The effect of genotype and slaughter age on gonadal development, body development and the correlations between these measurements were studied in five pig genotypes (Genotype 1, Genotype 2, Genotype 3, Genotype 4 and Genotype 5) consisting of 112 gilts and 112 boars with initial live weights varying between 25 – 30 kg. The pigs were group-housed in commercial type grower houses and fed a diet consisting of 14 MJ/kg energy, 18 % CP and 1.1 % lysine during the growth period up to a live weight of 65 kg, followed by a diet consisting 13.5 MJ/kg, 16 % CP and 0.9% lysine from 65 kg to 90 kg and then a diet consisting of 13.2 MJ/kg, 15 % CP and 0.7% lysine from 90 kg onwards. Pigs were slaughtered at 116, 130, 144, 158, 172, 186, 200 and 214 days of age. Gonadal growth and development were measured in gilts (ovary length, ovary width, ovary thickness, ovary weight, ovary volume, follicle number, and size of the largest follicle), boars (testis length, testis width, testis weight and testis volume) and body development parameters (slaughter weight, warm carcass weight, carcass length, chest depth, dressing percentage and P2 backfat thickness) were compared. Differences between means were tested using breed, sex and slaughter age as fixed effects, while the relationships between gonadal and body development parameters were evaluated by means of correlation analysis. Genotype 5 had a significantly shorter ovary length than Genotype 4 and Genotype 2. Genotype 2 gilts also had heavier ovaries and larger ovary volumes than Genotype 5 gilts. In boars, Genotype 2 had significantly heavier testes weights than Genotype 5 boars. Genotype 5 boars also tended to have smaller testis volumes than Genotype 2 boars. In body development, Genotype 2 gilts and boars were superior to the Genotype 5 in terms of slaughter and warm carcass weights, while Genotype 3 seconded Genotype 2. The average P2 backfat thicknesses were 11.88 mm and 13.68 mm for boars and gilts respectively. Correlations between gonadal and body development parameters were low to moderate in the gilts (r = -0.305 to 0.555) and moderate to high in boars (r = 0.560 to 0.871). However, dressing percentage, follicle number and size of the largest follicle correlated poorly with all other measurements. It is concluded from the study that although Genotype 5 do not grow to the same size and at the same rate compared to the other genotypes, they appear to be the most suitable for the production of top quality pork in terms of its low backfat thickness. Genotype 5 pigs were also characterized with a slower gonadal growth and body development compared to Genotype 2 pigs. Results from this study suggest that selecting against backfat may delay gonadal development and sexual maturation in pigs. / Dissertation (MSc (Agric) Production Physiology)--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted

Os ouriços do mar são extremamente importantes no que diz respeito ao funcionamento do ecossistema marinho. Sua capacidade de estruturar este ambiente causa implicações em larga escala. Baseado nisso e tomando em conta que sua faixa de distribuição é bastante larga, esforços são necessários para uma melhor compreensão de sua ecologia. Neste trabalho buscou-se compreender como diâmetro, densidade populacional e desenvolvimento gonadal se apresentam em uma escala espaço-temporal. Foi feito também um estudo para entender como são compostas as comunidades do fitobentos associada ao ouriço e a sua dieta e, como estas composições se comportam entre tempos e locais diferentes. Por fim, foi realizado um estudo com índices de preferência alimentar a fim de identificar se estes ouriços exibem preferência ou rejeição para algum item alimentar e, da mesma maneira que feito anteriormente, verificar se a seletividade é heterogênea no tempo e no espaço. No período de aproximadamente um ano, foram analisadas populações e coletados 192 ouriços da espécie Lytechinus variegatus. Foi verificado que, em relação às densidades populacionais, parece existir um padrão espacial de crescimento dos animais de sudeste a noroeste da enseada de Parati-Mirim, sem a observação de um padrão temporal. Quanto ao diâmetro, os ouriços parecem ser menores no setor 2, a partir da segunda coleta até a quinta coleta os ouriços apresentam crescimento. Entre todos os setores, o desenvolvimento gonadal foi maior no setor 3, parece haver aumento do grau de desenvolvimento gonadal da segunda até a sexta coleta, mas sem padrão definido, apontando para o fato de que sempre existem ouriços com gônadas em diferentes graus de desenvolvimento. Quanto à composição do fitobentos, existe uma heterogeneidade espaço-temporal determinada por Sargassum, Jania e Padina. Entre estas três formações existe um gradiente de mudança na fisionomia dos setores. O mesmo não foi observado na composição da dieta, neste caso, a heterogeneidade espaço-temporal