<p>A number of environmental pollutants have been shown to mimick the action of the female sex hormone estrogen and are, therefore, suspected to be responsible for reproductive abnormalities seen in wildlife. Test systems which can be used in hazard and risk assessment of chemicals with estrogenic effects are consequently needed. In this thesis, I propose the avian egg as an <i>in vivo</i> test system for estrogenic compounds. I conclude that malformation of the left testis and the Müllerian ducts (MDs: embryonic oviducts) in avian embryos can be used as endpoints to examine estrogenic activity of chemicals. MD malformation is more easily determined and thereby faster to use as an endpoint than histologically observed feminization of the testis. The usefulness of MD/oviduct malformations as biomarkers for estrogenic effects in wild birds should be considered. </p><p>The environmental pollutants bisphenol A (BPA) and <i>o,p´</i>-DDT induced similar effects as the synthetic estrogens, ethynylestradiol and diethylstilbestrol. BPA caused MD malformations in quail embryos and ovotestis formation in chicken embryos. <i>o,p´</i>-DDT induced MD malformations in both quail and chicken embryos and ovotestis in chicken embryos. The flame retardant, tetrabromobisphenol A did not induce estrogen-like effects in quail or chicken embryos, but showed a relatively high embryolethality. </p><p>Embryonic exposure to estrogen caused persisting malformations of the oviduct, as well as a changed distribution pattern of the enzyme carbonic anhydrase in the shell gland of adult females. Considering the crucial role of carbonic anhydrase in shell formation, such changes could result in decreased shell quality. I propose that eggshell thinning in avian wildlife could reflect a functional malformation in the shell gland that is induced by xeno-estrogens during embryonic development, rather than being caused by exposure of the adult bird to environmental pollutants. This hypothesis opens new possibilities for studying the mechanisms behind contaminant-induced eggshell thinning in birds.</p>

A number of environmental pollutants have been shown to mimick the action of the female sex hormone estrogen and are, therefore, suspected to be responsible for reproductive abnormalities seen in wildlife. Test systems which can be used in hazard and risk assessment of chemicals with estrogenic effects are consequently needed. In this thesis, I propose the avian egg as an in vivo test system for estrogenic compounds. I conclude that malformation of the left testis and the Müllerian ducts (MDs: embryonic oviducts) in avian embryos can be used as endpoints to examine estrogenic activity of chemicals. MD malformation is more easily determined and thereby faster to use as an endpoint than histologically observed feminization of the testis. The usefulness of MD/oviduct malformations as biomarkers for estrogenic effects in wild birds should be considered. The environmental pollutants bisphenol A (BPA) and o,p´-DDT induced similar effects as the synthetic estrogens, ethynylestradiol and diethylstilbestrol. BPA caused MD malformations in quail embryos and ovotestis formation in chicken embryos. o,p´-DDT induced MD malformations in both quail and chicken embryos and ovotestis in chicken embryos. The flame retardant, tetrabromobisphenol A did not induce estrogen-like effects in quail or chicken embryos, but showed a relatively high embryolethality. Embryonic exposure to estrogen caused persisting malformations of the oviduct, as well as a changed distribution pattern of the enzyme carbonic anhydrase in the shell gland of adult females. Considering the crucial role of carbonic anhydrase in shell formation, such changes could result in decreased shell quality. I propose that eggshell thinning in avian wildlife could reflect a functional malformation in the shell gland that is induced by xeno-estrogens during embryonic development, rather than being caused by exposure of the adult bird to environmental pollutants. This hypothesis opens new possibilities for studying the mechanisms behind contaminant-induced eggshell thinning in birds.

