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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Effects of individual and combinatorial electrolyte solutions comprised of various carbohydrates, salts, and stimulants injected into broiler hatching eggs on subsequent late term embryogenesis and post hatch performance through tendays of age

McGruder, Brenna Mariechen 03 May 2008 (has links)
In this study, the effects of individual and combinatorial electrolyte solution comprised of carbohydrate, salt, and a stimulant injected into broiler hatching eggs on subsequent late term embryogenesis and post hatch performance up to D 10 were evaluated in separate trials. The effects of solution concentration and volume on embryo body weight and yolk reserves were likewise considered, and limited posthatch growth, body weight, and yolk sac effects of a compound electrolyte solution were evaluated. The individual and combinatorial effects of injected solutions were examined in an effort to yield the maximum physiological growth effects on embryogenesis from the metabolic pathways in which these compounds are involved. Limited effects on embryo and post hatch mortality were found. However, both post hatch yolk reserves and liver weights were affected by in ovo injection. These effects could be key in increasing bird weight by processing day.
122

Studies on T-cell Properties during Coccidiosis and a Vitamin E Supplement to an<i> in ovo</i> Coccidiosis Vaccine

Walston, Matthew W. S. January 2014 (has links)
No description available.
123

In ovo and feed application of probiotics or synbiotics and response of broiler chicks to post-hatch necrotic enteritis

