Le loup ou bar européen effectue une partie de son cycle de vie dans les lagunes et estuaires, des eaux de transitions caractérisées par des fluctuations environnementales plus marquées qu’en milieu marin. Les mécanismes d’acclimatation à la salinité à des températures plus élevées qu’en milieu marin sont encore relativement inexplorés. Dans cette étude, des juvéniles de loup ont été préacclimatés pendant deux semaines à l’eau de mer (EM) à 18 °C (eau tempérée) ou à 24 °C (eau chaude) puis transférés soit dans l’eau douce (ED) soit dans l’EM aux deux températures testées. À 24 °C, les loups parviennent à maintenir leur pression osmotique sanguine relativement constante, quelle que soit la salinité testée. En revanche, la hausse de température affecte significativement différents traits physiologiques liés à l’osmorégulation, la régulation acido- basique, l’excrétion azotée et la production de mucus. Cette étude a notamment montré qu’une acclimatation thermique à 24 °C modifie la structure morphologique de la branchie et induit un déséquilibre de la balance ionique sanguine. Ce déséquilibre concerne particulièrement les ions Na+ et a pour conséquence une diminution du ratio Na+/Cl- plasmatique, pouvant être symptomatique d’une acidose sanguine. Après transfert en douce, une augmentation moins importante de la densité des ionocytes branchiaux et de l’activité de la pompe Na+/K+ ATPase a été observée à 24 °C comparé à 18 °C. De plus, certains transporteurs ioniques jouant un rôle clé dans l’absorption ionique en eau douce n’ont pas été induits au niveau transcriptionnel à 24 °C. Cela suggère une capacité réduite des poissons de passer d’un épithélium branchial hypo-osmorégulateur vers un épithélium hyper-osmorégulateur lors d’un transfert en eau douce à 24 °C vs 18 °C. Au niveau moléculaire, la hausse de température a affecté l’expression de plusieurs transporteurs ioniques branchiaux, notamment en EM. À 24 °C, la surexpression de transporteurs liés au transport de proton H+ pourrait être le signe d’un déséquilibre acido- basique. De plus, l’induction de transporteurs d’ammonium pourrait indiquer un besoin accru d’excréter de l’azote par voie branchiale, potentiellement lié à un métabolisme plus élevé en eau chaude. L’expression des gènes codant pour la protéine chaperonne HSP90 a été fortement affectée par la hausse de température et dans une moindre mesure par la dessalure. Pour finir, l’analyse des mucocytes suggère que la production de mucus pourrait être induite en réponse au stress thermique. Ce type d’étude fonctionnelle sur l’acclimatation à différents régimes de température permet d’apporter des éléments de compréhension pour pouvoir prédire les réponses des téléostéens face aux conséquences du changement global. / The European sea bass Dicentrarchus labrax undertakes seasonal migrations to estuaries and lagoons that are characterized by fluctuations in environmental conditions. It is unclear to what extent salinity acclimation mechanisms are affected at temperatures higher than in the sea, as usually encountered in transitional waters in spring and summer. In this study, juvenile sea bass were pre-acclimated to seawater (SW) at 18 °C (temperate) or 24 °C (warm) for two weeks and then transferred to either fresh water (FW) or SW at the considered temperatures. We have shown that sea bass are able to efficiently maintain blood osmolality at 24 °C at both salinities. However, temperature increase induced significant changes regarding several physiological traits related to osmoregulation, acid-base regulation, ammonia excretion and mucus production. This study showed that thermal acclimation at 24 °C affects gill morphology through gill remodeling and whole-organism ion balance. Plasma Na+ levels seemed to be particularly affected leading to decreased plasma Na+/Cl- ratio in warm conditions, suggesting a blood acidosis. Following FW transfer, the major effects observed were a lower increase in the density of branchial ionocytes and in Na+/K+-ATPase activity at 24 °C compared to 18 °C. Moreover, several key ion transporters involved in ion uptake were not transcriptionally induced following FW transfer at 24 °C. These data suggest a less effective capacity to switch from hypo-to hyper-osmoregulation after FW transfer when fish are exposed to higher temperature. At the molecular level, the temperature increase affected the expression of several branchial transporters, notably in SW. At 24 °C, higher expression of transporters linked to H+ transport might be linked to an acid-base imbalance. Moreover, the induction of ammonia-transporting channels might also indicate increased need for nitrogen excretion, potentially due to enhanced metabolism in warm conditions. Molecular chaperones HSP90 expression was strongly affected by temperature increase and to a lesser extent by salinity decrease. Finally, gill goblet cells analysis suggested that mucus production is increased in response to thermal stress. This study and additional functional studies investigating different temperature regimes provide insights on the effect of increased temperatures on fish responses and may help to predict how teleost will face the consequences of global change.