Orientador: Nelson Luis Cappelli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-13T07:46:45Z (GMT). No. of bitstreams: 1 Romanini_CarlosEduardoBites_M.pdf: 1656027 bytes, checksum: eacfb3ae714a9b008469fac75bd1149b (MD5) Previous issue date: 2009 / Resumo: Dentro do complexo econômico de produção de carnes, a avicultura se constitui na atividade mais dinâmica e o Brasil possui uma das mais desenvolvidas aviculturas comerciais do mundo. Diante das atuais exigências na qualidade e segurança do produto, a moderna indústria avícola brasileira tem progredido, essencialmente pela adoção crescente de novas tecnologias. Na cadeia toda, a incubação dos ovos representa a origem do processo, pois é responsável por transformar biologicamente ovos férteis em pintos de um dia de idade. Em escala industrial, utilizam-se máquinas incubadoras para reproduzir as condições naturais de incubação das aves, objetivando elevar, ao máximo, o índice de eclosão e a qualidade de nascimento dos pintos. Porém, o desenvolvimento embrionário no interior dos ovos é substancialmente afetado pelas condições ambientais da incubadora. Os embriões não são aptos para controlar as trocas térmicas e mássicas durante a incubação; assim, as principais variáveis ambientais que exercem influência no processo, como temperatura e umidade relativa do ar, necessitam ser criteriosamente ajustadas, pois manter as condições adequadas ao redor dos ovos é um ponto crítico de controle do processo. Conhecimentos das áreas de automação e controle são capazes de influenciar positivamente o rendimento na incubação, portanto, o sistema de controle deve garantir a estabilidade operacional para as condições do processo e suas variáveis, dentro de limites desejados. O controle fuzzy é o mais adequado, para processos que apresentam não-linearidades e comportamento transiente, uma vez que descrevem numa rotina, a experiência humana para controlar o processo. Diante desse contexto, propôs-se, no presente estudo, desenvolver uma arquitetura de automação composta por um sistema de controle fuzzy, para proporcionar um controle mais preciso das variáveis de interesse na incubação. O estudo foi desenvolvido em duas etapas, sendo: 1) ensaio experimental de identificação dinâmica e modelagem matemática de uma incubadora de estágio único; e 2) simulação do processo de incubação dos ovos. Foi desenvolvido um modelo computacional da incubadora composto pela representação matemática da incubadora, pelas interações de transferência de calor e massa entre os ovos e o ambiente e, pelo sistema de inferência fuzzy utilizado para controlar o processo de incubação. A simulação proporcionou a execução de diversos cenários operacionais da incubadora, possibilitando o ajuste adequado para o sistema de controle proposto. Obteve-se, como principal resultado o comportamento ao longo do tempo das seguintes variáveis: temperatura dos ovos e do ambiente, massa dos ovos, umidade relativa do ar, produção de calor embrionária, detalhes da interação entre ovo e ambiente e as condições de atuação da incubadora estudada. Os resultados obtidos foram comparados aos valores de referência da literatura, indicando diferenças mínimas entre a temperatura dos ovos e o seu valor de referência. Os resultados relativos à massa de ovos tiveram desempenho abaixo do esperado e, para tal, o sistema de controle precisa receber ajustes. De maneira geral, foram obtidos conhecimentos técnicos mais apurados da incubação, que podem ser úteis para implementação real do sistema de controle desenvolvido. / Abstract: Within the meat production economical complex broiler production is the most dynamic activity, and Brazil has one of the world most developed commercial broiler production. Facing today's needs in terms of quality and safety of the product, modern Brazilian poultry production has improved essentially by the increasing adoption of new technologies. In the whole chain eggs incubation represents the origin of the process; as it is responsible of transforming biologically fertile eggs intone day old chicks. In the industrial scale incubator machines are used to reproduce natural bird's incubation conditions with the objective of increasing at its maximum the hatching index as well birth quality of the broilers. However, the embryonic development inside the eggs is substantially affected by the environmental conditions within the incubator. Embryos are not apt to control heat or mass exchanges during incubation; then, the main ambient variables which influence the process such as air temperature and relative humidity need to be adjusted with criterion, as maintaining the adequate conditions around the eggs is a critical control point of the process. Knowledge on the automation and control areas is able to positively influence incubator efficiency; then, the control system must warrant operational stability for the process conditions as well as its variables, within certain wanted limits. fuzzy control is the most adequate use for the processes which present non-linearity and transient behavior, since it describes in a routine the human experience for controlling the process. In this context it was proposed in the present study to develop an automation architecture composed by a fuzzy control system in order to provide more precise control of the variables that are of interest on incubation. The study was developed in two stages, being 1) and experimental trial of dynamic identification and mathematical modeling of an incubator of single stage; and 2) process simulation of eggs incubation. It was developed a computer model of the incubator built from the mathematical representation of the incubator, the interaction of the heat and mass transfer between the eggs and the environment, and by the fuzzy inference system used for controlling the incubation process. Simulation led to built up various incubators operational scenarios providing the adequate adjustment for the proposed control. It was found as main result the behavior of the following variables along the time: eggs' and ambient temperatures, eggs mass, air relative humidity, embryonic heat production, details of the eggs and ambient, and the studied incubators performing conditions. The obtained results related to eggs mass were below the expected, and for that the control system needs to be adjusted. Generally technical knowledge regarding incubation were achieved, and they may be useful for implementing a real control system. / Mestrado / Maquinas Agricolas / Mestre em Engenharia Agrícola