White, Mallory Beth 04 June 2021 (has links)
Immediately post-hatch, broiler chicks are exposed to microbes that begin colonizing the gut, including environmental pathogens. One of the costliest enteric diseases in broiler production is necrotic enteritis (NE), caused by the ubiquitous opportunistic bacteria Clostridium perfringens (CP). With the worldwide reduction in antibiotic growth-promoters (AGPs), there is increased interest in natural alternatives to reduce disease and improve broiler health. The overall objective of the studies described herein was to apply probiotics or synbiotics to birds by in ovo application or orally before they leave the hatchery, then evaluate bird performance and various intestinal responses. Data were analyzed in JMP with LS Means to separate means with significance assigned at P ≤ 0.05 and trends at 0.05 < P ≤ 0.10. The first 21-day (D) study used 480 male Cobb 500 broilers randomly divided into one of four treatments using a 2x2 factorial design: a no-additive control (CTRL), a one-time oral application of synbiotic at the hatchery fed a basal diet (HS), an oral application of water at the hatchery with dietary synbiotics (DS), and a hatchery synbiotic plus dietary synbiotic (HSDS). Performance was measured on day-of-hatch (DOH), D3, D7, D14, and D21. mRNA abundance of various intestinal markers was measured at D7 and D21, including tight junction proteins ZO-1, ZO-2, and CLD-1; nutrient transporters SGLT1 and PepT1; and immune response markers TLR2, TLR4, and IL-10. HS lowered feed intake (FI) and feed conversion ratio (FCR) without lowering body weight (BW) from D14-21. There was greater abundance of PepT1 mRNA (P ≤ 0.1) and IL-10 mRNA (P ≤ 0.05) on D21 in HSDS. Second, a 21-day pilot study with 480 male and female Cobb 500 broilers was conducted to determine the optimum in ovo dosage level of a probiotic or synbiotic (PROB or SYNB) applied at embryonic day 18 (E18) with subsequent NE challenge using seven treatments: in ovo application of sterile water (CTRL), low (PROB-L or SYNB-L: 1x105 CFU), medium (PROB-M or SYNB-M: 1x106 CFU), or high (PROB-H or SYNB-H: 1x107 CFU) probiotic or synbiotic doses dissolved in sterile water. Performance measurements were taken on DOH, D4, D8, D14 and D21. On D8, NE lesion scores were not impacted by treatment. D8 ileal samples were taken for mRNA abundance of TLR4, IL-10, IL-1β, AvBD8, AvBD10, and AvBD13. SYNB-H had higher abundance of AvBD10 mRNA compared to CTRL (P ≤ 0.1), and higher IL-1β mRNA compared to SYNB-L (P ≤ 0.05). PROB-H and SYNB-H had better performance than the low and medium doses, but were not better than the CTRL. The high doses were chosen for subsequent studies. Third, a longer 42-day study using 1,630 Ross 708 male and female broilers was conducted consisting of the following six treatments. A negative control (NC): sterile water in ovo fed basal corn/soybean meal mash diet without NE challenge; antibiotic growth-promoter (AGP+): sterile water in ovo fed basal diet with virginiamycin (0.5 kg/MT) as an AGP with NE challenge; NC+: same as NC plus NE challenge; SI+: synbiotic in ovo fed the basal diet and NE challenged; SD+: sterile water in ovo fed basal diet supplemented with synbiotic (0.5 kg/MT feed) and NE challenged; and SID+: synbiotic in ovo fed basal diet with synbiotic (0.5 kg/MT feed) with NE challenge. Cumulatively, SID+ had lower FI and FCR than NC+, but no change in BW or BWG. The combination treatment (SID+) often had an additive effect compared to SD+ or SI+ alone on mRNA abundance and D7 cecal fatty acid profiles. SD+ and SID+ also had higher D42 lean:fat ratios compared to NC+. Last, a 42-day study was conducted using 1,630 male and female Ross 708 broilers and the in ovo application of probiotics and subsequent NE challenge with five treatments. NC: sterile water in ovo, fed basal corn/soybean meal mash diet without NE challenge; AGP+: sterile water in ovo, fed basal diet with virginiamycin (0.5 kg/MT of feed) as AGP with NE challenge; NC+: NC treatment, with NE challenge; PI+: probiotic in ovo, fed basal diet, with NE challenge; PD+: sterile water in ovo, fed basal diet supplemented with probiotic (1.3 kg/MT of feed), with NE challenge. The use of probiotics in this study had little effect on performance, lean:fat ratios, and cecal fatty acid profiles, but PD+ increased mRNA abundance of D14 TLR2, D14 TNF-α, and D42 LEAP2 in cecal tonsils compared to controls. PI+ increased mRNA abundance of D7 and D42 MUC2, D7 LEAP2, and D42 TNF-α in the ileum. PI+ increased mRNA abundance in the cecal tonsils of D7 TLR2 and D42 TNF-α. These studies yielded interesting results about probiotics and synbiotics during a NE challenge by evaluating performance, intestinal immune responses, and fatty acid profiles in the ceca of broilers. In conclusion, the probiotic in this study did not improve broiler health during a NE challenge, but synbiotic use in ovo and continuation in the feed showed improvement over in ovo or dietary application alone. Synbiotic improved FCR over a challenged control, and altered mRNA abundance in the small intestine. / Doctor of Philosophy / The poultry industry is one of the most popular animal protein sources worldwide. As with any livestock operation, industry goals include optimizing animal health and well-being, maximizing animal productivity, and producing quality products in the most cost effective manner. Improvements in genetics, nutrition, and management have increased productivity and cut costs. One important application was the low-level use of antibiotics in feed. These medications reduced the risk of disease outbreak in flocks, which led to healthier birds and improved growth rates. However, when global concern of antibiotic resistance in human medicine came to light, both the livestock industry and governing bodies implemented voluntary and mandatory reduction or elimination of antibiotics. Previously, these important antibiotics helped to control costly diseases. As they are removed, alternatives to antibiotics will be important in disease control and prevention. A major group of alternatives to antibiotics in poultry includes probiotics, prebiotics, and synbiotics. Probiotic bacteria are considered 'good bacteria' in the gut, and provide various health benefits to the host. Prebiotics are non-living substances that support the growth of healthy bacteria. A synbiotic is the combination of both probiotics and prebiotics in a single application method. The goal of this research project was to give probiotics or synbiotics to broiler chicks and evaluate their potential benefits and effects on bird performance and the immune response. Ideally, applying probiotic bacteria as early as possible might translate into early colonization of the gut with healthy bacteria. This included oral application of synbiotics at the hatchery, or by safely injecting them into part of the egg that is swallowed by the chick embryo before hatch. This egg application, or in ovo application, is a safe, effective, widely-practiced method of vaccinating chicks to jumpstart their defense against disease. By vaccinating them in ovo, they can start to prime the immune system before they even hatch. Applying probiotics in ovo may improve health after early gut colonization with beneficial microbes. Numerous studies on natural alternatives to antibiotics have been conducted, with varying results. Results of this research indicate that in ovo application of probiotics and synbiotics is safe. Birds that received probiotics in the feed often performed similar to those that received none. However, the in ovo use of synbiotics combined with the continued use in the feed after hatch improved efficiency in broilers during an intestinal disease challenge and improved various aspects of gut function. Overall, as antibiotics are phased out, using probiotics and synbiotics may improve poultry health, but continued research will help understand the optimum ways to use them.
124

