La maturation sexuelle se fait en réponse à l'intégration de divers signaux internes homéostatiques et externes. Jusqu'à présent, on ignore en grande partie quels mécanismes sensoriels internes sont impliqués dans le couplage de ces signaux. Chez les mammifères, le début de la puberté est associé à des pulsations élevées de GnRH conduisant à un pic d'hormone stéroïdienne. Le système ligand/récepteur, KISS/KISSR, est un régulateur en amont des neurones producteurs de GnRH. Chez Drosophila melanogaster, un pic d'hormone prothoracicotrope (PTTH) produite par deux paires de neurones (PTTHn) conduit à la production de l'ecdysone, la principale hormone stéroïdienne chez les insectes. PTTH est l'un des premiers signaux à activer la cascade d'événements menant à la maturation. Si la production de PTTH est bloquée, un retard dans le début de la transition du stade juvénile au stade adulte est observé, tandis qu'une maturation précoce est observée lors de la surexpression de PTTH. Ceci indique donc un rôle important des PTTHn dans l'intégration des signaux. Afin de découvrir les signaux intégrés par les PTTHn, nous avons criblé une collection d’ARN interférents dans les PTTHn. Nous avons ainsi identifié le récepteur à l’allatostatine A (AstA-R1) comme un régulateur positif des PTTHn. La perte de fonction de AstA-R1 retarde la maturation avec une augmentation de la taille finale de l’organisme. Une réduction de la quantité du ligand allatostatine A (AstA) a également une incidence sur le déclenchement de la maturation. AstA est produite dans le cerveau par une paire de neurones bilatéraux qui étendent leurs axones vers les dendrites des PTTHn. De plus, les neurones AstA projettent également leurs axones vers les cellules productrices d’insuline (IPCs), connues pour réguler le taux de croissance larvaire. L’inactivation d’AstA-R1 dans les IPCs donne des organismes plus petits. Nos résultats impliquent que les neurones AstA sont capables de réguler le rythme de croissance ainsi que le déclenchement de la maturation en jouant sur deux circuits différents ciblant les PTTHn et les IPCs. De façon intéressante, AstA/AstAR1 est homologue à KISS/KISSR (GPR54), un facteur d’entrée dans de la puberté humaine. Ceci suggère donc qu’un circuit neuronal est conservé au cours de l’évolution pour l'intégration des signaux qui contrôlent le déclenchement de la maturation sexuelle. / The onset of puberty occurs in response to the integration of various internal homeostatic and external signals. Up until now, it remains largely unknown which internal sensory mechanisms are involved in the coupling of those signals. In mammals, the onset of puberty is associated with elevated GnRH pulsations leading to a peak of steroid hormones. The KISS/KISSR system is a pivotal upstream regulator of GnRH producing neurons. In Drosophila melanogaster a peak of prothoracicotropic hormone (PTTH) produced by two pairs of neurons (PTTHn) leads to the production of the insect steroid hormone ecdysone. PTTH is one of the first signals to activate the cascade of events leading to maturation. Once PTTH production is blocked, a delay is observed in the onset of the transition from juvenile to adult stage, whereas precocious maturation is observed upon PTTH over-expression, denoting an important role for PTTHn in the integration of cues. In order to uncover signals integrated by PTTHn we have conducted a biased RNAi screen in PTTHn. After two rounds of screening we identified the GPCR Allatostatin A receptor 1 (AstA-R1) as a positive regulator of PTTHn. AstA-R1 knock down delays maturation with a subsequent increase in final pupal size. Down regulation of its ligand, Allatostatin-A (AstA) on the brain is also affecting the timing of maturation. We found that AstA is produced in the central brain by a bilateral pair of neurons that extend their axons towards the PTTHn dendrites. In addition, AstA neurons also project their axons towards the Drosophila insulin producing cells (IPCs) that are known to regulate larval growth. Knockdown of AstA-R1 on the IPCs leads to smaller pupae. These findings imply that the AstA neurons are able to regulate growth and maturation timing by interacting with 2 different circuits: the PTTHn and IPCs. Unexpectedly, AstA-R1 and AstA genes share a common evolutionary origin with KISSR and KISS, respectively, suggesting a common mechanism between insects and mammals for the integration of signals that control the onset of puberty.

