• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1106
  • 411
  • 167
  • 124
  • 124
  • 93
  • 42
  • 41
  • 37
  • 34
  • 23
  • 18
  • 17
  • 15
  • 11
  • Tagged with
  • 2747
  • 430
  • 246
  • 224
  • 211
  • 194
  • 165
  • 152
  • 145
  • 140
  • 135
  • 132
  • 130
  • 122
  • 120
  • 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.
1251

Základní příjem perspektivou multiagentního modelování / The Basic Income concept in the perspective of Agent-Based modelling

Macháček, Vít January 2016 (has links)
The Basic Income concept in the perspective of Agent-Based modelling Abstract: The thesis study the relationship between the basic income introduction and the price level. The basic income would replace the existing social security. The resulting redistribution induce changes in the aggregate demand through the concave consumption function. The aggregate demand in turn affect the price creation mechanism. Because the price level is a result of activity of many different agents with private motivation and information, the work used a simple macroeconomic agent-based model to isolate the relationship. The simulation however did not succeed in isolating the possible link between the price level and the basic income introduction.
1252

Analýza zavedení "šrotovného" z pohledu udržitelného rozvoje / Analysis of the implementation of scrapping scheme from the perspective of sustainable development

Balounová, Veronika January 2010 (has links)
The theme of the thesis is scrapping scheme, which was in the Czech Republic during years 2009 and 2010 very discussed and that was despite government meetings stretching over a year finally unloaded. The work collect a large amount of information about scrapping schemes, a state contribution on the disposal of car wrecks, mainly about its implementation in several countries, the subsequent tract and analysis of resulting impacts. Based on experience from other countries with an already undertaken scrapping programs are identified potential impacts that could have a scrapping scheme in the case of implementation in the Czech Republic in the future. The work is also examining the effectiveness of Czech government finance earmarked for scrapping scheme. The main goal of the thesis is to answer the question whether the implementation of scrapping scheme in the Czech Republic would be an appropriate anti-crisis tool.
1253

Vliv tělesné kondice dojnic na hladinu ketolátek v krvi

BEŇASOVÁ, Veronika January 2019 (has links)
The aim of this diploma thesis is to evaluate the data about holstein dairy cow body condition at calving and to review its effect on ketones blood level and its relation to incidence of ketosis. The monitoring took place in a selected dairy farm from October 2017 to February 2019. Body condition of 280 cows was evaluated on the day of calving by assessing the body condition score (BCS) and later on 10 days in milk the blood level of B-hydroxybutyrate was measured. Furthermore, parity, body weight in calving day, body weight on 10 days in milk, content of milk fat and protein on 10 days in milk and milk yield on 10 days in milk were monitored. Average BCS of the herd was 3,7, the maximum measured BCS value was 5, the minimum was 2. Total incidence of ketosis on herd level was 21,07 % considering ketosis if BHB 1,0 mmol.l-1. 62,7 % of that was a subclinical form of ketosis while the remaining 37,3 % was the clinical form of ketosis. Correlation analysis of the relation between parity and level of BHB in blood showed positive correlation (r=0,15, p=0,00), when cows on higher lactation had higher level of blood BHB. Positive correlation between fat/protein ratio in milk and level of BHB in blood was evaluated by correlation analysis (r=0,31 , p=0,00). The BCS at calving and BHB level on 10 days in milk showed positive correlation (r=0,14 , p=0,02). As far as negative energy balance is taken into account, the positive correlation between BCS at calving and body weight loss was confirmed (r=0,17 , p=0,00). The fact that heavier cows and cows with higher BCS mobilise more body fat reserves was confirmed by positive correlation between the body weight at calving and the body weight loss (r=0,47, p=0,00) and between the body weight at calving and the fat/protein ratio in milk (r=0,27, p=0,00). Body weight at calving had provable positive impact on the milk yield (r=0,19, p=0,00).
1254

[en] PRINCIPAL COMPONENT ANALISYS AND NEURAL NETWORK APPROACHES TO THERMAL EXPANSION OF CERAMICS OXIDES / [pt] ANÁLISE DA EXPANSÃO TÉRMICA DE ÓXIDOS CERÂMICOS UTILIZANDO AS ABORDAGENS DE ANÁLISE DE COMPONENTES PRINCIPAIS E REDES NEURAIS