Medidas de risco em otimização de portfolios / Risk measures in portfolio optimization

Bueno, Luís Felipe Cesar da Rocha, 1983- 25 February 2008 (has links)
Orientador: Jose Mario Martinez Perez / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-10T15:09:35Z (GMT). No. of bitstreams: 1 Bueno_LuisFelipeCesardaRocha_M.pdf: 1111693 bytes, checksum: 531a933822f5dcf9cacad7dea6be5f53 (MD5) Previous issue date: 2008 / Resumo: Nesta dissertacao fazemos uma exposicao sobre alguns modelos matematicos com aplicacoes em economia. Dentre os modelos estudados destacamos a versao discreta das populares medidas de risco VaR (Value at Risk ) e C-VaR (Conditional Value at Risk ). Discutimos algumas propriedades de tais medidas, e, principalmente, expomos sobre algumas ideias para otimiza-las sob uma formulação do tipo OVO (Order Value Optimization) e propomos uma nova formulação para o problema de minimizar a VaR / Abstract: In this dissertation we make a presentation on some mathematical models with applications in economics. Among the studied models we highlight a discrete version of the popular risk measures VaR (Value at Risk) and C-VaR (Conditional Value at Risk). We discuss about some properties of such measures, and, above all, expose on some ideas for optimizing the VaR and CVaR under a OVO (Order Value Optimization) formulation and propose a new formulation to the problem of minimizing the VaR / Mestrado / Otimização / Mestre em Matemática Aplicada
125

"ÄTA BÖR MAN, ANNARS DÖR MAN" : En studie om möjligheten till implementering av lakto-ovo-vegetarisk och ekologisk kost i Eskilstuna kommuns förskola

Bergström, Emelie, Bird, Johanna January 2014 (has links)
The purpose of this study was to describe the possibility of implementing a lacto-ovo-vegetarian and organic diet in Eskilstuna municipality’s public preschool. Furthermore the purpose was to identify and describe the most important components involved in the implementation and their influence in the process.  The methods used were a survey based on a literature study. This study includes general information about meat production and consumption and also the use of pesticides in farming. It also brings up the environmental and health effects caused by the previously mentioned areas. The effects caused by meat production and consumption are, among others, greenhouse gas emissions and increased risk of some forms of cancer. The effects of pesticides are not fully stated but present studies indicate that the effects, especially regarding the environment, are negative. The study then narrows and describes the situation and organization in Eskilstuna municipality and finally describes the possible implementation process. The conclusion of the study was that an implementation is possible and a needed step towards a reduction of negative environmental and health impact. Learned habits that are created in an early age can act as a base for present and future challenges. Children will become the consumers of the future. An organic and lacto-ovo-vegetarian diet reduces the amount of antropogenic distributed compounds and greenhouse gases to the environment and can function as an instrument towards the achievement of the Swedish Environmental Objectives. Goals that are set by Eskilstuna municipality can also be favored by an implementation of the suggested diet in the public preschool.
126

Поэтика зачинов в новеллах Эдгара По : магистерская диссертация / Poetics of Beginnings in Edgar Allan Poe’s Short Stories