付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院 / 京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22634号 / 理博第4623号 / 新制||理||1664(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 古市 剛史, 教授 湯本 貴和, 教授 濱田 穣 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

O aumento da obesidade infantil tem sido correlacionado com a prevalência da puberdade precoce. Em animais pré-puberes verifica-se que a administração da dieta hiperlipídica induz a antecipação da puberdade. Estudos sugerem que a leptina pode influenciar o eixo reprodutivo por meio de sua ação em neurônios que expressam kisspeptina, no hipotálamo. Uma subpopulação de neurônios kisspeptidérgicos do núcleo arqueado coexpressa a dinorfina e neuroquinina B, que exercem uma ação autorreguladora sobre a secreção de kisspeptina. Considerando que a leptina, a kisspeptina, neuroquinina B e dinorfina são apontados como reguladores do início da puberdade e da função reprodutiva, este trabalho investigou como a dieta hiperlípidica (HFD) pode influenciar esses moduladores ao longo do início do desenvolvimento puberal e após a maturação sexual. Camundongos fêmeas Kiss1-hrGFP foram tratadas com a HFD ou dieta controle a partir do desmame e foram decapitadas aos 28, 32 e 63 dias (Diestro II) e o sangue coletado para dosagem plasmática de leptina, LH e estradiol. Um segundo grupo de fêmeas, tratadas com HFD ou dieta controle, receberam com 32 e 63 dias (Diestro I) uma injeção intraperitoneal de leptina (0,5 mg/kg) ou de veículo, 45 minutos após a injeção foram anestesiadas e submetidas à perfusão cerebral. Cortes hipotalâmicos foram utilizados para realização da técnica de imunoistoquímica para dupla marcação: Kiss1-p-STAT3/ p-STAT3-CART/ Kiss1-Dyn e Kiss1-NKB. Verificamos que a HFD administrada após o desmame, quando comparada à dieta controle, antecipou a abertura vaginal, o primeiro estro e o ínicio da ciclicidade em fêmeas Kiss1-hrGFP. Como indicativo de ativação do eixo reprodutivo neste grupo, foi observado aumento do peso do útero e ovário, aos 32 dias. Esses efeitos estiveram associados com: a) o aumento da concentração plasmática de leptina; b) aumento da ativação de p-STAT3 no núcleo arqueado (ARC) e c) aumento de p-STAT3 em neurônios Kiss1-hrGFP e em neurônios CART do ARC em resposta ao estímulo da leptina. A HFD não afetou a colocalização entre Kiss1-Dyn e Kiss1-NKB em fêmeas no início do desenvolvimento puberal. Em fêmeas Kiss1-hrGFP (63 dias) a administração da HFD por 6 semanas não alterou a regularidade do ciclo estral, houve elevação da leptina plasmática associada com diminuição da expressão da p-STAT3 no ARC em resposta ao estímulo com leptina, sem alterar a responsividade dos neurônios Kiss1-hrGFP a este hormônio. Em conclusão, 9 os resultados demonstram que a antecipação da puberdade induzida pela HFD está associada com o aumento da ação central da leptina, que ao estimular o sistema kisspeptidérgico, direta ou indiretamente, por meio de neurônios CART, pode aumentar o tônus excitatório sobre o eixo reprodutivo. A administração da HFD após o desmame (6 semanas) promoveu uma redução à resposta da leptina no ARC na vida adulta, porém não afetou a responsividade dos neurônios Kiss1-hrGFP a este hormônio e nem a regularidade do ciclo estral nas fêmeas Kiss1-hrGFP. Em conjunto, esses resultados indicam que as ações da leptina nesses neurônios foram preservadas, mesmo com a resistência parcial de suas ações no ARC. Estudos adicionais deverão ser realizados para se avaliar os efeitos a longo prazo da HFD sobre o eixo reprodutivo. / The increase of childhood obesity has been correlated with the early onset of puberty. In prepubertal animals it appears high fat diet (HFD) induces anticipation of puberty. Several studies have indicated that the effect of leptin on reproductive axis can be mediated by its action on Kiss1 neurons in the hypothalamus.A subpopulation of Kiss1 neurons in the arcuate nucleus also shows co-expression of neurokinin B and dynorphin A,presenting a self-regulatory action kisspeptin secretion. Since leptin, kisspeptin, neurokinin B and dynorphin are identified as regulators of puberty onset and reproductive function, this study investigated the influence of high fat diet on these modulators along puberty onset and after sexual maturation. A group of Kiss1-hrGFP-female mice received the HFD or regular chow after weaning. The Kiss1-hrGFP females were decapitated at 28, 32 and 63 days old (Diestrus II) and blood was collected for measurement of plasma leptin, LH and estradiol. A second group of females, treated with HFD or chow after weaning, received at 32 and 63 days old (Diestrus I) an intraperitoneal injection of leptin (0.5 mg / kg) or vehicle, and 45 minutes after they were anesthetized and subjected to cerebral perfusion. Immunohistochemistry was performed for double labeling: Kiss1-p-STAT3/ p-STAT3-CART/ Kiss1-Dyn and Kiss1-NKB in the hypothalamus. It was found that, compared to controls; the HFD anticipated the vaginal opening, the first estrus and the beginning of cyclicity in Kiss1-hrGFP females. An increase in the uterine weight and ovaries, confirmed the activation of reproductive axis in the HFD group at 32 days old. These effects were associated with: a) an increase in plasma leptin concentration; b) the activation of p-STAT3 in the arcuate nucleus (ARC) and c) the increase of p-STAT3 in Kiss1-hrGFP neurons and in CART neurons of the ARC in response to the stimulus of leptin. HFD didnt affect colocalization between Kiss1-Dyn and Kiss1-NKB in females mice at hte pubertal onset . Kiss1-hrGFP female mice (63 days old), exposed to HFD for 6 weeks,exhibited regular estrous cycles, increased plasma levels of leptin associated with a decreased p-STAT3 expression in the ARC after leptin stimulation, with no changes in the responsiveness of Kiss1-hrGFP neurons to this hormone, compared to controls. In conclusion, 11 the results demonstrate that the early puberty induced by the HFD is associated with increased central leptin action, by stimulating the kisspeptidergic system, directly or indirectly, through CART neurons that can increase the excitatory tone in the reproductive axis. The administration of HFD after weaning (6 weeks) induced a decrease on the response to leptin in the ARC in adulthood, but without changes in the responsiveness of Kiss1-hrGFP neurons to this hormone and the regularity of the estrous cycle in Kiss1-hrGFP females. Taken together, these results indicate that the actions of leptin in kisspeptin neurons were preserved after 6 weeks of HFD, despite the partial resistance to this hormone in the ARC. Additional studies should be conducted to evaluate the long-term effects of HFD in the reproductive axis.