ADALVARO GARCIA ROSA 04 November 2013 (has links)
[pt] Alguns óxidos cerâmicos apresentam Coeficiente de Expansão Térmica Negativa (ETN). Estes materiais usados como compósitos podem controlar a expansão térmica em valores determinados, inclusive zero. Este trabalho tem como objetivo propor novos óxidos da família A2M3O12 com coeficiente de expansão próximo a zero. Foi usada a Análise de Componentes Principais (PCA) para se verificar estatisticamente a causa de ETN em 45 óxidos conhecidos desta família e a partir daí foi usada uma Rede Neural para simulação de novos óxidos. / [en] Some ceramic oxides exhibit negative coefficient of thermal expansion. These material generally used as compounds can control the thermal expansion in determined values, including zero. The aim of this work is to propose new oxides of the family type A2M3O12 with coefficient of thermal expansion close to zero. The Principal Component Analysis (PCA) is used to statistically verify the reason for negative thermal expansion in 45 known oxides of this family and then, the neural network approach is used for simulation of new oxides.
1255

HIV and Pre-eclampsia: Is there a connection?:

Frank, Karlyn Annesa 23 February 2007 (has links)
Student Number : 9402058P - M Med Research Report - School of Clinical Medicine - Faculty of Health Sciences / Objective In view of recent suggestions that HIV infection may protect against pre-eclampsia, this study was done to estimate whether untreated HIV positive pregnant women have a lower rate of preeclampsia-eclampsia than HIV negative women. Methods Subjects for this study were pregnant women from Soweto, South Africa, who gave birth from March to December 2002 at midwife-run clinics or at the Chris Hani Baragwanath Hospital, and in whom the HIV status was known. A sample size calculation indicated that 2588 subjects would be required to show statistical significance at P<0.05 with a power of 80% for a reduction in the rate of preeclampsia from 8% to 5% with HIV seropositivity, assuming an HIV seroprevalence rate of 30%. Data collection was by record review from randomly selected patient files and birth registers. Results In the total sample of 2600 women, 1797 gave birth at the hospital and 803 at the midwife-run clinics. The HIV seroprevalence rate was 27.1%. Hypertension was found in 17.3% of women, with 5.3% having preeclampsia-eclampsia. The rates of preeclampsia-eclampsia were 5.2% in HIV negative and 5.7% in HIV positive women (P=0.61). CD4 count results were available for only 13 women (0.5%). Conclusion HIV seropositivity was not associated with any reduction in the risk of developing preeclampsia-eclampsia.
1256

La haine envers la marque : conceptualisation, mesure et conséquences / Brand hate : conceptualization, measurement and consequences

Bottin, Amélie 12 December 2016 (has links)
Ce travail doctoral concerne la haine envers la marque ressentie par les consommateurs. Présentée dans cette recherche comme impliquant une attitude globale négative envers une marque, elle est composée de plusieurs émotions négatives et engendre toujours un comportement. A partir de trois recherches exploratoires et de quatre recherches quantitatives, (1) nous définissons le concept en cinq dimensions ; (2) nous mettons en évidence l’attitude négative envers la marque en tant qu’antécédent de la haine envers la marque et de ses dimensions, ainsi que le bouche-à-oreille négatif et l’évitement de la marque comme leurs conséquences ; (3) nous identifions les variables modératrices de ces relations que sont le locus de contrôle, la réactance psychologique, l’estime de soi et la propension du consommateur à résister ; et enfin (4) nous dressons quatre profils des consommateurs haineux à partir des dimensions de la haine envers la marque et des données socio-démographiques / This doctoral paper deals with brand hate related by consumers. Presented in this research as involving an overall negative attitude toward a brand, it is composed of several negative emotions, and always generates a behavior. From three exploratory and four quantitative studies, (1) we define the concept in five dimensions; (2) we highlight the negative attitude toward the brand as brand hate and its dimensions antecedent and negative word-of-mouth and the avoidance of the brand as their consequences; (3) we identify the moderator variables of these relationships as the locus of control, psychological reactance, self-esteem and propensity of consumer to resist; and (4) we draw four hate consumers profiles from the dimensions of brand hate and sociodemographic data
1257

Qualidade microbiológica do ar no centro de material e esterilização: avaliação do impacto da pressão negativa na área da limpeza / Microbiological quality of air in the Material and Sterilization Center: evaluation of the impact of negative pressure in the cleaning area