Наседкина, С. С., Nasedkina, S. S. January 2022 (has links)
Магистерская диссертация посвящена зачинам новелл Э. А. По как малоизученной области поэтики писателя. Цель работы – типологизация зачинов новелл Э. А. По на основании их лингвостилистических маркеров, характера предоставляемой в рамках зачина информации и мотивной наполненности. Актуальность исследования определяется отсутствием в науке общепринятой дефиниции зачина, критериев его делимитации, четкого понимания смыслового наполнения зачинов. Проанализировав существующие концепции теоретических описаний зачинов художественного текста, автор приходит к выводу об их недостаточности и конструирует собственное определение и собственную типологию зачинов для новелл Э. А. По, опираясь на эмпирические материалы исследования. Под зачином понимается первый абзац как содержательно-тематический блок, выделенный в соответствии с экспрессивно-образной авторской установкой. Проводится анализ нарративной субъектной организации зачинов, выделяются экспозиционные (интродукция персонажей, места и времени действия), композиционно-стилистические мотивы (апелляция к читателю, рассуждения), вариации приема «вырезанное начало». В результате исследования зачины были дифференцированы, на основании 1) способа сюжетно-композиционной организации рассказа (3 класса); 2) функции мотивов, преобладающих в зачине (11 подтипов). Отдельно рассматриваются особенности новаторской модели зачинов Э. А. По, где связь зачина с сюжетом условна, и сюжетная история служит иллюстративным материалом к изложенным в зачине тезисам. Материалом для исследования служат 66 новелл Э. А. По на английском языке из двухтомной антологии ‘The Complete Poems and Stories of Edgar Allan Poe’. / The master's thesis is devoted to the opening fragments of E. A. Poe's short stories as an understudied area of the writer's poetics. The aim of the study is to classify opening fragments (the beginnings) of E. A. Poe's short stories based on their linguistic and stylistic markers, the information provided within and the motif content. The relevance of the study is determined by the lack of a generally accepted definition of the opening fragment, criteria of its delimitation, a clear understanding of the concept and semantic content of the opening fragment in the literary and linguistics approaches. Having analyzed the available concepts of opening fragment’s theoretical descriptions in fiction texts, the author concludes their insufficiency and constructs his own definition and typology of opening fragments for the E. A. Poe’s short stories, based on the empirical research materials. The opening fragment is understood as the first paragraph of the work as a conceptual and thematic segment, allocated in accordance with the expressive and imaginative author's attitude. The analysis of narrative subjective organization of beginnings is carried out, and expositional (introduction of characters, place and time of action), compositional and stylistic motives (appeal to the reader, reasoning), variations of the ‘cut-off beginning’ technique are distinguished. As a result of the study, the opening fragments were differentiated: 1) according to the method of plot-compositional organization of the story (3 classes); 2) according to the functions of the motives prevailing in the opening fragment (11 subtypes). Separately, the features of the innovative model of E. A. Poe's opening fragments are considered, where the connection of the beginning with the plot is conditional, and the plot serves as illustrative material for the theses set out in the opening fragment. The material for the study is 66 original short stories by Edgar Allan Poe from the two-volume anthology ‘The Complete Poems and Stories of Edgar Allan Poe’.
127