Made available in DSpace on 2015-04-17T14:55:32Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3402064 bytes, checksum: 85b25b7cb2762709c6ff9c0a515b3170 (MD5) Previous issue date: 2012-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Camara beach is located in an Amazonian estuary in Pará State, northern Brazil, where fishing is a traditional activity and there is capture of several species of rays. The longnose stingray, Dasyatis guttata, is the most common in the catches, and as regional information on its biology is scarce, this study aimed to investigate aspects of reproductive biology of D. guttata and to determine its reproductive cycle in this area. Monthly samplings were performed from April 2011 to March 2012, through monitoring of artisanal fisheries with longline and trapping fence barriers ( currais ). A total of 81 specimens of D. guttata were collected, and the class with the largest number of individuals sampled was 100-200 mm disc width (DW), comprised of neonates and young. The presence of neonates observed throughout the year indicates Camara beach as a primary nursery area for this species. The presence of males is restricted to few months of the year and indicates a tendency to sexual segregation. The monthly variation in the abundance of individuals of D. guttata followed the variation of temperature and salinity number of specimens, suggesting seasonal migration. The disc width class in which 50% of females mature was estimated as 600-650 mm LD, and as 401-500 mm LD, for males. The largest male presented 635 mm DW and the largest female, 1130 mm DW. Dasyatis guttata females have only the left side of the reproductive system functional and the vitellogenesis occurs concomitantly with pregnancy. The average fertility is two uterine embryos and the estimated size at birth is 130 mm DW. The results suggest that individuals reproduce all year, with two reproduction peaks and a gestation of four months. These data should be considered in management plans and conservation of D. guttata. / A praia de Camará localiza-se em uma região estuarina amazônica, no estado do Pará, norte do Brasil, onde a pesca artesanal é uma atividade tradicional e captura várias espécies de raias. A raia bicuda, Dasyatis guttata, é a mais comum nas capturas, e, como as informações regionais sobre sua biologia são escassas, o presente estudo teve como objetivos investigar aspectos da biologia reprodutiva de espécie e determinar seu ciclo reprodutivo nesta área. Amostragens mensais foram efetuadas durante o período de abril de 2011 a março de 2012, por meio do acompanhamento da pesca artesanal de curral e espinhel. Um total de 81 exemplares de D. guttata foi coletado, e a classe com maior número de indivíduos amostrados foi de 100 200 mm de largura de disco (LD), composta por neonatos e jovens. A presença de neonatos ao longo do ano aponta Camará como uma região de berçário primário para esta espécie. A presença de machos observada em poucos meses do ano possivelmente indica uma tendência à segregação sexual. A variação mensal da abundância de indivíduos de D. guttata acompanhou as variações de temperatura e salinidade, o que sugere a ocorrência de migração sazonal. A classe de tamanho em que se estimou 50% de fêmeas maturas é a de 600 650 mm LD, e a de 401 500 mm LD, para os machos. O maior macho apresentou 635 mm LD e a maior fêmea, 1.130 mm LD. As fêmeas de D. guttata possuem somente o lado esquerdo do sistema reprodutivo funcional e apresentam vitelogênese concomitante à gestação. A fecundidade uterina uterina é de dois embriões e o tamanho estimado dos indivíduos ao nascer é de 130 mm LD. Os resultados sugerem que os indivíduos reproduzem-se ao longo do ano inteiro, com dois picos de reprodução e gestação de quatro meses. Esses dados devem ser considerados nos planos de manejo e conservação da espécie D. guttata.