se deu principalmente devido a difusão da variabilidade desta composição, sem que existam grupos característicos determinando as diferenciações. Por fim, os resultados do índice de seletividade mostraram que apesar de ser conhecido como um generalista, L. variegatus exibe preferência por alguns gêneros de algas e rejeita outros. Em média não existem grandes variações espaço-temporais no comportamento de preferência e rejeição / Sea urchins are extremely important for the functioning of the marine ecosystem. Its capacity to structure this environment is causes implications on large scale. Based on that and considering that its distribution range is very wide, efforts for a better understanding of its ecology are necessary. On this study the aim was to comprehend how diameter, population density and gonadal development are presented on a spatial-temporal scale. A study to understand how phytobenthos communities and sea urchins diet are composed and how they behave in different places and sampling periods was conducted. At least, a study with a selective preference index was conducted in order to identify if these sea urchins exhibit preference or rejection for particular food items and, as before, verify if selection is heterogenous through sectors and sampling times. On the period studied, 192 Lytechinus variegates sea urchins were collected and analyzed. It was noted that, in relation to population densities, there seems to be a spatial growing pattern from the southeast to the northwest of Parati-Mirim inlet, with no recognition of a temporal pattern. As to urchins\' diameter, sea urchins seem smaller on sector 2, from the second to the fifth sampling period sea urchins increase in size. Among all sectors gonadal development was higher on sector 3, there seems to be an increase on the degree of gonadal development from the second to the sixth sampling period, although with no defined pattern, pointing to the fact that through time there are always urchins with gonads in different degrees of development. As to phytobenthos composition there is a spatial-temporal heterogeneity determined by Sargassum, Jania and Padina. Between these three formations there is a gradient of substrate change. The same pattern was not observed considering urchins diet, in this case, spatial-temporal heterogeneity occurred due to the grater variability of diet composition, with no defined groups determining these differences. At least, the results of the selective index showed that, even though considered a generalist, L. variegates exhibits preference for some algae genus and rejects others. In average there are no marked spatial-temporal variations on the behavior of preference and rejection

Resumo: O lambari Astyanax altiparanae Garutti e Britski (2000) vem ganhando a atenção de pesquisadores e produtores, devido a sua alta taxa de sobrevivência, rápido crescimento, fácil aceitação de alimento artificial, carne saborosa e grande procura como isca viva. As fêmeas apresentam taxas de crescimento mais elevadas do que os machos tornando sua criação mais vantajosa. O processo de diferenciação sexual pode ser controlado pela administração de hormônios sexuais, em peixes sexualmente indiferenciados, alterando o curso da diferenciação no sentido do sexo desejado. Neste trabalho, o desenvolvimento gonadal foi acompanhado nas primeiras 180 horas pós eclosão - hpe (7,5 dias pós eclosão - dpe) das larvas, na tentativa de se conhecer o momento da diferenciação sexual e/ou a melhor fase para aplicação de hormônio feminizante. Foram mantidas 1.000 larvas recémeclodidas em tanques de incubadoras sob aeração constante e temperatura ambiente. Dez exemplares foram diariamente fixados em solução Karnovsky modificada, incluídos em historesina, e corados com HE. Os resultados revelaram que as 12 hpe, o cordão gonadal já está alocado permanecendo por todo o período estudado. Durante o período inicial de aproximadamente 206ºC dias de vida da larva não observou-se, por meio de análise histológica, diferenciação sexual em A. altiparanae. Nesta fase foi possível observar, a abertura da boca que se deu às 19 hpe e a transição alimentar que ocorreu entre 43 e 60 hpe. Em um segundo estudo, a produção de lotes monossexos femininos do lambari foi avaliada, pelo método direto, utilizando o estrógeno, valerato de estradiol, na tentativa de provocar a feminização dos machos. Para isto, foram utilizadas 1.000 larvas de lambari que foram distribuídas em quatro tanques de incubadoras com temperatura média de 21.8 ± 2ºC... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The lambari Astyanax altiparanae Garutti and Britski (2000) has been getting attention of researchers and producers, due to its high rate of survival, fast growth, easy acceptance of food artificial, tasty meat and high demand as live bait. Females have higher growth rates than males making its creation more advantageous. The process of sexual differentiation can be controlled by administration of sex hormones in fish sexually undifferentiated, altering the course of differentiation towards the desired sex. In this study, the gonadal development was observed in the first 180 hours post-hatching - hph (7,5 days post-hatching - dph) of the larvae, in attempt to know the time of sexual differentiation and/or the best stage for the application of female hormone. 1.000 larvae, which were newly-hatched in tanks of incubators under constant aeration and ambient temperature, were kept. Ten specimens were daily fixed in solution Karnovsky modified, included in historesin, and stained with HE. The results showed that 12 hph, the gonadal cord is already allocated by remaining throughout the study period. During the initial period of, approximately, 206ºC-day life of the larva, it is not observed, by means of histological analysis, sexual differentiation in A. altiparanae. At this stage, it was possible to observe the opening of the mouth, which happened at 19 hph, and the food transition, which occurred between 43 and 60 hph. In a second study, the production of female monossex lots of lambari was evaluated by the direct method, using estrogen, estradiol valerate, in an attempt to cause the feminization of males. For this purpose, 1.000 lambari larvae, which had been distributed in four tanks of incubators, in an average temperature of 21.8 ± 2ºC, were used. Initially, the larvae were fed by nauplii of Artemia salina and, 72 hph, their food was replaced by a diet containing 35% crude protein... (Complete abstract click electronic access below) / Orientador: Patricia Pasquali Parise Maltempi / Coorientador: Carmem Silvia Fontanetti Christofoletti / Banca: Rosicleire Veríssimo Silveira / Banca: Yara Aiko Tabata / Mestre

Orientador: Rosicleire Veríssimo Silveira / Resumo: Peixes competem entre si em condições de escassez de recursos e por status em uma hierarquia de dominância. Os machos têm que superar potenciais rivais e o comportamento agressivo é a forma de alcançar esse objetivo, entretanto, isso introduz o risco de injúrias e pode levar a morte do animal. Diante disso, objetivou-se avaliar a influência da quantidade de fêmeas no desenvolvimento testicular e mortalidade dos machos de Astyanax altiparanae. Exemplares adultos, 248 machos e 72 fêmeas, foram submetidos a uma biometria inicial e final após 34 dias de experimento. O delineamento foi inteiramente casualizado com quatro tratamentos e quatro repetições, os tratamentos foram as proporções de: 0, 10, 30 e 50% fêmeas/machos. Foram analisados os dados biométricos, a mortalidade, o índice gonadossomático e as fases de maturação gonadal através da análise histológica em microscopia de luz. Os dados foram submetidos ao teste de análise de variância (ANOVA) a 5% de significância e as variáveis que sofreram efeito dos tratamentos foram submetidas ao teste t (LSD). O aumento na porcentagem de fêmeas nos tratamentos, levou a um aumento da mortalidade dos machos, como demonstrado em T0, T10 e T30, entretanto a relação de 1:1 macho/fêmea, influenciou na redução da agressividade e consequentemente na mortalidade dos peixes. Verificou-se que diferentes proporções de fêmeas não diferiram o IGS dos machos, e no tratamento com 50% de fêmeas foi possível ver uma continuidade da maturação testicular,... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fish compete with each other in conditions of scarcity of resources and for status in a hierarchy of dominance. Males have to overcome potential rivals and aggressive behavior is the way to achieve this goal; however, this introduces the risk of injury and can lead to the death of the animal. The objective of this study was to evaluate the influence of the number of females on the testicular development and mortality of the males of Astyanax altiparanae. Adults, being 248 males and 72 females were submitted to an initial and final biometry after 34 days of experiment. The experimental design was completely randomized with four treatments and four replications, the treatments being the proportions of: 0, 10, 30 and 50% females/males. Biometric data, mortality, gonadosomatic index and gonadal maturation phases were analyzed through histological analysis under light microscopy. Data were submitted to the analysis of variance (ANOVA) at 5% of significance and the variables that underwent treatment effects were submitted to the t test (LSD). The increase in the percentage of females in the treatments led to an increase in the mortality of males, as demonstrated in T0, T10 and T30; however the ratio 1:1 male/female, influenced the reduction of aggressiveness and consequently mortality. It was verified that different proportions of females did not differ the IGS, and in the treatment with 50% of females it was possible to see a continuity of testicular maturation, showing that there... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:23:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-07Bitstream added on 2014-06-13T19:49:29Z : No. of bitstreams: 1 bem_jc_me_rcla.pdf: 669449 bytes, checksum: 0288c0d763b074ddbb25c517c036ec04 (MD5) / O lambari Astyanax altiparanae Garutti e Britski (2000) vem ganhando a atenção de pesquisadores e produtores, devido a sua alta taxa de sobrevivência, rápido crescimento, fácil aceitação de alimento artificial, carne saborosa e grande procura como isca viva. As fêmeas apresentam taxas de crescimento mais elevadas do que os machos tornando sua criação mais vantajosa. O processo de diferenciação sexual pode ser controlado pela administração de hormônios sexuais, em peixes sexualmente indiferenciados, alterando o curso da diferenciação no sentido do sexo desejado. Neste trabalho, o desenvolvimento gonadal foi acompanhado nas primeiras 180 horas pós eclosão – hpe (7,5 dias pós eclosão - dpe) das larvas, na tentativa de se conhecer o momento da diferenciação sexual e/ou a melhor fase para aplicação de hormônio feminizante. Foram mantidas 1.000 larvas recémeclodidas em tanques de incubadoras sob aeração constante e temperatura ambiente. Dez exemplares foram diariamente fixados em solução Karnovsky modificada, incluídos em historesina, e corados com HE. Os resultados revelaram que as 12 hpe, o cordão gonadal já está alocado permanecendo por todo o período estudado. Durante o período inicial de aproximadamente 206ºC dias de vida da larva não observou-se, por meio de análise histológica, diferenciação sexual em A. altiparanae. Nesta fase foi possível observar, a abertura da boca que se deu às 19 hpe e a transição alimentar que ocorreu entre 43 e 60 hpe. Em um segundo estudo, a produção de lotes monossexos femininos do lambari foi avaliada, pelo método direto, utilizando o estrógeno, valerato de estradiol, na tentativa de provocar a feminização dos machos. Para isto, foram utilizadas 1.000 larvas de lambari que foram distribuídas em quatro tanques de incubadoras com temperatura média de 21.8 ± 2ºC... / The lambari Astyanax altiparanae Garutti and Britski (2000) has been getting attention of researchers and producers, due to its high rate of survival, fast growth, easy acceptance of food artificial, tasty meat and high demand as live bait. Females have higher growth rates than males making its creation more advantageous. The process of sexual differentiation can be controlled by administration of sex hormones in fish sexually undifferentiated, altering the course of differentiation towards the desired sex. In this study, the gonadal development was observed in the first 180 hours post-hatching – hph (7,5 days post-hatching - dph) of the larvae, in attempt to know the time of sexual differentiation and/or the best stage for the application of female hormone. 1.000 larvae, which were newly-hatched in tanks of incubators under constant aeration and ambient temperature, were kept. Ten specimens were daily fixed in solution Karnovsky modified, included in historesin, and stained with HE. The results showed that 12 hph, the gonadal cord is already allocated by remaining throughout the study period. During the initial period of, approximately, 206ºC-day life of the larva, it is not observed, by means of histological analysis, sexual differentiation in A. altiparanae. At this stage, it was possible to observe the opening of the mouth, which happened at 19 hph, and the food transition, which occurred between 43 and 60 hph. In a second study, the production of female monossex lots of lambari was evaluated by the direct method, using estrogen, estradiol valerate, in an attempt to cause the feminization of males. For this purpose, 1.000 lambari larvae, which had been distributed in four tanks of incubators, in an average temperature of 21.8 ± 2ºC, were used. Initially, the larvae were fed by nauplii of Artemia salina and, 72 hph, their food was replaced by a diet containing 35% crude protein... (Complete abstract click electronic access below)

Submitted by ELIS MARINA DA SILVA CABRAL (elismarina989@gmail.com) on 2018-05-09T14:46:30Z No. of bitstreams: 1 Dissertação final_Elis Marina.pdf: 1978717 bytes, checksum: 9d56daa81d3c96634c39042f06952046 (MD5) / Approved for entry into archive by Cristina Alexandra de Godoy null (cristina@adm.feis.unesp.br) on 2018-05-09T17:34:56Z (GMT) No. of bitstreams: 1 cabral_ems_me_ilha.pdf: 1978717 bytes, checksum: 9d56daa81d3c96634c39042f06952046 (MD5) / Made available in DSpace on 2018-05-09T17:34:56Z (GMT). No. of bitstreams: 1 cabral_ems_me_ilha.pdf: 1978717 bytes, checksum: 9d56daa81d3c96634c39042f06952046 (MD5) Previous issue date: 2018-03-07 / Peixes competem entre si em condições de escassez de recursos e por status em uma hierarquia de dominância. Os machos têm que superar potenciais rivais