress by itself induced considerable modifications in the liver, spleen and bursa de Fabricius and induced a significant modification in the profile of immune cells in peripheral blood of birds, with responsive modifications in the pattern of immunoglobulins, directly influencing the response of the broilers against the environmental challenge (when the stress is evaluated separately) or the vaccination (when the stress is measured along the challenge vaccination with Newcastle Disease virus). Therefore, we suggest that the heat stress was capable of reduce the efficacy of the vaccinal response in broiler chickens, related to the modification of the lymphocytes and the production of immunoglobulins.

Os conceitos de bem-estar animal são uma realidade dentro da avicultura mundial. Sabe-se que aves estressadas apresentam diminuição no crescimento e na conversão alimentar, desajustes fisiológicos e hormonais, bem como aumento da suscetibilidade a doenças em decorrência de modificações induzidas pelo estresse na resposta imune. Além disso, eventos estressantes vêm sendo relacionados com distúrbios na integridade da microbiota intestinal. Nesse sentido, buscamos neste trabalho estudar os efeitos do estresse térmico por calor nas temperaturas de 26±1ºC, 31±1ºC e 36±1ºC sobre os índices zootécnicos, a integridade intestinal e a imunidade inata de frangos de corte, correlacionado e discutindo os achados experimentais dentro de uma perspectiva neuroimune. Nossos resultados mostraram que o estresse por calor (31±1ºC e 36±1ºC) em frangos de corte: (1) diminuiu o ganho de peso e o consumo de ração, porém só observamos diminuição da conversão alimentar e da mortalidade nas aves submetidas ao estresse de 36±1ºC; (2) diminuiu o peso relativo da bursa de Fabrícius, porém apenas a temperatura de 36±1ºC diminuiu o peso relativo do timo; (3) diminuiu o burst oxidativo basal de macrófagos, porém apenas a temperatura de 31±1ºC foi capaz de diminuir o burst oxidativo dessa célula na presença de S. aureus. (4) aumentou os níveis séricos de corticosterona; e (5) observamos presença de discreta enterite caracterizada por aumento de infiltrado inflamatório linfo-plasmocitario na lamina própria do jejuno. Tomados em seu conjunto, os presentes dados permitem afirmar que o estresse térmico por calor tenha produzido alterações na atividade neuroimune dos frangos de corte modificando, nos mesmos a atividade do eixo HPA; essas alterações teriam influenciado o desempenho produtivo e a imunidade, propiciado do aparecimento de processos inflamatórios intestinais. / The concept of animal welfare is a reality in the world poultry industry. Stressed chickens present a decrease in growth performance and feed conversion, physiological and hormonal changes as well as an increased susceptibility to diseases. Recurrent changes induced by in stress in human and animals immune functions were also reported after stress in poultry. Besides that, stressed events were reported to be related to intestinal microbiota integrity disturbances. In this sense, we evaluated the effects of heat stress (26±1ºC, 31±1ºC and 36±1ºC) on broiler chickens performance parameters, intestinal morphology and innate immunity, correlating and discussing the observed data under a neuroimmune perspective. Ours results showed the heat stress (31±1ºC and 36±1ºC) in broiler chickens (1) decreased body weight gain and feed consumption, however feed conversion and mortality decreased only in chickens submitted to 36±1ºC, (2) decreased the bursa of Fabricius relative weight in 31±1ºC and 36±1ºC, but thymus relative weight decreased only in the 36±1ºC stressed chickens, (3) decreased macrophage basal oxidative burst, however only the 31±1ºC heat stress decreased S. aureus induced oxidative burst, (4) increased corticosterona serum levels, and (5) induced an enteritis characterized by increased presence of lymphocytes and plasmocytes within the lamina propria of jejunum. These obtained results suggested that heat stress-induced changes in broiler chickens were a consequence of a neuroimune activity disturbance, most probably, on animals HPA axis activity. Thus, a possible increase in corticosterona serum levels induced by the heat stress underlay the effects of this stressor on birds\' performance and immune function, leading to the appearance of intestinal histophatological signs of inflammation.