O aumento da obesidade infantil tem sido correlacionado com a prevalência da puberdade precoce. Em animais pré-puberes verifica-se que a administração da dieta hiperlipídica induz a antecipação da puberdade. Estudos sugerem que a leptina pode influenciar o eixo reprodutivo por meio de sua ação em neurônios que expressam kisspeptina, no hipotálamo. Uma subpopulação de neurônios kisspeptidérgicos do núcleo arqueado coexpressa a dinorfina e neuroquinina B, que exercem uma ação autorreguladora sobre a secreção de kisspeptina. Considerando que a leptina, a kisspeptina, neuroquinina B e dinorfina são apontados como reguladores do início da puberdade e da função reprodutiva, este trabalho investigou como a dieta hiperlípidica (HFD) pode influenciar esses moduladores ao longo do início do desenvolvimento puberal e após a maturação sexual. Camundongos fêmeas Kiss1-hrGFP foram tratadas com a HFD ou dieta controle a partir do desmame e foram decapitadas aos 28, 32 e 63 dias (Diestro II) e o sangue coletado para dosagem plasmática de leptina, LH e estradiol. Um segundo grupo de fêmeas, tratadas com HFD ou dieta controle, receberam com 32 e 63 dias (Diestro I) uma injeção intraperitoneal de leptina (0,5 mg/kg) ou de veículo, 45 minutos após a injeção foram anestesiadas e submetidas à perfusão cerebral. Cortes hipotalâmicos foram utilizados para realização da técnica de imunoistoquímica para dupla marcação: Kiss1-p-STAT3/ p-STAT3-CART/ Kiss1-Dyn e Kiss1-NKB. Verificamos que a HFD administrada após o desmame, quando comparada à dieta controle, antecipou a abertura vaginal, o primeiro estro e o ínicio da ciclicidade em fêmeas Kiss1-hrGFP. Como indicativo de ativação do eixo reprodutivo neste grupo, foi observado aumento do peso do útero e ovário, aos 32 dias. Esses efeitos estiveram associados com: a) o aumento da concentração plasmática de leptina; b) aumento da ativação de p-STAT3 no núcleo arqueado (ARC) e c) aumento de p-STAT3 em neurônios Kiss1-hrGFP e em neurônios CART do ARC em resposta ao estímulo da leptina. A HFD não afetou a colocalização entre Kiss1-Dyn e Kiss1-NKB em fêmeas no início do desenvolvimento puberal. Em fêmeas Kiss1-hrGFP (63 dias) a administração da HFD por 6 semanas não alterou a regularidade do ciclo estral, houve elevação da leptina plasmática associada com diminuição da expressão da p-STAT3 no ARC em resposta ao estímulo com leptina, sem alterar a responsividade dos neurônios Kiss1-hrGFP a este hormônio. Em conclusão, 9 os resultados demonstram que a antecipação da puberdade induzida pela HFD está associada com o aumento da ação central da leptina, que ao estimular o sistema kisspeptidérgico, direta ou indiretamente, por meio de neurônios CART, pode aumentar o tônus excitatório sobre o eixo reprodutivo. A administração da HFD após o desmame (6 semanas) promoveu uma redução à resposta da leptina no ARC na vida adulta, porém não afetou a responsividade dos neurônios Kiss1-hrGFP a este hormônio e nem a regularidade do ciclo estral nas fêmeas Kiss1-hrGFP. Em conjunto, esses resultados indicam que as ações da leptina nesses neurônios foram preservadas, mesmo com a resistência parcial de suas ações no ARC. Estudos adicionais deverão ser realizados para se avaliar os efeitos a longo prazo da HFD sobre o eixo reprodutivo. / The increase of childhood obesity has been correlated with the early onset of puberty. In prepubertal animals it appears high fat diet (HFD) induces anticipation of puberty. Several studies have indicated that the effect of leptin on reproductive axis can be mediated by its action on Kiss1 neurons in the hypothalamus.A subpopulation of Kiss1 neurons in the arcuate nucleus also shows co-expression of neurokinin B and dynorphin A,presenting a self-regulatory action kisspeptin secretion. Since leptin, kisspeptin, neurokinin B and dynorphin are identified as regulators of puberty onset and reproductive function, this study investigated the influence of high fat diet on these modulators along puberty onset and after sexual maturation. A group of Kiss1-hrGFP-female mice received the HFD or regular chow after weaning. The Kiss1-hrGFP females were decapitated at 28, 32 and 63 days old (Diestrus II) and blood was collected for measurement of plasma leptin, LH and estradiol. A second group of females, treated with HFD or chow after weaning, received at 32 and 63 days old (Diestrus I) an intraperitoneal injection of leptin (0.5 mg / kg) or vehicle, and 45 minutes after they were anesthetized and subjected to cerebral perfusion. Immunohistochemistry was performed for double labeling: Kiss1-p-STAT3/ p-STAT3-CART/ Kiss1-Dyn and Kiss1-NKB in the hypothalamus. It was found that, compared to controls; the HFD anticipated the vaginal opening, the first estrus and the beginning of cyclicity in Kiss1-hrGFP females. An increase in the uterine weight and ovaries, confirmed the activation of reproductive axis in the HFD group at 32 days old. These effects were associated with: a) an increase in plasma leptin concentration; b) the activation of p-STAT3 in the arcuate nucleus (ARC) and c) the increase of p-STAT3 in Kiss1-hrGFP neurons and in CART neurons of the ARC in response to the stimulus of leptin. HFD didnt affect colocalization between Kiss1-Dyn and Kiss1-NKB in females mice at hte pubertal onset . Kiss1-hrGFP female mice (63 days old), exposed to HFD for 6 weeks,exhibited regular estrous cycles, increased plasma levels of leptin associated with a decreased p-STAT3 expression in the ARC after leptin stimulation, with no changes in the responsiveness of Kiss1-hrGFP neurons to this hormone, compared to controls. In conclusion, 11 the results demonstrate that the early puberty induced by the HFD is associated with increased central leptin action, by stimulating the kisspeptidergic system, directly or indirectly, through CART neurons that can increase the excitatory tone in the reproductive axis. The administration of HFD after weaning (6 weeks) induced a decrease on the response to leptin in the ARC in adulthood, but without changes in the responsiveness of Kiss1-hrGFP neurons to this hormone and the regularity of the estrous cycle in Kiss1-hrGFP females. Taken together, these results indicate that the actions of leptin in kisspeptin neurons were preserved after 6 weeks of HFD, despite the partial resistance to this hormone in the ARC. Additional studies should be conducted to evaluate the long-term effects of HFD in the reproductive axis.