e o comportamento agressivo é a forma de alcançar esse objetivo, entretanto, isso introduz o risco de injúrias e pode levar a morte do animal. Diante disso, objetivou-se avaliar a influência da quantidade de fêmeas no desenvolvimento testicular e mortalidade dos machos de Astyanax altiparanae. Exemplares adultos, 248 machos e 72 fêmeas, foram submetidos a uma biometria inicial e final após 34 dias de experimento. O delineamento foi inteiramente casualizado com quatro tratamentos e quatro repetições, os tratamentos foram as proporções de: 0, 10, 30 e 50% fêmeas/machos. Foram analisados os dados biométricos, a mortalidade, o índice gonadossomático e as fases de maturação gonadal através da análise histológica em microscopia de luz. Os dados foram submetidos ao teste de análise de variância (ANOVA) a 5% de significância e as variáveis que sofreram efeito dos tratamentos foram submetidas ao teste t (LSD). O aumento na porcentagem de fêmeas nos tratamentos, levou a um aumento da mortalidade dos machos, como demonstrado em T0, T10 e T30, entretanto a relação de 1:1 macho/fêmea, influenciou na redução da agressividade e consequentemente na mortalidade dos peixes. Verificou-se que diferentes proporções de fêmeas não diferiram o IGS dos machos, e no tratamento com 50% de fêmeas foi possível ver uma continuidade da maturação testicular, mostrando que não houve alterações no desenvolvimento dos testículos. Conclui-se que, o cultivo em grupos mistos, na proporção de 1:1, é, benéfico para esta espécie. / Fish compete with each other in conditions of scarcity of resources and for status in a hierarchy of dominance. Males have to overcome potential rivals and aggressive behavior is the way to achieve this goal; however, this introduces the risk of injury and can lead to the death of the animal. The objective of this study was to evaluate the influence of the number of females on the testicular development and mortality of the males of Astyanax altiparanae. Adults, being 248 males and 72 females were submitted to an initial and final biometry after 34 days of experiment. The experimental design was completely randomized with four treatments and four replications, the treatments being the proportions of: 0, 10, 30 and 50% females/males. Biometric data, mortality, gonadosomatic index and gonadal maturation phases were analyzed through histological analysis under light microscopy. Data were submitted to the analysis of variance (ANOVA) at 5% of significance and the variables that underwent treatment effects were submitted to the t test (LSD). The increase in the percentage of females in the treatments led to an increase in the mortality of males, as demonstrated in T0, T10 and T30; however the ratio 1:1 male/female, influenced the reduction of aggressiveness and consequently mortality. It was verified that different proportions of females did not differ the IGS, and in the treatment with 50% of females it was possible to see a continuity of testicular maturation, showing that there were no alterations in the development of testicles. In conclusion, the cultivation in mixed groups in the proportion of 1:1 is beneficial for this species.

Os ouriços do mar são extremamente importantes no que diz respeito ao funcionamento do ecossistema marinho. Sua capacidade de estruturar este ambiente causa implicações em larga escala. Baseado nisso e tomando em conta que sua faixa de distribuição é bastante larga, esforços são necessários para uma melhor compreensão de sua ecologia. Neste trabalho buscou-se compreender como diâmetro, densidade populacional e desenvolvimento gonadal se apresentam em uma escala espaço-temporal. Foi feito também um estudo para entender como são compostas as comunidades do fitobentos associada ao ouriço e a sua dieta e, como estas composições se comportam entre tempos e locais diferentes. Por fim, foi realizado um estudo com índices de preferência alimentar a fim de identificar se estes ouriços exibem preferência ou rejeição para algum item alimentar e, da mesma maneira que feito anteriormente, verificar se a seletividade é heterogênea no tempo e no espaço. No período de aproximadamente um ano, foram analisadas populações e coletados 192 ouriços da espécie Lytechinus variegatus. Foi verificado que, em relação às densidades populacionais, parece existir um padrão espacial de crescimento dos animais de sudeste a noroeste da enseada de Parati-Mirim, sem a observação de um padrão temporal. Quanto ao diâmetro, os ouriços parecem ser menores no setor 2, a partir da segunda coleta até a quinta coleta os ouriços apresentam crescimento. Entre todos os setores, o desenvolvimento gonadal foi maior no setor 3, parece haver aumento do grau de desenvolvimento gonadal da segunda até a sexta coleta, mas sem padrão definido, apontando para o fato de que sempre existem ouriços com gônadas em diferentes graus de desenvolvimento. Quanto à