VITRIFICATION AND CHORIOALLANTOIC MEMBRANE (CAM) CULTURE OF BOVINE OVARIAN TISSUE

2015 May 1900 (has links)
The overall objectives of this thesis were to develop a short-term culture system and to examine the effects of vitrification and short-term culture on the viability of fresh and vitrified bovine ovarian tissue and the follicles within. The first objective was to compare the health and development of preantral follicles in bovine ovarian tissue, as well as the neovascularization of these tissues, subjected to avian chorioallantoic membrane (CAM) culture with the traditional in vitro culture system. We hypothesized that the chorioallantoic membrane (CAM) of the chicken embryo is a 
more suitable culture system than traditional in vitro culture. Bovine ovaries were retrieved from a local abattoir and cortical pieces (1-2mm3) were randomly assigned to one of the following groups; control (fixed immediately), CAM or in in vitro culture. Ovarian tissue fragments from both groups were removed on D1, D3 and D5 of culture, fixed, sectioned (5μm) and stained with H&E. The numbers of healthy and degenerated follicles, primordial and activated preantral (primary and secondary), and the number of infiltrated bovine and avian blood vessels were determined using standard stereological procedures. All grafts placed on the traumatized CAM demonstrated increased neovascularization over time. The healthy primordial follicle density decreased over time concomitant with an increase in degenerated (primordial and activated preantral) follicles in both treatment groups. Healthy activated preantral follicle density did not differ between the two culture systems at a given time. In CAM group, blood vessel density increased over time (p = 0.015). The second objective of this thesis was to develop a suitable vitrification protocol for bovine ovarian tissue. The viability of bovine ovarian tissue vitrified using two non-permeating cryoprotectants (sucrose and trehalose) and two cryodevices (cryotop and cryovial) was assessed. We hypothesized that during vitrification the higher cooling rate on the cryotop (open vitrification method) will yield better post-thaw viability of bovine ovarian tissue as compared to the cryovial (closed vitrification method). We also hypothesized that trehalose is a superior non-permeating cryoprotectant to sucrose for vitrification of bovine ovarian tissue. The ovarian tissue was fragmented (1-2mm3) and divided into 6 different treatment groups. Tissues were vitrified in TCM199 supplemented with 15% EG, 15% DMSO, 20% calf serum and 0.5M sucrose or trehalose then placed in a cryovial or on a cryotop. After warming, the vitrified tissues were either immediately placed in 10% formalin (control) or on the chorioallantoic membrane of a 10-day old chicken embryo for 5 days. Follicles from control and vitrified tissue were observed under a light microscope for normal morphology and the total, normal and degenerated follicle densities were determined by standard stereological procedures. Sucrose and trehalose did not differ, nor was a difference observed between the cryovial and the cryotop for total, healthy or degenerated follicle density. Proportion of healthy follicles was higher in the control than all treatment tissues grafted to the CAM. All grafts placed on the traumatized CAM demonstrated presence of avian erythrocytes in the blood vessels after 5 days, but no difference was observed for blood vessel density among treatments. Lastly, the cooling rate of bovine ovarian tissue subjected to open and closed system devices for vitrification was evaluated. A thermocouple wire was used to determine the cooling velocity of 1-2mm3 fragments of bovine ovarian tissue placed on a cryotop (open system) or in a sealed cryovial (closed system). The cooling rate of tissues on the cryotop and in the cryovial was 7481±205.9° C/min and 664±26.0° C/min respectively. In conclusion, the CAM supported the bovine ovarian tissue, thus the CAM culture system may be considered an acceptable alternative to traditional in vitro culture system for bovine ovarian tissue. Furthermore, angiogenesis may be an additional indication of ovarian tissue health. The hypotheses of our second study were refuted. Results indicated that sucrose and trehalose, and the cryotop and cryovial were equally effective in vitrifying bovine ovarian tissue.
128

Testovani embryotoxicity psychofarmak metodou CHEST / Embryotoxicity testing of psychopharmacs using the CHEST method

Pavlovič, Ondřej January 2014 (has links)
Psychotropic drugs are commonly used group of pharmaceuticals, their main effect is to alter psychic condition, including mental diseases treatment. Symptoms of mental illnesses are more and more common, theref orenumber of patients diagnosed with mental illnes, and thus using psychotropics, is growing stronger. But using psychotropics during gestation is not without risks for mother and embryo itself. However, thanks to the absence of controlled human studies, the knowledge of emrbyotoxic effects of pschotropics is limited to casuistics, reported side effects and animal experimental studies. Many of those studies suggests emrbyotoxic potential of psychotropic drugs, on the other hand, others claim their safety. The goal of this thesis is to test at least some of them, using CHEST method, that allows us to observe direct effect of unmetabolized substance on chick embryo. In this thesis we tested selected psychotropics, very common antidepressant fluoxetine (prozac) and antipsychotic drug olanzapine, for embryotoxicity, using in ovo method CHEST with chick embryos as model organism. By bypassing the maternal organism and his metabolism, this method allows to observe direct effect of unmetabolized substance on chick embryo. Results revealed embryotoxic effect of fluoxetin in dosage 10-2 and 10-3 on 3rd and...
129

Evolução da viviparidade nas serpentes da tribo Hydropsini / Evolution of viviparity in snakes of the tribe Hydropsini