Os ratos-de-espinho são abundantes nas florestas úmidas Neotropicais. Trinomys yonenagae (ROCHA, 1995) constitui uma exceção entre as espécies do gênero por habitar o campo de dunas fixas da Caatinga, ser colonial e fossorial. Tanto o ambiente seco, como a socialidade e o hábito fossorial podem alterar o padrão reprodutivo das espécies. Diante do fato desses roedores serem coloniais, por exemplo, espera-se a influência de co-específicos (fêmeas ou machos) no ciclo estral. Estudos-piloto na natureza e em cativeiro mostraram que a fase de diestro pode ocorrer com a vagina aberta, um fato que merece ser mais investigado, já que se considera que a abertura vaginal ocorra somente durante a transição da fase proestro-estro. O objetivo deste trabalho é, portanto, o de estudar aspectos dos ritmos reprodutivos infradianos (ciclo estral e gestação) e circadiano (temperatura corporal) em rabos-de-facho, mantidos em cativeiro, alojados individualmente, e pareados com fêmeas e com machos. Nesses grupos são caracterizados os esfregaços e o estado de abertura da vagina, buscando conhecer aspectos da fisiologia reprodutiva, tais como, a idade de maturidade sexual (cap. 1), a relação entre a fase do ciclo estral e o estado vaginal (cap. 2), e as características da citologia esfoliativa durante a gravidez (cap. 3). Os dados da citologia são correlacionados com o padrão comportamental durante o acasalamento, caracterizando a existência de estro pós-parto (cap. 3). Analisa-se ainda a distribuição de todos os nascimentos ocorridos ao longo de dez anos. O ritmo de temperatura corporal das fêmeas é aferido a partir de acompanhamento da temperatura retal com uso de termômetro digital durante 72h (cap. 4). Embora de maneira geral Trinomys yonenagae siga os padrões reprodutivos de outros membros da família Echimyidae, tais como, gestação longa (90d), ninhadas pequenas (média de 2 filhotes) e maturidade sexual tardia (ao redor dos 90d) é possível identificar a influência de co-específicos (dominância entre fêmeas) no ciclo estral. Este ciclo parece ser espontâneo, do tipo poliéstrico, com fases muito curtas de proestro e estro (< 24h). A condição vaginal não é um bom indicativo de atividade reprodutiva (ocorre abertura no diestro e na gravidez); a presença do macho não garante fecundação; também se confirma a ocorrência de estro pós-parto, igualmente breve. O comportamento de acasalamento é elaborado, o que é esperado de espécies com estro curto ou de vida social e subterrânea. A distribuição dos nascimentos não é sazonal, confirmando dados de campo. Quanto ao ritmo de temperatura corporal, ele é circadiano com picos noturnos e com relação positiva de fase com o ritmo de atividade/repouso, o que segue o padrão geral de roedores / Spiny rats are among the most numerous group of mammals in Neotropical rainforests. Trinomys yonenagae (ROCHA, 1995) is an exception because it is colonial, fossorial and inhabits the semiarid Caatinga. The dry environment and the underground and colonial life styles are known to affect reproductive patterns. So it is expected, for example, that social life may influence the estrous cycle especially through the presence of conspecific (females and males). It is considered that vaginal opening occurs only during the estrus. Previous field studies or in captivity have shown the unexpected occurrence of vaginal opening and diestrus, a fact that deserves further investigation. The aim of this work is verify the reproductive infradian rhythms (estrous cycle and pregnancy) and the circadian body temperature rhythm, in T. yonenagae kept individually or in pairs (male-female and female-female) in captivity. In these groups vaginal smears and the presence of the vaginal membrane is studied aiming to characterize aspects of its reproductive life, such as, the age of sexual maturity (chapter 1), the relationship between the vaginal opening and the phase of the estrous cycle (chapter 2), and the smear cytology during pregnancy (chapter 3). The cytological data are correlated with the mating behavioral, characterizing the post-partum estrus (chapter 3). All birth that occurrence during 10 years are analyzed. The body temperature rhythm is measured during 72h by rectal temperature with a digital thermometer (chapter 4). Although Trinomys yonenagae follows the reproductive patterns of other members of Echimyidae, such as prolonged gestation( 90d), small sized litter (mean of 2) and delayed sexual maturity (around 90d), it is possible to identify the influence of conspecifics (female dominance) upon the estrous cycle. This cycle seems to be spontaneous, poliestric, having very short proestrus and estrus phases (< 24h). The vaginal condition is not a good indicative of the reproductive status (vaginal opening may occur during the diestrus phase and the pregnancy); the presence of males does not guarantee pregnancy. We also confirm the occurrence of post-partum estrus, which is also short-lived. The mating behavior is complex, which is expected in species were the duration of estrus is short, or in species of social and subterranean life. The birth distribution is non seasonal, which is in agreement with field data. The body temperature rhythmicity is circadian with peaks at night; and shows a positive phase relationship with the rest/activity rhythm, both cycles follow the pattern known for other nocturnal rodents