composição do fitobentos, existe uma heterogeneidade espaço-temporal determinada por Sargassum, Jania e Padina. Entre estas três formações existe um gradiente de mudança na fisionomia dos setores. O mesmo não foi observado na composição da dieta, neste caso, a heterogeneidade espaço-temporal se deu principalmente devido a difusão da variabilidade desta composição, sem que existam grupos característicos determinando as diferenciações. Por fim, os resultados do índice de seletividade mostraram que apesar de ser conhecido como um generalista, L. variegatus exibe preferência por alguns gêneros de algas e rejeita outros. Em média não existem grandes variações espaço-temporais no comportamento de preferência e rejeição / Sea urchins are extremely important for the functioning of the marine ecosystem. Its capacity to structure this environment is causes implications on large scale. Based on that and considering that its distribution range is very wide, efforts for a better understanding of its ecology are necessary. On this study the aim was to comprehend how diameter, population density and gonadal development are presented on a spatial-temporal scale. A study to understand how phytobenthos communities and sea urchins diet are composed and how they behave in different places and sampling periods was conducted. At least, a study with a selective preference index was conducted in order to identify if these sea urchins exhibit preference or rejection for particular food items and, as before, verify if selection is heterogenous through sectors and sampling times. On the period studied, 192 Lytechinus variegates sea urchins were collected and analyzed. It was noted that, in relation to population densities, there seems to be a spatial growing pattern from the southeast to the northwest of Parati-Mirim inlet, with no recognition of a temporal pattern. As to urchins\' diameter, sea urchins seem smaller on sector 2, from the second to the fifth sampling period sea urchins increase in size. Among all sectors gonadal development was higher on sector 3, there seems to be an increase on the degree of gonadal development from the second to the sixth sampling period, although with no defined pattern, pointing to the fact that through time there are always urchins with gonads in different degrees of development. As to phytobenthos composition there is a spatial-temporal heterogeneity determined by Sargassum, Jania and Padina. Between these three formations there is a gradient of substrate change. The same pattern was not observed considering urchins diet, in this case, spatial-temporal heterogeneity occurred due to the grater variability of diet composition, with no defined groups determining these differences. At least, the results of the selective index showed that, even though considered a generalist, L. variegates exhibits preference for some algae genus and rejects others. In average there are no marked spatial-temporal variations on the behavior of preference and rejection

Keimzellen entwickeln sich aus den sogenannten Urkeimzellen, die auch als primordiale Keimzellen (PGC) bezeichnet werden. PGC entwickeln sich während der Embryonalentwicklung und wandern dann in die Gonadenanlagen, wo sie sich vermehren und bei getrenntgeschlechtlichen Arten in Spermien in Männchen und Oozyten bei Weibchen differenzieren. Während der Geschlechtsdifferenzierung sind die Gonaden anfällig für den Einfluss externer Faktoren, wie z. B. der Wassertemperatur. Eine Erhöhung der Wassertemperatur von 28°C auf 36°C während der kritischen Phase der Geschlechtsdifferenzierung, vom 10. bis zum 20. Tag nach der Befruchtung kann zu einer Vermännlichung genetisch-weiblicher Tilapien führen. In der ersten Studie führte eine entsprechende Temperaturbehandlung bei genetisch weiblichen Tilapien zu einem Anteil funktioneller Männchen von 37%. Makromorphologisch konnten die Gonaden 90 Tage alter Weibchen aus Kontroll- und Behandlungsgruppen als unreife Ovarien klassifiziert werden. Erste Reifungsprozesse bis hin zur Oogenese begannen 120 Tage nach der Befruchtung. Die Oogenese konnte mikro-morphologisch weiterhin in folgende Stadien eingeteilt werden: Chromatin Nukleolus, Peri-Nukleolus, kortikale Alveolus, Vitellogenese und reife Eizelle. Oozyten in den Phasen des Chromatin Nukleolus und des Peri-Nukleolus, welche auch die primäre Wachstumsphase darstellen, wurden bei weiblichen Fischen aller Altersgruppen festgestellt. Während weiter fortgeschrittenen Oozytenstadien erst ab einem Alter von 120 Tagen festgestellt werden konnten. Oozyten in der Phase des kortikalen Alveolus wurden demnach frühestens am 120. Lebenstag gefunden. In der Vitellogenese befindliche Oozyten traten erst nach 150 Tagen auf. Reife Eizellen wurden ab einem Alter von 180 dpf festgestellt. Es konnten keine signifikanten Unterschiede in der Eizellentwicklungsstadien zwischen Kontroll- und