Braz, Henrique Bartolomeu Pereira 29 August 2013 (has links)
A oviparidade é o modo reprodutivo ancestral dos répteis e a viviparidade surgiu diversas vezes independentemente nos Squamata. O cenário evolutivo mais aceito para a evolução da viviparidade em répteis Squamata propõe que ela é uma adaptação a baixas temperaturas e que resulta de aumentos graduais e progressivos na quantidade de desenvolvimento embrionário ocorrendo dentro do útero antes da postura dos ovos. Essa transição é frequentemente tida como irreversível. No presente trabalho as cobras-dágua da tribo Hydropsini foram utilizadas como modelo para testar de forma comparativa diversas predições derivadas desse cenário. Especificamente, foi avaliado se a evolução da viviparidade na tribo (1) seria um fenômeno irreversível, (2) se ela seria associada a modificações na morfologia uterina e na espessura da casca do ovo e (3) se ela seria correlacionada a regiões de climas frios. Diferentes métodos de análise não corroboram a suposta irreversibilidade da viviparidade e sugerem que a oviparidade em algumas espécies possa ser resultado de reversões. A aquisição da viviparidade em Hydropsini foi acompanhada de modificações importantes na morfologia uterina que incluem a diminuição das dimensões das glândulas uterinas que secretam o material que compõe a casca de ovo. A hipótese de que os aumentos na retenção uterina são acompanhados por diminuição na espessura da casca do ovo não foi corroborada. Por fim, o teste das predições da hipótese do clima frio não obteve suporte para baixas temperaturas como pressão seletiva favorecendo a origem da viviparidade nos Hydropsini. Hipóteses alternativas para explicar a origem da viviparidade na tribo são exploradas. / Oviparity is the ancestral reproductive mode of reptiles and viviparity evolved multiple times independently in Squamata. The most accepted evolutionary scenario for the evolution of viviparity in squamate reptiles suggests that it is an adaptation to low temperatures and that it arises from progressive and gradual increases in the amount of intrauterine embryonic development before egg-laying. In this study, the water snakes of the tribe Hydropsini were used as model system to test, within a comparative framework, several predictions derived from the gradualist scenario for the evolution of viviparity in Squamata. Specifically, it was evaluated if the evolution of viviparity in the tribe (1) is an irreversible phenomenon, (2) if it is associated with changes in uterine morphology and eggshell thickness and (3) if it is correlated to cold climates. The different analytical methods used did not corroborate the irreversibility of viviparity and suggest that oviparity may be revolved in some species. The evolutionary acquisition of viviparity in Hydropsini was accompanied by important uterine changes, including the reduction of the glands that secrete the shell components. The hypothesis that the increases in egg retention are accompanied by decreasing eggshell thickness was not corroborated. Finally, it was not found support for the test of the predictions derived from the cold climate hypothesis for the evolution of viviparity in Hydropsini. Alternative hypothesis explaining this reproductive mode in the group were explored.
130

Novas percepções sobre o uso de lecitina de soja na criopreservação e fertilidade de espermatozoide bovino / New insights on the use of soybean lecithin on bovine sperm cryopreservation and fertility