Two distinct stress coping strategies, proactive and reactive, have been stated in various animal studies, each associated with a set of behavioural and physiological characteristics. In a given challenging situation, proactive animals show more aggression, a higher general activity and a predominant sympathetic reaction. In contrast, the reactive copers respond more with immobility and avoidance, and a predominant parasympathetic/hypothalamic activation. This divergence in coping has also been indicated in salmonid fish. Interestingly, many of the differences reported between sea-ranched and wild fish resembles characteristics that differentiate proactive and reactive copers. In the present thesis it is shown that individuals with divergent stress coping styles are identifiable in several brown trout (Salmo trutta) populations. Further, the results show that the distribution of individuals displaying these distinct stress coping strategies differs between populations. This strongly indicates that these traits are heritable and that the variation in selection regime in the native rivers influences these traits. In addition, the results show that populations with hatchery origin are biased towards having higher frequencies of trout displaying a proactive style than populations having wild origin. Also, even though the frequency of early sexual maturation, known as a viable alternative life history in salmonids, differs between populations of brown trout, no link between stress coping strategy and early sexual maturation were found. However, this thesis show that maternal contribution, in the form of egg size, is of major importance whether the progeny will sexually mature early and that it also might be of importance for stress coping strategy. Further, correlations of traits commonly associated with stress coping strategies and behavioural syndromes across context and over time is investigated. The results show that individuals with a strong sympathetic reactivity are more prone to change their behaviour than others.

Pre-harvest sexual maturation in farmed Atlantic salmon, Salmo salar, remains a key biological bottleneck compromising biomass and financial output, production predictability, environmental respect, stock welfare and the overall sustainability of the on-growing industry. The management practices currently in place are not optimized and events of high maturation rate are still sporadically observed. From an ecological perspective, the escape of reproductively competent, domesticated Atlantic salmon constitutes a threat to the integrity of wild stocks. The forecasted expansion of the Scottish salmon industry compels the need for a comprehensive and more reliable control of sexual maturation. The general aim of this research project was to optimize the current management strategy (windows of light-manipulation and quality grading) and test alternative practices (lighting-technologies, selective harvest and triploidization) in the control of pre-harvest sexual maturation within the Atlantic salmon on-growing industry. In that end, a number of trials were performed using stock reared in sea-cages on a full commercial-scale or in tanks on an experimental scale. The results of this project are organized around three experimental chapters dealing consecutively with body-size dimorphism, grading and harvest quality; light manipulations and triploidy. In each chapter, two original manuscripts either published or in review are included. In addition to these experimental results, a literature review chapter composed of two review papers on the photoperiodic synchronization and developmental regulation of maturation in salmonids and on morphological skin colour changes in teleosts (published) are presented. In the first experimental chapters, we aimed at investigating the possibility of detecting and selectively harvesting a high proportion of sexually recruited fish before flesh quality deterioration. Results clearly showed that body-size dimorphisms between maturity cohorts at the end of the anabolic window of reproduction (June/July) are strong and standard predictors of maturation among related populations with the same freshwater history. Dimorphism can therefore be modelled to easily and accurately estimate maturation rate in a number of discrete rearing-units. If required, a high proportion of sexually recruited fish can be selectively harvested as superior quality product while leaving the immature fish for further on-growing. This provides an alternative to visual grilse grading that is not feasible in large-scale aquaculture systems, prevents downgrading and increases production predictability as compared to emergency harvests. Furthermore, our results showed immature males grow faster than immature females which should be further investigated to fully determine gender specific performances and nutritional requirements. Weight-grading performed earlier in the cycle affects the sex-ratio within individual pens and in turn apparent performance. This work also revealed that Atlantic salmon can exhibit significant variations in skin colouration resembling the onset of nuptial display but that are not related to sexual recruitment and do not correlate with reduced flesh quality. This originates from a lack of purine (silver) pigments which was also identified, to a larger extent, as characteristic of the nuptial display. This suggests a degree of desmoltification in these histologically immature fish. The instrumental colouration of the altered phenotype was shown to be improved towards a more silver-like appearance by direct ice-contact. This knowledge could facilitate post-harvest quality grading towards the most appropriate market channel and increase product acceptance and attractiveness. The second experimental chapter investigated the possibility of improving photoperiodic manipulation used to suppress early maturation, currently applied for 6-months during the second winter at sea using wide-spectrum, high-intensity lighting systems. Our results showed that the window of continuous artificial-light (LL) exposure can be reduced to 4-months following its onset in early January without compromising its efficiency in suppressing pre-harvest maturation. In addition, alternative lighting technologies were also highly potent at suppressing sexual maturation. The