Behandlungstieren festgestellt werden. Das Ziel der zweiten Studie war die Identifikation von Keimbahn-Stammzellen bei Tilapien, die während der Geschlechtsdifferenzierung verschiedenen Aufzuchttemperaturen ausgesetzt waren. Die Identifizierung der Keimbahn-Stammzellen erfolgte anhand von Immunohistochemie mittels Vasa und PCNA (Proliferierendes Cell Nuclear Antigen) Antikörperfärbung. Es wurden zunächst histologische Schnitte von in Paraffin eingebettetem Ovargewebe hergestellt. Keimbahn-Stammzellen wurden im Keimepithel der Ovarien identifiziert, wobei diese in einzelner, isolierter oder in Clusterform vorlagen. Keimbahn-Stammzellen wurden sowohl bei weiblichen Tieren aus Kontroll- als auch Behandlungsgruppen identifiziert. Zusammenfassend, konnten erstmalig Keimbahn-Stammzellen und ihre Lage in den Gonaden genetisch weiblicher Tilapien, aus Kontroll- und Behandlungsgruppen, mittels Vasa und PCNA Antikörperfärbung charakterisiert werden.

Les anomalies du développement sexuel recouvrent un spectre phénotypique large. Les hommes XX présentent dans la majorité des cas un développement testiculaire normal, lié à la présence SRY sur un des chromosomes X. Dans 10% des cas, aucune cause n’est retrouvée. Chez les femmes, l’origine de l’insuffisance ovarienne prématurée (IOP) n’est identifiée que dans 20% des cas. L’objectif de cette thèse a été d’identifier de nouveaux mécanismes moléculaires impliqués dans le développement gonadique, testiculaire et ovarien, ainsi que dans son fonctionnement. L’étude d’une cohorte de patients DSD 46,XX SRY négatifs a mis en évidence une duplication de la région RevSex dans un désert génique en amont de SOX9 chez quatre patients. Ceci a permis de redéfinir la région minimale impliquée dans l'activation de l'expression de SOX9 à une taille maximale de 41.9 kb et de proposer un mécanisme permettant cette expression chez des hommes XX. Le séquençage d’exome chez dix patients de la cohorte n’a pas mis en évidence de mutations dans des gènes d’intérêts. L’ensemble de ces résultats pose la question du rôle des régions régulatrices dans la survenue des DSD.L’analyse d’une cohorte de patientes ayant une IOP a permis d'identifier des délétions incluant le gène CPEB1. Des études précédentes chez la souris ont montré son implication dans le développement folliculaire. Le séquençage du gène CPEB1 dans la cohorte n'a pas mis en évidence de mutation pathogène. Ce travail a permis de montrer que la délétion impliquant le gène CPEB1est une cause rare mais récurrente d'IOP et concerne environ 1% des patientes. Une microdélétion contenant le gène CASP3 un gène de la voie des caspases impliquée dans la régulation du pool folliculaire a également été identifiée chez une patiente. L'ensemble de ces résultats montre l'intérêt de l'étude génétique des patients présentant une anomalie du développement de la gonade ou de son fonctionnement par des techniques d'étude globale du génome. / Disorders of Sex Development (DSD) can be identified in new-born and during infancy but also in adults because of infertility. Most 46,XX testicular DSD have a normal testicular development due to the presence of the SRY gene at the tip of one of their X chromosome. However, the genetic causes of 46,XX-SRY negative testicular DSD remain poorly defined. In women, disorders of gonadal development can be responsible for primary ovarian insufficiency (POI) and genetic causes are identify in only 20% of cases. The aim of this thesis was to identify molecular mechanisms involved in gonadal development and in its functioning. The cohort study of 46,XX testicular DSD identified four patients with a duplication in the previously reported RevSex region located about 550 kb upstream of SOX9. One duplication allowed us to refine the minimal region associated with 46,XX-SRY negative DSD to a 40.7–41.9 kb element. Exome sequencing of 10 patients from the cohort did not show any mutation in genes implicated in DSD or in new candidate genes. These results raise questions about the role of the regulatory sequences in the onset of DSD.The cohort study of POI patients identified three patients carrying a microdeletion including CPEB1 a good candidate gene for POI as study in mice showed the implication of CPEB1 in follicular development. Sequencing CPEB1 gene did not identified any mutation. Therefore, heterozygous deletion of CPEB1 gene leading to haploinsufficiency could be responsible for POI in humans. This microdeletion is rare but recurrent and was identified in about 1% of patients with POI. Another microdeletion containing CASP3 gene that belongs to the caspase family, which is implicated in the regulation of the follicular pool, was identified in a patient. Further studies are needed to confirm the role of CASP3 in POI. These results demonstrate the importance of genetic study of patients presenting with DSD or POI using whole genome techniques.