Rodrigues, Mariana de Paula 21 February 2014 (has links)
A grande demanda por proteína animal e a importância que a criação bovina exerce sobre a economia nacional, vêm exigindo eficientes sistemas de produção. A preservação e disseminação da genética do rebanho bovino dependem de biotecnologias como a criopreservação espermática, inseminação artificial e fertilização in vitro. No entanto, atualmente muito tem sido discutido sobre o uso da gema de ovo nos diluidores seminais. Pois apresentam variabilidade em sua composição e risco de contaminação microbiológica. Em contrapartida, apesar dos diluidores sintetizados com lecitina de soja não fornecerem esses riscos, seus resultados não são muito satisfatórios na criopreservação espermática bovina. Com base na hipótese de que a suplementação do diluidor seminal à base de lecitina de soja com antioxidantes, preserve as características das células espermáticas de maneira tão eficiente quanto à gema de ovo, o objetivo do presente experimento foi comparar o efeito do diluidor à base de gema de ovo com o diluidor à base de lecitina de soja (com e sem antioxidantes), sobre a manutenção da funcionalidade e fertilidade de amostras espermáticas bovinas criopreservadas. Para tal, foram utilizadas amostras seminais de 20 touros Brangus, cujas colheitas foram realizadas pelo método de eletroejaculação e as amostras foram diluídas em 4 grupos de diluidores: LElecitina de soja (sem a adição de antioxidantes); LAlecitina de soja suplementada com ácido ascórbico (AA, 4,5mM); LS lecitina de soja suplementada com superóxido dismutase (SOD, 60UI/mL) e GOgema de ovo (sem adição de antioxidantes). O sêmen foi então, criopreservado de maneira automatizada. As amostras foram descongeladas e analisadas quanto aos testes laboratoriais de motilidade computadorizada do espermatozóide (CASA); integridade de membrana plasmática (eosina/nigrosina); integridade de membrana acrossomal (fast Green/ rosa bengala); atividade citoquímica mitocondrial (DAB); susceptibilidade do DNA à desnaturação (SCSA); índice de estresse oxidativo induzido (TBARS). Além disso, foram realizados testes para verificar o potencial de fertilidade das amostras espermáticas criopreservadas. A fertilidade in vivo foi realizada pela técnica de inseminação artificial em tempo fixo (IATF), utilizando 450 fêmeas bovinas, seguido de exame ultrassonográfico para avaliação de prenhez. Teste de fertilidade in vitro, foi realizado pela técnica de produção in vitro de embriões (PIV) com o uso de ovários de frigoríficos, a classificação do desenvolvimento embrionário e a avaliação da motilidade espermática foram promovidas no decorrer do processo. Os resultados demonstraram que o diluidor LE apresentou efeito na proteção espermática de maneira semelhante ao diluidor GO. No entanto a suplementação desse primeiro com antioxidantes é uma alternativa para melhorar ainda mais esse processo, já que a taxa de prenhez obtida nos grupos LA e LS é satisfatória em um programa de IATF. Ainda o grupo LS foi o que apresentou melhores resultados no processo de PIV. Concluindo que o diluidor à base de lecitina de soja suplementado com o antioxidante superóxido dismutase seria uma opção para a substituição definitiva dos diluidores sintetizados com gema de ovo. / Due to the great demand for animal protein and the importance that bovine breeding exert on national economy, efficient production systems have been required. Cattle genetics preservation and dissemination depend on reproductive biotechnologies such as sperm cryopreservation, artificial insemination and in vitro fertilization. However, the use of egg yolk-based extender is under discussion nowadays, once there is great variability in its composition and risks of bacteriological contamination. On the other hand, despite soybean lecithin-based extenders do not present these risks, satisfactory results, after bovine sperm cryopreservation, have not been reached yet. Based on the hypothesis that soybean lecithinbased extender supplemented with antioxidants, preserve the sperm cell characteristics so efficient as egg yolk does, the aim of the present experiment was to compare the effects of egg yolk-based extender and soybean lecithin-based extender (with and without antioxidants), on functionality and fertility maintenance of bovine cryopreserved sperm samples. For this, seminal samples from 20 Brangus bulls were used, collects were realized by eletroejaculation method and samples were diluted in 4 extenders group: LE-soybean lecithin-based extender (without antioxidant supplementation); LA- soybean lecithin supplemented with ascorbic acid (AA, 4,5mM); LS- soybean lecithin supplemented with superoxide dismutase (SOD, 60UI/mL) and GO-egg yolk-based extender (without antioxidant supplementation). Then, semen was cryopreserved by automatic method. Samples were thawed and analyzed by laboratorial tests such as computer assisted semen analysis (CASA); plasma membrane integrity (eosin/nigrosin); acrosome membrane integrity (fast green/ rose bengal); mitochondrial cytochemical activity (DAB); susceptibility of chromatin denaturation (SCSA); induced oxidative stress index (TBARS). Furthermore, tests for fertility potential of cryopreserved semen samples were performed. In vivo fertility was accessed by timed artificial insemination (TAI), 450 bovine females were inseminated, and ultrasonographical exam was realized for pregnancy detection. In vitro fertility test was accessed by embryo in vitro production (IVP), ovaries from slaughterhouses were used, embryo development classification and sperm motility were promoted during the process. Results indicate that sperm protection is similar between LE and GO extenders. However the antioxidant supplementation of soybean lecithin-based extender is a great alternative to improve the process of sperm protection, since pregnancy rate of LA and LS groups was satisfactory for a TAI program. Besides, LS group presented the best results on IVP process. In conclusion, soybean lecithin-based extender supplemented with superoxide dismutase would be a better option for a definite replacement of egg yolk-based extender for sperm bovine cryopreservation.

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