Almeida, Alda Graciele Claudio dos Santos 07 August 2018 (has links)
Introdução: Recomendações nacionais (RDC ANVISA 15/2012; 50/2002) e internacionais determinam que as áreas destinadas à limpeza dos produtos para saúde (PPS) no Centro de Material e Esterilização (CME) mantenham um diferencial de pressão negativo do ar ambiente (BRASIL, 2012; AAMI, 2006; ASHARE, 2013). Entretanto, essa recomendação, até o momento, não está sustentada por estudos de alto rigor científico. Embora não houvessem justificativas explicitadas para tal recomendação, presume-se que seja prioritariamente pelo risco de transferência aérea de microrganismos, da área de limpeza para as áreas adjacentes, configurando-se em risco ocupacional. Objetivo: Avaliar o impacto da presença da pressão negativa na área de limpeza do CME mediante a avaliação da qualidade microbiológica do ar desse setor e da área de preparo dos PPS. Método: Foram comparadas amostras microbiológicas do ar coletadas da sala de limpeza (área suja) e da sala de preparo (área limpa) de dois CME classe II de um mesmo hospital localizado na cidade de São Paulo: com e sem sistema de pressão negativa do ar na área de limpeza, este último com sistema de condicionamento do ar centralizado. Como controle, foram realizadas coletas do ar exterior ao hospital. Para obter amostras microbiológicas, foi utilizado o amostrador air six-stage Andersen, com os seguintes meios de cultura seletivos e não seletivo: agar sangue, agar sabouraud, Lowenstein jensen e agar legionella. Durante a coleta do ar, foram verificadas as seguintes variáveis: temperatura e a umidade relativa dos ambientes, número de pessoas presentes e equipamentos sendo utilizados na limpeza. Após as coletas, as amostras foram encaminhadas ao laboratório de ensaios microbiológicos da escola de enfermagem da Universidade de São Paulo, onde permaneceram em estufa microbiológica regulada a 35 ± 2ºC. Os dias de incubação foram específicos para recuperação pretendida de cada grupo microbiano quais sejam: bactérias vegetativas - incluindo Legionella, Mycobacterium tuberculosis e fungos. As placas com crescimento positivo foram submetidas a identificação do gênero e/ou espécie, por meio das características fenotípicas e reações específicas, pelo laboratório de microbiologia da Santa Casa de São Paulo. As amostras, tanto do CME com pressão negativa como naquele sem, foram coletas em quintuplicata. Resultados: a concentração de bioaerossóis na área da limpeza no CME sem pressão negativa e da área de preparo foi de 273,15 e 206,71 UFC/m3 respectivamente, enquanto, no CME com pressão negativa foi de 116,96 UFC/m3 na sala da limpeza e 131,10 na de preparo. Comparando a quantidade média de colônias isoladas dos CME estudados, a diferença foi significativamente menor (p=0,01541) no CME com pressão negativa. A relação I/E, onde I é a quantidade de fungos no ambiente interior e a quantidade de fungos no ambiente exterior, no CME com pressão negativa, na sala de limpeza foi de 0,5 e na sala de preparo de 0,58. No CME sem pressão negativa, a relação foi de 0,8 e 0,6, respectivamente, na sala de limpeza e preparo, ambos abaixo do padrão de referência, que deve ser 1,5, atualmente estabelecido pela resolução nº 9/2003 da ANVISA que dispõe sobre referenciais de qualidade do ar interior, em ambientes climatizados artificialmente de uso público e coletivo. Em nenhum dos CME foram recuperados Mycobacterium tuberculosis ou Legionella do ar. Os microrganismos identificados foram Penicillium spp, Aspergillus niger, Rhodotorula spp., Bacillus subtilis, e Micrococcus spp., todos considerados como não apresentando riscos à saúde em imunocompetentes. Conclusão: Os achados da presente investigação evidenciaram que o sistema de pressão negativa na sala de limpeza do CME contribuiu para redução quantitativa de bioaerossóis, tanto nesse ambiente como na sala de preparo. Entretanto, mesmo no CME sem esse sistema de tratamento do ar na sala de limpeza, a concentração de bioaerossóis foi menos da metade do padrão referencial estabelecido pela resolução nº 9/2003 da ANVISA, em que o valor máximo permitido deve ser 750 UFC/m3 de fungos. Ressalta-se que a quantidade e tipo de microrganismos existentes em qualquer ar ambiente é circunstancial, instável e principalmente dependente dos disseminadores microbianos presentes no local, sejam pessoas ou atividades. Nesse sentido, não se condena conclusivamente CME que não dispõe de pressão negativa na sala de limpeza configurando risco ocupacional. / Introduction: National (RDC ANVISA 15/2012) and international