Upon exposure to heat or cold, Arabidopsis thaliana seedlings undergo rapid transcriptional reprogramming of several hundreds of genes that promote stress tolerance. Despite extensive characterisation of the transcriptional responses to these stimuli, however, relatively little is known about the mechanisms by which temperature signals are perceived and transduced in plant cells. High or low seasonal temperatures have large impacts on crop productivity and are expected to intensify given current global climatic projections. It is therefore of agricultural importance to better understand temperature signalling pathways in plants in order to find solutions to this problem. In this thesis, a chemical genomics screen for molecules activating or repressing heat-inducible genes in A. thaliana was performed in collaboration with Syngenta and the biological targets of these chemicals were predicted based on structural similarities to compounds with known modes of action. Many molecules that affect the function of chloroplasts or mitochondria either activate or repress heat-responsive genes, thus implicating these organelles in the regulation of plant temperature responses. In addition, the translation inhibitor cycloheximide was identified as a repressor of heat-inducible genes and an activator of early cold-inducible genes. Diverse translation inhibitors trigger a cytosolic influx of calcium ions and several inhibitors of translation elongation were found to strongly activate cold-inducible gene expression in a calcium-dependent manner. Furthermore, it was demonstrated that cold shock causes rapid translation repression in A. thaliana seedlings and that the elongation factor LOS1 is involved in cold- or cycloheximide-induced gene expression, thus implicating translational machinery in the regulation of temperature signalling in plants. Finally, one of the chemicals identified in the screen, S01A463859Y, was found to improve heat resilience in A. thaliana and may therefore be of potential use in enhancing crop productivity during thermal stress.

Uma série de fatores como ambiente, nutrição e doenças podem ser consideradas como estressores em sistemas de produção. Frangos de corte expostos a estressores por períodos prolongados de tempo apresentam de forma geral, redução do ganho de peso e consumo de ração, aumento da conversão alimentar, aumento da média de mortalidade e predisposição a doenças. A vacinação é uma prática essencial para um adequado manejo da produção e o desenvolvimento da imunidade do frango de corte frente a desafios bacterianos e virais presentes no ambiente. O entendimento dos fatores que podem interferir com o sucesso da vacinação é essencial para a otimização da saúde e do bem-estar animal, permitindo a utilização de todo o seu potencial genético e nutricional. Poucos estudos têm enfatizado o efeito do estresse por calor na imunidade celular e humoral de frangos de corte. Este trabalho tem como objetivo estudar o efeito do estresse por calor sobre a imunidade celular (linfócitos B e T), humoral sérica (IgM e IgY) e o peso relativo de órgãos (baço, bursa e fígado) de frangos de corte submetidos a um protocolo de vacinação para a Doença de Newcastle (cepa LaSota). Para tanto, 96 frangos de corte Cobb machos foram aleatoriamente divididos em quarto grupos: grupo 1. Frangos de corte não vacinados expostos à temperatura termoneutra; grupo 2. Frangos de corte vacinados expostos à temperatura termoneutra; grupo 3. Frangos de corte não vacinados expostos ao protocolo de estresse térmico por calor (38±2°C); e grupo 4. Frangos de corte vacinados expostos ao protocolo de estresse térmico por calor (38±2°C). Todas as aves foram alojadas em isoladores com água e ração ad libitum. Foi utilizada uma vacina com o vírus atenuado para Doença de Newcastle (cepa LaSota) administrada em duas doses, aos 7 e aos 14 dias de vida. Os frangos submetidos ao protocolo de estresse foram expostos a uma temperatura de (38±2°C) do segundo até o sexto dia de vida. Os dados obtidos demonstraram que o estresse por calor de forma isolada reduziu o peso relativo do fígado e aumenta aquela do baço e da bursa e induziu uma alteração significativa do perfil de células imunes no sangue periférico das aves, como consequência, observou-se alteração no padrão de imunoglobulinas, o que influenciou diretamente a resposta da ave frente ao desafio ambiental (quando o estresse foi avaliado isoladamente) ou vacinal (quando o estresse foi avaliado juntamente ao desafio vacinal com o vírus da Doença de Newcastle). Dessa forma, sugerimos que o estresse por calor diminuiu a eficácia da resposta