mean-irradiance (intensity) generated within a commercial sea-cage was inversely proportional to the suppression of nocturnal plasma melatonin (light perception hormone) and negatively correlates with the maturation rate within the commercial sea-pen. Threshold levels of light-intensity required to achieve optimal (total) suppression of sexual maturation are suggested. Alternative, narrow band-width lighting-technologies (cold cathode and light-emitting diodes) present an array of technical, practical, economic and welfare benefits comparing to the system currently in use. Clear improvements of the photoperiod-manipulation strategy were demonstrated and these would reduce economic and environmental costs but also potential impacts on animal welfare. The third experimental chapter showed the strong potential of sterile-triploid Atlantic salmon stocks both in freshwater and seawater. Triploid out-of-season smolts were produced for the first time using a classical accelerated "square-wave" photoperiod. Triploidization affected the smoltification pattern but had no detrimental effects on freshwater and early seawater performances under both a S0+ and S1 regime. This illustrates the need to adapt the timing of seawater transfer for successfully producing triploid Atlantic salmon post-smolts. Following one year of seawater rearing, the prevalence of external deformities was higher in triploids but remained within acceptable levels. Importantly, the incidence of vertebral deformities and ocular cataract was higher in triploids possibly due to their specific requirements. It is suggested that tailoring the diet to the nutritional requirements of triploids holds strong potential for remediation. This must be addressed if the use of sterile-triploid stock is to become a commercial reality. The present research project provides means to optimize the maturation management strategy within the Atlantic salmon on-growing industry through light-manipulation, maturation detection and selective harvest, and quality grading. Proposed improvements have the potential to increase biomass and financial output, production predictability, environmental respect and animal welfare and will allow standardization of the overall control of pre-harvest sexual maturation. Their implementation provides a comprehensive strategy likely to favour a sustainable expansion of the Atlantic salmon industry. From a longer term perspective, the rearing of sterile-triploid stocks is promising and should be actively investigated to isolate domesticated strains from their wild conspecifics. This would also eliminate the need for on-growers to deploy a maturation management strategy that that might still affect stock welfare and remains, despite the strong improvements demonstrated, not 100% reliable, costly, technical and protracted.

Made available in DSpace on 2016-12-06T17:06:49Z (GMT). No. of bitstreams: 1 Knorr, Maria Leticia.pdf: 3664992 bytes, checksum: f1a4c69197ad792d03e5efe732c23dfe (MD5) Previous issue date: 2011-09-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The purpose of the study was to identify the correlation between the variables of the corporal composition and image of corporal composition of children and adolescents during the sexual maturation process. It can be characterized as applied research, quantitative, descriptive and correlational. The sample was composed of 334 subjects (178 male and 156 female) from 8 to 17 years of age, enrolled in Programa Mais Educação , from São José SC, that were selected considering as criteria the enrollment in the program. It was collected corporal mass, height, skin fold and bone diameters data. Corporal fat was calculated using the equations proposed by Slaughter et al. (1988) and the fractioning of corporal mass in four components using equations proposed by Matiegka (1921). To obtain data related to body image, was applied the instrument proposed by Tiggeman and Barret (1998). The difference between body image perceived and desired was calculated using the method proposed by Stunkard (1983) related with body image insatisfaction. To evaluate the stages of sexual maturation, the proposed method was Tanner´s (1962). To describe the sample was used descriptive statistics. To obtain the relationship between the variables was determined the correlation coefficient of Spearman (p). To evaluate the influence of the four components of corporal composition (free fat mass , fat mass, bone mass, residual mass) in the Corporal Mass Index was chosen the determination coefficient (r2). For all the statistical tests was adopted a security level of 95% (p<0,05). It was checked that for males the CMI increases proportionally as the maturation stage goes from G1 to G3, given increase of fat mass and muscular mass in relative terms. Even though it is statistically significant, the correlation between CMI and the sexual maturation stage and between fat mass and sexual maturation stage for male were weak and for female were moderate. The variation between the sexual maturation stages can explain these results and indicate that the evaluation of the CMI regarding the sexual maturation might present limitations. Furthermore, the muscular mass and the sexual maturation stage was moderate. The percentage of fat presented weak and negative correlations for males and moderate for females. All the correlation were stronger for females. For this gender, the fat mass increases progressively while the muscular mass descreases. As the sexual maturation stages evolve, the percentage of fat mass that contributes for the increase of CMI also advances progressively. Considering the three components (muscular mass, residual mass, and bone mass) as free fat mass, it is concluded that the female sample present a gain of fat mass and a loss of free fat mass. The correlation between perceived corporal image