guidelines recommend that areas for cleaning medical devices in the Material and Sterilization Center maintain a negative differential ambient air pressure (BRAZIL, 2012; AAMI, 2006; ASHARE, 2013). However, this recommendation, so far, has not been supported by highly scientifically rigorous studies. Although there are no explicit justifications for such recommendations, it can be assumed that they are grounded on the risk of airborne microorganism contamination from the cleaning area to adjacent ones, which constitutes occupational risk. Objective: to evaluate the impact of negative air pressure on the microbiological quality of the air in the Material and Sterilization Center area where medical devices are cleaned and in the adjoining preparation room. Methods: Microbiological air samples were collected from the room where medical devices are cleaned (also called dirty room) and from the room where these devices are prepared (clean room) at two class II Material and Sterilization Center in the same hospital, located in the city of São Paulo: with and without a negative air pressure system in the cleaning room; the latter with central air conditioning. As a control, outdoor air samples were collected. To obtain microbiological air samples, Andersen six-stage air sampler was used, with the following selective and non-selective culture media: blood agar, sabouraud agar, Lowenstein Jensen and agar legionella. During air collection, the following variables were controlled: temperature and air relative humidity in the rooms, number of people present in the sites and equipment used for the cleaning. After the collection, the samples were sent to the Laboratory of Microbiological Trials of the Nursing School of the University of São Paulo, where they remained in a microbiological oven at a temperature of 35ºC ± 2. The incubation period was specific for the intended recovery of each microbial group: vegetative bacteria including Legionella and Mycobacterium tuberculosis and fungi. Identification of microorganisms` genus and / or species was carried out according to their phenotypic characteristics at the Microbiology Laboratory of the Santa Casa Hospital in São Paulo. The samples, in both Material and Sterilization Center, the one with negative pressure and the one without, were collected in a five-fold sample. Results: The concentration of bioaresols in the cleaning room and preparation area without negative pressure was 273.15 and 206.71 UFC / m3, respectively, while in the Material and Sterilization Center with negative pressure the concentration of bioaerosols was 116.96 CFU / m3 in the cleaning room, and 131.10 in the preparation area. The number of isolated colonies in the negative pressure Material and Sterilization Center was significantly lower (p = 0.01541). The I / E ratio, where I is the amount of fungi in the indoor environment, and E is the amount of fungi in the outdoor environment, in the cleaning room of the negative pressure Material and Sterilization Center was 0.5, and in the preparation area, 0, 58; as for the Material and Sterilization Center without negative pressure, in the cleaning and in the preparation area, the ratio was 0.8 and 0.6, respectively, both below the reference standard currently established by ANVISA Resolution No. 9/2003, which determines indoor air quality standards at artificially climatized environments for public use. In neither of the studied Material and Sterilization Center were Mycobacterium tuberculosis or Legionella recovered from the air. The microorganisms identified were Penicillium spp, Aspergillus niger, Rhodotorula spp., Bacillus subtilis, and Micrococcus spp., all of which are considered harmless to immunocompetent subjects. Conclusion: The findings showed that the negative pressure system in the Material and Sterilization Center cleaning room contributed to the quantitative reduction of bioaerosols, both in this area and in the adjoining preparation area. However, even in the Material and Sterilization Center whose cleaning room did not have this system the concentration of bioaerosols was less than half the reference standard established by ANVISA Resolution No. 9/2003. It should be stressed that the quantity and type of microorganisms in any ambient air is circunstancial, instable and, especially dependent on microbe disseminators in the site, whether they are people or activities. Therefore, it cannot be conclusively concluded that Material and Sterilization Center that do not have negative pressure in their cleaning rooms offer occupational risk.
1258