vacinal aos frangos de corte, em função de mudanças que induziu no perfil de linfócitos e produção de imunoglobulinas. / A number of factors, such as environment, nutritional status and diseases are stressful for animals during livestock production. It has been shown that broilers exposed to stressors for prolonged periods tend to present decreased weight gain and feed intake and to have an increased feed conversion ratio, increase mortality rate and predisposition to diseases caused by secondary agents. Vaccination is an essential practice for adequate management of the livestock and protection of poultry against bacterial and viral infectious agents. Understanding the factors that modify the success vaccination is essential for optimizing animal health and welfare, thus allowing them to use of all the genetic and nutritional potential they have. Few studies have emphasized the effects of heat stress on cellular and humoral broilers immunity. This study aimed at discussing the effects of heat stress on cellular immunity (B and T lymphocytes) and humoral immunity (IgM and IgY) of broilers undergoing a vaccination protocol for Newcastle disease (LaSota strain). For this purpose, 96 male broilers (Cobb) were random divided into four groups: 1. Unvaccinated broiler chickens exposed to thermoneutral temperature; 2. Vaccinated broiler chickens exposed to thermoneutral temperature; 3. Unvaccinated broiler chickens exposed to a heat stress protocol (38±2°C). 4. Vaccinated broiler chickens exposed to a heat stress protocol (38±2°C). All broilers were housed in isolators and provided water ad lib. We used a live Newcastle vaccine disease virus of LaSota strain given in two doses at 7 and 14 days. The broiler chickens were exposed to heat stress (38±2°C) from the 2nd to 6th day of life. It has been observed that when combined with the vaccination challenge, heat stress was able to change immune cells profile from a B to T cytotoxic and T helper immune cells, keeping this change pattern until the end of the study period (over 19 days). This change in the cellular response pattern modified the ability of the broiler chickens´ immune system to react while challenged by vaccination, reducing its efficiency and making them more susceptible to the disease agent. The data obtained suggest that heat stress by itself induced considerable modifications in the liver, spleen and bursa de Fabricius and induced a significant modification in the profile of immune cells in peripheral blood of birds, with responsive modifications in the pattern of immunoglobulins, directly influencing the response of the broilers against the environmental challenge (when the stress is evaluated separately) or the vaccination (when the stress is measured along the challenge vaccination with Newcastle Disease virus). Therefore, we suggest that the heat stress was capable of reduce the efficacy of the vaccinal response in broiler chickens, related to the modification of the lymphocytes and the production of immunoglobulins.

O objetivou-se com este trabalho foi avaliar a influência de óleos funcionais e monensina na dieta de vacas no verão sobre o consumo de matéria seca, parâmetros produtivos, sanguíneos, fisiológicos e hormonais, fermentação ruminal e a digestibilidade aparente total dos nutrientes. O projeto foi conduzido no Centro de Análise e Pesquisa Tecnológica do Agronegócio (APTA), no setor de Bovinos de Leite, Instituto de Zootecnia, Nova Odessa, SP. Foram utilizadas oito vacas da raça Holandesa primíparas, lactantes (68 ± 3,46 dias de lactação e 511,56 ± 65,38 pesos vivos), distribuídas em dois quadrados latinos contemporâneos, em arranjo fatorial 2x2, ou seja, dieta sem inclusão de aditivo, dieta com inclusão de óleo funcional (OF, 0,5 g/kg MS), dieta com inclusão de monensina (MO, 30 mg/kg MS) e dieta com inclusão de óleo funcional e monensina, nas mesmas quantidades já descritas. As vacas foram mantidas a temperatura média de 25,31°C ± 0,26; umidade relativa do ar de 71,24% ± 1,03 e índice de temperatura e umidade de 73,85 ± 0,14. No presente experimento não observou interação entre os tratamentos, porém os animais com OF apresentaram maior CMS e a inclusão de MO diminuiu esse parâmetro. Se tratando dos parâmetros fermentativos, a inclusão de MO aumentou a concentração de propionato e isovalérico, consecutivamente sua proporção e diminuiu a relação acético: propiônico, OF não alterou a fermentação ruminal. Os parâmetros bioquímicos apresentaram interação na quantidade de ácidos graxos não esterificados (NEFA), sendo que, a não inclusão de aditivos foi maior sua concentração do que a