Chez les mammifères, la détermination du sexe est un processus moléculaire complexe impliquant une balance de gènes finement régulée entre la voie mâle et femelle. La formation de testicules est initiée par SRY en synergie avec SF1 par sur-activation de l'expression de SOX9 au delà d'un seuil critique, ce qui entraîne l'activation du programme de la voie mâle et la répression de la développement ovarien. Des erreurs dans ce processus peuvent entraîner des pathologies de dysgénésie gonadique (DSD). Bien que de nombreux gènes impliqués dans le développement des gonades, sont à présent identifiés, les mutations de ces gènes n'expliquent qu'une minorité de cas de DSD, et les mécanismes conduisant à un développement sexuel inapproprié restent encore largement méconnus.Nous avons identifié, pour la première fois, une mutation ponctuelle dans le gène DMRT1 humain, facteur crucial de la détermination du sexe chez différentes espèces, associée à une absence de développement testiculaire. Une série d'analyses fonctionnelles démontrent le mécanisme par lequel cette mutation pourrait être lie à un DSD et que, différemment de chez la souris, DMRT1 humain, est impliqué dans la détermination testiculaire primaire.Le séquençage d’exomes sur des patients présentant un DSD de type 46,XY ont permis d’identifier des mutations délétères chez SOX7 & SOX8, suggérant une possible redondance fonctionnelle parmi les gènes SOX dans la détermination du sexe; mais également des mutations chez GATA4 établissant un rôle pour ce gène comme cause de DSD. Nos résultats d’analyses fonctionnelles indiquent des changements dans l'activité biologique des protéines mutées, mais dans certains cas, ne révèlent pas les mécanismes impliqués dans l’apparition de DSD. Par conséquent, le développement de nouveaux modèles cellulaires in-vitro pourrait permettre d’élucider ces mécanismes. Notamment, l’utilisation de cellules souches embryonnaires de souris, nous permettra de développer un nouveau modèle cellulaire pour mieux comprendre l'effet biologique de ces mutations. / In mammals, sex determination and development is a complex process that involves genetic networks acting synergistically or antagonistically. Testis formation is initiated by SRY+SF1 up-regulation of SOX9 expression beyond a critical level, resulting in the activation of male-specific program and ovaries repression. In females, SRY absence results in the activation of ovarian development and testis repression. Errors in the process result in gonadal dysgenesis (DSD). Although, we begin to know the genes involved in gonad development, mutations in these genes explain only few DSD cases, and the mechanism leading to abnormal sexual development remain misunderstood. DMRT1 regulates sex-determination in different species. Its role in mammalian sex-determination is unclear. We identified the first point mutation in human DMRT1 associated with a lack of testis-determination. Functional analyses revealed the mechanism by which this mutation could lead to DSD. Showing that, differently to mouse, human DMRT1 is involved in primary testis-determination and that at molecular level sex-determination a very conserved process. Further studies using exome sequencing on patients with 46,XY DSD identify pathogenic mutations in 2 SOX genes: SOX7 & SOX8. Suggesting a possible functional redundancy amongst SOX genes in sex-determination. We identified mutations in GATA4 associated with 46,XY DSD, establishing a role for this gene as a DSD cause. The functional consequences of these mutations on their biological activity were assessed using classical approaches. Our results indicate changes in biological activity of the mutated proteins but in some cases don’t reveal the mechanisms involved in DSD. Therefore, the development of novel in-situ cellular models may provide a tool to identify these mechanisms. Using mouse embryonic stem cells we’re developing novel cellular models to understand the biological effect of these mutations in the appropriate environment.