[en] SYNTHESIS AND CHARACTERIZATION OF LOW THERMAL EXPANSION OXIDES / [pt] SÍNTESE E CARACTERIZAÇÃO DE ÓXIDOS COM BAIXA EXPANSÃO TÉRMICA

MONICA ARI SANO 19 February 2008 (has links)
[pt] Materiais que apresentam expansão térmica baixa ou negativa possuem grande potencial de emprego em diversas aplicações que requerem resistência ao choque térmico, assim como para aplicações odontológicas, em placas de circuitos eletrônicos, em componentes ópticos e para produzir compósitos em que compensam a expansão térmica positiva de outros materiais. Por este motivo, o estudo e a produção de materiais com expansão térmica controlada têm crescido nos últimos anos. No presente trabalho, foram estudadas algumas famílias de óxidos com estruturas que apresentam este tipo de comportamento. Foi avaliada a expansão térmica em três sistemas da família A2M3O12 com o intuito de produzir materiais com expansão térmica controlada pela substituição química do cátion A pelos cátions Al, Cr e Fe. Os sistemas produzidos foram: Cr2xFe2-2xMo3O12 (molibdato de cromo - ferro), Al2xCr2- 2xMo3O12 (molibdato de alumínio - cromo) e Al2xFe2-2xMo3O12 (molibdato de alumínio - ferro). Além destes, o composto HfMgMo3O12 foi também sintetizado para testar a viabilidade de substituição dos cátions A trivalentes por um cátion divalente e um tetravalente. Foi possível obter soluções sólidas monofásicas e seus parâmetros de rede variam linearmente com o aumento no conteúdo do cátion de maior tamanho, conforme a lei de Vegard. Análise térmica realizada por DSC permitiu determinar a temperatura de transição de fase da estrutura monoclínica (P21a) à ortorrômbica (Pbcn). Os valores encontrados foram: para o Al2Mo3O12, 200oC, para o Cr2Mo3O12 , 403oC e para o Fe2Mo3O12, 512oC. Coeficientes de expansão térmica intrínsecos foram determinados por difração de raios-X utilizando luz síncrotron, encontrando-se valores bem reduzidos para todos os sistemas estudados, a saber: para o Al2Mo3O12, (alfa)l = 2,32 x 10- 6/oC, para o Cr2Mo3O12 , (alfa)l = 0,65 x 10-6/oC e para o Fe2Mo3O12, (alfa)l = 1,72 x 10-6/oC. / [en] Negative and low thermal expansion materials have important potential applications as resistance to thermal shock, as well as, for odontological applications, printed circuit boards, optical components and to produce composites to compensate the positive thermal expansion of materials. For this reason, the study and production of materials with controlled thermal expansion have increased in the recent years. In the present work, some oxide families with structures that present this type of behavior were investigated. The thermal expansion in three systems of A2M3O12 family was evaluated in order to produce materials with controlled thermal expansion through the chemical substitution of cation A with Al, Cr and Fe. The produced systems were: Cr2xFe2-2xMo3O12 (chromium - iron molybdate), Al2xCr2-2xMo3O12 (chromium - aluminum molybdate) and Al2xFe2-2xMo3O12 (aluminum - iron molybdate). Besides that, HfMgMo3O12 was synthesized to test the viability of substitution of trivalent cations for one divalent plus one tetravalent. It was possible to obtain single- phase solid solutions and their lattice parameters increased linearly with the increase of the largest cation content, following the Vegard`s law. Thermal analysis carried out by DSC allowed the determination of the phase transition temperature from monoclinic (P21a) to orthorhombic (Pbcn) structure. The values were 200oC for Al2Mo3O12, , 403oC for Cr2Mo3O12 , and 512oC for Fe2Mo3O12. Intrinsic thermal expansion coefficients were determined by X-rays diffraction using syncrotron radiation, and low values were found for all studied systems: (alfa)1 = 2,32 x 10- 6/oC for Al2Mo3O12, (alfa)1 = 0,65 x 10-6/oC for Cr2Mo3O12 , and (alfa)1 = 1,72 x 10-6/oC for Fe2Mo3O12.
1259

Avaliação de proteases extracelulares de linhagem Chryseobacterium sp. Kr6 e purificação e caracterização de uma metaloprotease queratinolítica / Evaluation of extracellular proteases from Chryseobacterium sp. Kr6 strain and purification and characterization of a keratinolytic metalloprotease