inclusão de ambos os aditivos. Quando se tratando da digestibilidade dos nutrientes, não houve diferença significativa para nenhuma das frações. Para aos parâmetros produtivos, a produção de leite, produção de leite corrigida para 3,5% de gordura e quantidade de gordura ocorreu interação entre os tratamentos, onde a dieta com OF na ausência de monensina aumentou esses parâmetros e quando incluído MO diminuiu. Já dieta com somente MO funcional diminuiu, os mesmos parâmetros, e a presença dos dois aditivos aumentou. A quantidade de lactose, proteína e o teor de proteína foram maiores para o tratamento incluído OF. A inclusão de MO diminuiu os teores de gordura e sólidos totais, porém esse tratamento apresentou maior eficiência produtiva. Nos parâmetros fisiológicos a quantidade de tiroxina (T4), e frequência respiratória (FR) também foi maior quando incluído OF comparado sem inclusão de aditivos. Já os demais parâmetros fisiológicos e hormonais (temperatura retal e do pelame e triiodotironina, T3) não foram afetados. O óleo funcional demonstrou eficácia em melhorar a produção de leite e consumo em animais submetidos a estresse calórico crônico sem alterar a fermentação ruminal e digestibilidade, porém aumentou a FR e o T4. Entretanto, a monensina foi capaz de alterar a fermentação sem alterar o consumo e os parâmetros fisiológicos e hormonais, também sendo mais eficiente produtivamente. / The objective of this work was to evaluate the influence of functional oils and monensin in the diet of cows submitted in the summer on dry matter intake, and how this influence affected their blood as well as their productive, physiological and hormonal parameters, ruminal fermentation and apparent digestibility of feed. The project was conducted in the Milk Cattle Sector at the Agribusiness Technological Research and Analysis Center (APTA), Institute of Animal Science, Nova Odessa, SP. Eight primiparous, lactating Holstein cows (68 ± 3.46 days of lactation and 511.56 ± 65.38 live weights) were used and distributed in two contemporary Latin squares, in a 2x2 factorial arrangement. They received four diets one without the inclusion of additives, one with functional oil (OF, 0.5 g / kg DM), one with monensin (MO, 30 mg / kg DM), and one with both functional oil and monensin with the same quantities as described. The cows were submitted to a mean temperature of 25.31°C ± 0.26 with a relative humidity of 71.24% ± 1.03 and a temperature and humidity index of 73.85 ± 0.14. In the present experiment, there was no interaction between the treatments, but the animals with + OF presented higher CMS and + MO decrease this parameter. When treating the fermentation parameters with MO, there was an increase in the amount of propionate and isovaleric, however, a decrease in the acetic: propionic ratio occurred. At the same time, only the proportion of propionate increased when treated with MO while isovaleric and acetic proportions remained the same, and the inclusion of OF did not alter the ruminal fermentation. The biochemical parameters showed interaction in the amount of non-esterified fatty acids (NEFA), and the without additives the concentration of NEFA was higher than with the inclusion of both additives. When it came to nutrient digestibility, there was no significant difference for any of the fractions. Regarding the productive parameters concerning milk production, this adjusted to 3.5% fat and the amount of fat experienced interaction between treatments of OF and MO; the diet with OF in the absence of monensin saw an increase in these productive parameters and when MO was included, a decrease occurred. The diet with only functional MO saw a decrease in the productive parameters, while this increased in the presence of both additives. The amount of lactose, protein, and protein content were higher in the treatments including OF. The inclusion of MO decreased the total fat and solid contents, but this treatment presented a higher productive efficiency. In the physiologic parameters the thyroxin (T4). The respiratory rate (RR) was also higher when including OF in comparison without additives, while the other physiological and hormonal parameters (rectal temperature, skin and triiodothyronine, T3) were not affected. Functional oil showed efficacy in improving milk production and consumption in animals submitted to chronic caloric stress without altering rumen fermentation and digestibility, but increased RF and T4. However, monensin was able to alter the fermentation without altering the consumption and the physiological and hormonal parameters, also being more efficient productively.