and CMI was perceived as moderate for both genders. / O objetivo do estudo foi identificar a existência de congruência entre as variáveis da composição corporal e imagem corporal de crianças e adolescentes durante a maturação sexual. Pode ser caracterizada como pesquisa aplicada, quantitativa, descritiva e correlacional. A amostra foi composta de 334 indivíduos (178 do sexo masculino e 156 do sexo feminino) de 8 a 17 anos, inscritas no Programa Mais Educação de São José-SC que foram selecionados intencionalmente, considerado critério a inscrição do sujeito no Programa Mais Educação. Foram mensurados dados de massa corporal, estatura, dobras cutâneas e diâmetros ósseos. Calculou-se o percentual de gordura corporal pelas equações propostas por Slaugther et al. (1988) e o fracionamento da massa corporal em quatro componentes proposto por Matiegka (1921). Para obtenção de dados referentes à imagem corporal, aplicou-se o instrumento proposto por Tiggeman e Barret (1998). Calculou-se a diferença entre a imagem corporal percebida e desejada proposta por Stunkard (1983) referente a insatisfação com a imagem corporal. Para avaliação dos estágios da maturação sexual foi aplicado a escala proposta por Tanner (1962). Para descrição da amostra, utilizou-se a estatística descritiva. Para obtenção da relação entre as variáveis, foi determinado o coeficiente de correlação de Spearman (p). Para avaliar a influência dos quatro componentes da composição corporal (Massa Magra, Massa Gorda, Massa Óssea, Massa Residual) no Índice de Massa Corporal optou-se pelo coeficiente de determinação (r2). Para todos os testes estatísticos adotou-se um nível de significância de 95% (p<0,05). Verificou-se que no sexo masculino, o IMC aumenta na proporção que o estágio maturacional avança de G1 para G3. Embora estatisticamente significante, a correlação entre o IMC e o estágio de maturação sexual e entre massa gorda e o estágio de maturação sexual para meninos foram fracas e para meninas moderadas. Já entre a massa muscular e o estágio de maturação sexual foi moderado. O percentual de gordura apresentou correlação muito fraca e negativa para meninos e moderada para meninas. Todas as correlações foram mais fortes no sexo feminino. Nas meninas, a massa gorda aumenta progressivamente enquanto que a massa muscular diminui. A medida que os estágios da maturação sexual evoluem, o percentual de massa gorda que contribui frente ao aumento do IMC, avança também progressivamente. Considerando os três componentes (massa muscular, massa residual e massa óssea) como massa magra, conclui-se que as meninas apresentam um ganho de massa gorda e uma diminuição de massa magra. Percebeu-se que correlação entre a imagem corporal percebida e o IMC foi moderada para ambos os sexos.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Nos estuÃrios tropicais, naturalmente complexos devido à dinÃmica de marÃs, perÃodos de precipitaÃÃo pluviomÃtrica atuam como distÃrbio intermediÃrio. As caracterÃsticas ambientais sÃo imprescindÃveis na histÃria de vida da biota da regiÃo, resultando no estabelecimento de padrÃes de reproduÃÃo ou interferindo no metabolismo dos organismos podendo tornÃ-los mais suscetÃveis ao acometimento por parasitas. O bivalve Lucina pectinata (Gmelin, 1791), apesar de apreciado no litoral brasileiro, foi pouco estudado no paÃs atà o momento. Este trabalho teve como objetivo caracterizar a biologia reprodutiva de Lucina pectinata (Mollusca: Bivalvia, Lucinidae) do estuÃrio do rio CearÃ, Fortaleza, CE, Brasil, e efetuar consideraÃÃes sobre parasitismo por trematÃides nesta populaÃÃo, em funÃÃo das variaÃÃes ambientais do local. Os exemplares coletados tiveram as gÃnadas e brÃnquias analisadas histologicamente. Para determinar a maturaÃÃo sexual dos indivÃduos, empregou-se escala gametogÃnica com quatro estÃdios de desenvolvimento gonadal. Lucina pectinata apresentou ciclo reprodutivo contÃnuo, com picos de desova na estaÃÃo seca. O nÃvel de parasitismo na populaÃÃo foi baixo, e a mesma nÃo està sendo prejudicada pela presenÃa de parasitas. Observaram-se semelhanÃa das variÃveis abiÃticas do local durante a mesma estaÃÃo, distinguindo-se nitidamente os perÃodos secos dos chuvosos. O distÃrbio pluviomÃtrico à discutido como fator regulador da populaÃÃo de Lucina pectinata, contribuindo tanto para sua renovaÃÃo quanto para controlar a incidÃncia dos parasitas trematÃides / In tropical estuaries, environments naturally complex due to the tidesÂs dynamics, the rainfall periods act as an intermediate disturbance. The environmental characteristics are important in the biotaâs life history of the region, resulting in the establishment of reproduction patterns or interfering at organisms metabolism making them more susceptible to being affected by parasites. The bivalve Lucina pectinata (Gmelin, 1791), although appreciated in the Brazilian coast, was little studied in the country so far. This study aimed to characterize the reproductive biology of Lucina pectinata (Mollusca: Bivalvia, Lucinidae) from the Cearà river estuary, Fortaleza, CE, Brazil, and make considerations on trematode parasitism in this population, according to local environmental variations. Specimens collected had the gonads and gills assessed histologically. To determine the individuals sexual maturity, was employed gametogenic scale with four stages of gonadal development. Lucina pectinata presented continuous reproductive cycle, with peak spawning at dry season. The level of parasitism in the population was low, and the same is not being affected by the presence of parasites. Were observed proximity of the abiotic variables during the same season, distinguishing clearly the dry periods of rainy. Disturbance rainfall is discussed as a factor regulating the population of Lucina pectinata, contributing to its renewal and to control the incidence of trematode parasites