Riffel, Alessandro 17 March 2006 (has links)
A linhagem queratinolítica Chryseobacterium sp. Kr6 mostrou-se com possibilidade de aplicação em processos envolvendo queratinólise, principalmente na hidrólise de penas de frango e depilação de couro bovino. No presente trabalho avaliou-se o efeito da composição do meio sobre o crescimento e atividade proteolítica deste isolado e uma protease queratinolítica (queratinase) foi purificada e caracterizada. O microrganismo mostrou-se adaptado à utilização de queratina como substrato durante o crescimento, produziu diferentes proteases dependendo do meio utilizado e a maior atividade proteolítica foi atingida quando utilizado meio de cultivo com penas como única fonte de carbono e nitrogênio. A adição de fonte extra de nutrientes resultou em uma parcial repressão catabólica. Uma protease extracelular (Q1) foi purificada cerca de 14 vezes utilizando cromatografia de interação hidrofóbica em Phenyl-Sepharose CL 4B e gel filtração em Superose H12R. Q1 mostrou ser uma proteína monomérica com peso molecular de 64 KDa determinado por SDS-PAGE e pH e temperatura ótimos de 8,5 e 50°C respectivamente. O perfil de inibição indica tratar-se uma metaloprotease e as seqüências internas dos peptídeos resultantes de digestão tríptica mostraram homologia ao sítio ativo e de ligação ao Zn da família M14 (Carboxipeptidase). A atividade proteolítica foi estimulada pela presença de íons Ca2+ e Mg2+ e inibida por Cu2+, Zn2+, Al2+, Hg 2+ e agentes redutores. Q1 apresentou atividade queratinolítica sobre o substrato keratin azure, mas não foi capaz de hidrolisar penas de frango sugerindo a necessidade de outras enzimas durante o processo de degradação de penas. Utilizando os iniciadores degenerados desenhados com base na seqüência dos peptídeos, foi amplificado um fragmento de 470 pb correspondente a uma região do possível gene desta metaloproteína utilizando DNA e cDNA como molde. A seqüência do fragmento pode estar sendo expressa, mas não apresentou similaridade e homologia a proteínas conhecidas e portando, indicativa de uma nova metaloprotease. / The strain Chryseobacterium sp. kr6 shown to be useful for biotechnological purposes such as hydrolysis of poultry feathers and de-hairing of bovine pelts. The effect of media composition on the protease production and growth by this strain was studied and a keratinolytic protease (keratinase) was purified and characterized. The strain was adapted to use keratin as substrate to growth, produced different proteases in different media composition and the higher proteolytic activity was reached when used feather as only source of carbon and nitrogen. The addition of sources of nutrients has resulted in partially repressed catabolism. An extracellular protease Q1) was purified 14-fold by chromatography using the hydrophobic interaction Phenyl-Sepharose CL 4B column and gel filtração in Superose 12HR. SDS-PAGE indicated that the Q1 is a monomeric protein with molecular mass of 64 KDa. and optima pH and temperature were 8,5 e 50°C, respectively. The inhibition profile indicates to be a Zn-metalloprotease and analysis of tryptic peptides sequence revealed sequence homology to the conserved active site and Zn binding site, which may characterize keratinase Q1 as a member of M14 metalloprotease family (Carboxipeptidase). The activity was stimulated by of Ca2+ and Mg2+ and inhibited by Cu2+, Zn2+, Al2+, Hg 2+ and reducing agents. Q1 presented keratinolytic activity under substrate keratin azure, but was unable to hydrolyze poultry feather, suggesting the requirement by other enzymes in the feather hydrolysis mechanism. Degenerate primers amplified a 470 bp, corresponding to a probable gene region of this metalloprotein, with DNA and cDNA. The sequence is being expressed but do not showed similarity and homology to known proteins, thus indicating a new metalloprotease.
1260

Efeito da suplementação prolongada de grão de soja cru e integral no pré-parto sobre o desempenho produtivo, qualidade oocitária e embrionária, e função imune de vacas leiteiras / Effect of prolonged supplementation with raw whole soybean during prepartum on productive performance, oocyte and embryo quality, and immune function of dairy cows