Les écosystèmes marins constituent une cible majeure des changements globaux qui affectent de façon pérenne notre planète.Nous nous sommes intéressés à deux de ces changements susceptibles de menacer le milieu marin : le réchauffement climatique par le biais de l’étude de l’effet du stress thermique sur l’expression de ho-1 et la pollution via l’étude de l’impact des métaux lourds à effets perturbateurs endocriniens (le cadmium et le plomb) sur l’axe hypothalamo-hypophyso-gonado-hépatique (HHGH) chez le loup (Dicentrarchus labrax L.).Nos résultats montrent une réponse importante de ho-1 aux stress thermique et chimique dans le foie. Nous avons également démontré une forte accumulation hépatique du Cd, et à un degré moindre du Pb, accompagnée d’une sur-expression du gène mt codant pour les métallothionéines. Des variations dans l’expression de gènes clés le long de l’axe HHGH (arom b, fshß, arom a…) ont été observées après intoxication par les deux métaux sans pour autant induire des effets physiologiques observables.La question se pose de savoir si la synergie des stress physico-chimiques impacte la dynamique et l’état sanitaire des populations marines. / Marine ecosystems are a major target of global changes that continuously affect our planet. In the present study we investigated two of these changes that may threaten the marine environment: global warming, through the study of the effect of heat stress on ho-1 expression and marine pollution through the study of the impact of heavy metals acting as endocrine disruptors (cadmium and lead) on the hypothalamic-pituitary-gonadal-liver (HHGL) axis in the sea bass (Dicentrarchus labrax L.). Our results show an important response of ho-1 to both thermal and chemical stress in the liver. We also demonstrated a high hepatic accumulation of Cd, and to a lesser extent of Pb. This accumulation was correlated with an overexpression of mt gene coding for metallothionein. Changes in the expression of candidate genes (arom b, fshß, arom a…) along the HHGL axis were observed after metal intoxication but no physiological effects were observed.The question then arises to what extent the synergy of physicochemical stressors impacts the dynamics and the welfare of marine species.

The human central nervous system (CNS) is capable of significant architectural and physiological reorganization in response to environmental stimuli. Novel sensorimotor experiences stimulate neuronal networks to modify their intrinsic excitability and spatial connectivity within and between CNS structures. Early learning-induced adaptations in the primary motor cortex are thought to serve as a priming stimulus for long term CNS reorganization underlying long-lasting changes in motor skill. Recent animal and human studies suggest that whole body exercise and core temperature elevation as systemic stressors also recruit activity-dependent processes that prime the motor cortex, cerebellum, and hippocampus to process sensorimotor stimuli from the environment, enhancing overall CNS learning and performance. A primary goal of rehabilitation specialists is to evaluate and design activity-based intervention strategies that induce or enhance beneficial neuroplastic processes across the lifespan. As such, an investgation of the influence of physical, non-pharmacological interventions on cortical excitability, motor learning, and cognitive function provide the central theme of this dissertation. The first study investigated the effects of a visually-guided motor learning task on motor cortex excitability at rest and during voluntary activation measured via transcranical magnetic stimulation (TMS). Motor learning significantly increased resting cortical excitability that was not accompanied by changes in excitability as a function of voluntary muscle activation. The cortical silent period, a measure of inhibition, increased after learning and was associated with the magnitude of learning at low activation. These findings suggest that separate excitatory and inhibitory mechanisms may influence motor output as a function of learning success. The following studies investigated the influence of systemic whole-body thermal stress on motor cortex excitability, motor learning and cognitive performance. We established the reliability of a novel TMS cortical mapping procedure to study neurophysiological responses after whole-body heat stress. Heat stress significantly potentiated motor cortex excitability, though acute motor learning and cognitive test performance did not differ between subjects receiving heat stress and control subjects. Future research is needed to delineate the potential of whole body heat stress as a therapeutic modality to influence central nervous system plasticity and performance.

Heat stress is a well documented hazard across industries. The combination of environmental conditions, work demands, and clothing contribute to heat strain. Left unchecked, heat strain causes changes in an individual's physiological state that can lead to serious and fatal conditions with little warning. Although engineering and administrative controls are the first choice to abate this hazard, they frequently are not feasible. In these cases, personal cooling is often employed. There are three main types of personal cooling: liquid, air, and passive. Each has its own advantages and disadvantages. This study focuses on continuous cooling using a portable liquid cooling system (LCS). The LCS used a vest with tubes circulating water from an ice heat sink. The experiment consisted of five males each completing seven tests in random order. The subjects wore work clothes as the control then in conjunction with a firefighter, vapor barrier, and bomb suits. Each suit was tested with and without the benefit of the LCS. All of the tests took place at 35oC dry bulb and 50% relative humidity while attempting to walk 90 minutes on a treadmill at a 300 W metabolic rate. The study found continuous use of the LCS significantly reduced heat storage (S) and the rate of rise of heart rate (rrHR), core temperature (rrTre), and mean skin temperature (rrTsk) for the firefighter and vapor barrier suits as compared to no-cooling. Although the LCS didn't significantly affect the rate of rise for physiological responses with the bomb suit, it did however, significantly increase the endurance time. Interestingly, the study also found when wearing either the vapor barrier or firefighter suits in conjunction with the LCS that the rrHR and rrTre were not significantly different from only wearing work clothes.