Gardinal, Rodrigo 11 March 2016 (has links)
Objetivou-se avaliar o efeito da suplementação prolongada de grão de soja cru e integral (GSI) como fonte de ácido graxo &#937;6 sobre o desempenho produtivo, perfil metabólico, qualidade oocitária e embrionária e função imune de vacas leiteiras no período de transição e início de lactação. Foram selecionadas 44 vacas da raça Holandesa, multíparas e gestantes, com parto previsto para 90 dias após o início da avaliação e fornecimento das dietas experimentais, porém em razão da ocorrência de enfermidades metabólicas ou infecciosas (3 abortos; 3 deslocamentos de abomaso; 3 enfermidades podais; 4 distocias) 13 animais foram retirados do experimento. As vacas foram distribuídas aleatoriamente em quatro grupos experimentais diferindo entre eles o início do fornecimento de grão de soja cru e integral (GSI) durante o pré-parto. A dieta era baseada na inclusão de 12% de GSI %MS, com aproximadamente 5,1% de extrato etéreo (EE) o início de seu fornecimento foi conforme descrito a seguir: Grupo 0: Animais não receberam dieta contendo GSI no pré-parto; Grupo 30: Início do fornecimento de dieta com GSI nos 30 dias finais da gestação; Grupo 60: Início do fornecimento de dieta com GSI nos 60 dias finais da gestação; Grupo 90: Início do fornecimento de dieta com GSI nos 90 dias finais da gestação. Após o parto, todas as vacas receberam dieta única com 5,1% de EE, baseada na inclusão de 12% de GSI %MS até 90 dias de lactação. Os animais foram arraçoados de acordo com o consumo de matéria seca no dia anterior, de forma a ser mantido porcentual de sobras das dietas, diariamente, entre 5 e 10%. As amostras dos alimentos e sobras foram coletadas diariamente e armazenadas a -20ºC. Semanalmente as amostras coletadas diariamente foram misturadas e foi retirada uma amostra composta referente a um período de uma semana, a fim de mensurar o consumo de matéria seca e nutrientes. Amostras de fezes foram coletadas nos dias -56, -21, 21, 56 e 84 dias em relação ao parto, com o propósito de mensurar a digestibilidade da matéria seca e nutrientes. A produção de leite foi mensurada diariamente e para a composição dos teores de gordura, proteína, lactose e perfil de ácidos graxos amostras foram coletadas semanalmente. As amostras de sangue para análise dos metabólitos sanguíneos foram coletadas semanalmente. Amostras de sangue para mensurar a atividade do sistema imune foram coletadas na semanas -8, -4, -2, -1 em relação ao parto, parto, +1, +2, +4 e +8 semanas no período pós-parto. Nos dias 21, 42, 63 e 84 do período pós-parto foram realizadas aspirações foliculares, com posterior fertilização in vitro dos oócitos. Todas as variáveis mensuradas foram analisadas pelo procedimento PROC MIXED do SAS 9.4 através de regressão polinomial, utilizando efeito fixo de tratamento, semana, interação tratamento*semana e efeito de animal dentro de tratamento como aleatório. Utilizou nível de 5% de significância. Foi observado efeito (P<0,05) linear crescente para CEE no pré-parto. Não foi observado diferenças no CMS e nutrientes no pós-parto. Não houve alteração da digestibilidade nos períodos pré e pós-parto. Não houve alteração no balanço de energia e nitrogênio nos periodos pré e pós-parto. Não foi observado diferença na produção, composição e teor dos componentes totais do leite. No perfil de ácidos graxos do leite houve efeito (P<0,05) linear descrescente para as concentrações de C16:1cis, C18:1 cis, total de C:18 insaturado, total de AG monoinsaturados, insaturados e a relação do total de AGS:AGI. Foi observado efeito linear (P<0,05) crescente para o total de AG aturado e efeito (P<0,05) quadrático para C18:2, CLAcis9-trans11, e total de AGPI. Foi observado efeito linear crescente (P<0,05) para colesterol total, LDL no préparto e linear decrescente (P<0,05) para GGT nos períodos pré e pós-parto. Foi observado efeito quadrático (P<0,05) para HDL no pré-parto e AST no pós-parto. Em relação a atividade do sistema imune foi observado efeito linear (P<0,05) crescente para o percentual de CD3+ ativos no pós-parto, para o percentual de monócitos que produziram espécie reativa de oxigênio (ERO) no pós-parto quando foram estimulados por S.aureus e E.coli e para a intensidade de imunofluorescência de ERO para ganulócitos no pós-parto quando estimulados por S.aureus. Foi observado efeito (P<0,05) quadrático para o percentual de granulócitos, mononucleares, CD8+ ativos no pós-parto e para o percentual de granulócitos que produziram ERO no pós-parto quando estimulados por E.coli. A suplementação prolongada com GSI no pré-parto melhora a atividade do sistema imune, não melhora a qualidade oocitária e embrionária bem como não influencia negativamente os parametros produtivos de vacas leiteiras no período de transição e início de lactação / The objective was to evaluate the effect of prolonged supplementation with whole soybean grain (WSG) as a source of &#937;6 fatty acid on the productive performance, metabolic profile, oocyte and embryo quality, and immune function of dairy cows during the transition period and early lactation. Forty-four multiparous, pregnant Holstein cows, with calving predicted to 90 days after the beginning of the evaluation and supply of the experimental diets were selected. However, due to the occurrence of metabolic or infectious disorders (3 abortions, 3 displaced abomasums, 3 foot disorders, 4 dystocias), 13 animals were removed from the experiment. Cows were randomly assigned to one of four experimental groups, which differed in period of supply of whole soybean grains during the prepartum. The diet was based on 12% of WSG (%DM) and had approximately 5.1% of ether extract (EE). Diet supply was as follows: Group 0) control diet not containing WSG; Group 30) WSG supply starting 30 days before predicted calving date; Group 60) WSG supply starting 60 days before predicted calving; Group 90) WSG supply starting 90 days before predicted calving date. After calving, all cows received a single diet with 5.1% EE, based on inclusion of 12% WSG (%DM) until 90 days of lactation. Animals were fed ad libitum to ensure between 5 and 10% orts daily. Dry matter and nutrients intake were evaluated. Samples of feeds and orts were collected daily and stored at -20°C. Samples were composited weekly and analyzed for chemical and bromatological characteristics. Feces samples were collected on days -56, -21, 21, 56, 84 (related to the predicted calving), in order to measure the digestibility of dry matter and nutrients. Milk yield was measured daily and milk samples were collected weekly for evaluation of fat, protein and lactose percentages, and fatty acids profile. Blood samples were taken weekly for analysis of blood metabolites. To measure the activity of the immune system, blood samples were collected at weeks -8, -4, -2, -1 prepartum, at calving, and at weeks +1, +2, +4, +8 postpartum. On days 21, 42, 63 and 84 postpartum, follicular aspirations were performed, with subsequent in-vitro fertilization of the oocytes. All measured variables were analyzed using PROC MIXED of SAS 9.4 through polynomial regression, considering as fixed effects the dietary treatment, week and interaction treatment*week, and animal as random effect. The 5% level of significance was considered. A crescent linear effect was observed (P <0.05) for prepartum ether extract intake. There was no difference in dry matter and nutrients intake during the postpartum period. There were no differences in digestibility pre and postpartum. No difference in energy and nitrogen balance during pre and postpartum periods was observed. Milk production and composition did not differ among dietary treatments. When evaluating the milk fatty acids profile, a decreasing linear effect was noted (P<0.05) for the concentrations of C16:1 cis, C18:1 cis, total unsaturated C18, total monounsaturated fatty acids, total unsaturated fatty acids and total SFA:UFA ratio. There was an increasing linear effect (P<0.05) for the total of saturated fatty acids and a quadratic effect (P<0.05) for C18:2, CLAcis9-trans11, and total PUFA. It was observed increasing linear effect (P<0.05) for total cholesterol and LDL in the prepartum period, and decreasing linear effect (P<0.05) for GGT in the pre and postpartum. We observed a quadratic effect (P<0.05) for HDL in prepartum and for AST during the postpartum. Regarding the activity of the immune system, there was a crescent linear effect (P<0.05) for the percentage of active CD3+ in the postpartum period, for the percentage of monocytes producing reactive oxygen species (ROS) during postpartum period when stimulated by S. aureus and E. coli, and for granulocytes ROS immunofluorescence intensity during postpartum when stimulated by S. aureus. Quadratic effect was observed (P<0.05) for the percentage of granulocytes, mononuclear cells, active CD8+ in the postpartum period and the percentage of granulocytes that produced ROS when stimulated by E. coli. Prolonged supplementation with RWS in the prepartum improves the activity of the immune system, however it does not improve oocyte and embryo quality and does not adversely affect the production performance of dairy cows during the transition period and early lactation

Page generated in 0.0427 seconds