Foram avaliadas as características hematológicas, mais especificamente a resposta dos elementos de proteção do sangue, de juvenis de pacu, espécie endêmica e neotropical, mantidos em condições adversas e alimentados com dietas contendo colostro bovino liofilizado. Esta primeira secreção láctea, rica fonte de proteínas, moléculas biologicamente ativas e elementos antioxidantes, pode atuar positivamente no sistema de proteção dos animais. No experimento de estresse crônico, juvenis de pacu foram alocados em elevada densidade (50 kg peixe/m3) por 30 dias. No experimento de estresse agudo, os juvenis permaneceram por 15 dias em gaiolas de alimentação, sendo submetidos à baixa concentração de oxigênio (0,75 mg/L). Durante o período experimental, quatro dietas contendo 0, 10, 20 e 30% de colostro bovino liofilizado (CBL) (com 32% de proteína bruta), foram fornecidas duas vezes diariamente (considerando-se quadruplicatas para cada dieta). Antes do início e ao final de cada experimento, analisou-se para cada lote os parâmetros biométricos de biomassa e comprimento para obtenção de análises de desempenho. Oito juvenis para a situação experimental de adensamento, e dez juvenis para a de hipóxia, de cada tratamento, foram anestesiados com benzocaína e amostras de sangue foram coletadas do vaso caudal para análises hematológicas. Foram realizadas análises de eritrograma, leucograma (contagem total e diferencial de leucócitos), hematócrito e calculados os índices hematimétricos. As imunoglobulinas séricas dos juvenis de pacu foram quantificadas através do método de Turvação por Sulfato de Zinco (ZST), que foi padronizado para peixes no presente trabalho. Os juvenis de pacu foram distribuídos em um delineamento experimental inteiramente casualizado no experimento de estresse crônico, e para o de estresse agudo, em blocos, ambos com quatro tratamentos. Os dados foram submetidos à análise de variância, através do procedimento \"General Linear Model\" (PROC GLM) do programa estatístico SAS (1989). Para a avaliação de diferenças entre médias foram efetuados contrastes entre pares de médias utilizando-se o método de Tukey, onde foi considerada a probabilidade de 5% (P<0,05). Não foi observada influência do colostro bovino no desempenho e nas variáveis hematológicas analisadas em ambas situações experimentais, estresse crônico e agudo. Entretanto, para o experimento de estresse agudo, a inclusão de CBL na dieta dos pacus influenciou o número de células granulocíticas especiais, sendo que o grupo que recebeu 0% de CBL apresentou menor número de células que o grupo que recebeu 10% de CBL, assim como o número de monócitos, sendo que o grupo que recebeu 20% de CBL apresentou menor número de células que o grupo que recebeu 30% de CBL na dieta (P<0,05). Embora o colostro bovino não tenha influenciado as variáveis hematológicas analisadas, não houve efeito negativo à esta fonte de proteína heteróloga fornecida aos peixes, uma vez que o desempenho dos animais que receberam o composto na dieta foi semelhante aos animais que receberam dieta sem esta secreção láctea. Considerando os presentes resultados, o colostro bovino liofilizado, uma fonte rica de moléculas bioativas, não contribuiu para a proteção de juvenis de pacu sujeitos à alta densidade de estocagem e baixa oxigenação. / Hematological characteristics were evaluated, specifically the response of blood protection elements of juvenile pacu, endemic and neotropical species, kept under adverse conditions and fed diets containing lyophilized bovine colostrum. This first milk secretion, a rich protein source, biologically active molecules and antioxidant elements, can act positively in the animal protection system. In the chronic stress experiment, juvenile pacu were allocated at high density (50 kg fish/m3) for 30 days. In the acute stress experiment, the juveniles remained for 15 days in feed cages and were submitted to low oxygen concentration (0.75 mg/L). During the experimental period, four diets containing 0, 10, 20 and 30% of lyophilized bovine colostrum (CBL) (with 32% crude protein) were given twice daily (considering quadruplicates for each diet). Before the beginning and the end of each experiment, the biometric parameters of biomass and length were analyzed in each batch for performance analyses. Eight juveniles for the experimental situation of densification and ten juveniles for hypoxia of each treatment were anesthetized with benzocaine and blood samples were collected from the caudal vein for the hematological analysis. Erythrogram, leukogram (total and differential counts of leukocytes), hematocrit and hematimetric indexes were performed. The serum immunoglobulins of the pacu juveniles were quantified by the Zinc Sulfate Turbid (ZST) method, which was standardized for fish in this study. Juveniles pacu were distributed in a completely randomized experimental design for cronic stress experiment, and for acute stress in randomized blocks, both with four treatments. Data were submitted to the \"General Linear Model\"procedure (PROC GLM) of the statistical program SAS (1989). For a mean-to-average assessment, contrasts were performed between pairs of means using the Tukey method, where a probability of 5% (P <0.05) was considered No influence of bovine colostrum was observed on performance and hematological variables analyzed in both experimental situations, chronic and acute stress. However, for the experimental situation of acute stress, the addition of CBL to the diet of pacu influenced the number of special granulocytic cells, and the group that received 0% CBL presented lower number of cells than the group that received 10% CBL, as well as the number of monocytes. The group that received 20% of CBL presented lower number of monocytes than the group that received 30% of CBL in the diet (P <0.05). Although bovine colostrum did not influence the hematological variables analyzed, there was no negative effect on this source of heterologous protein supplied to the fish, since the performance of the animals that received the compound in the diet was similar to the animals that received diet without this milk secretion. Considering theresults, lyophilized bovine colostrum, a rich source of bioactive molecules, does not contribute to the protection of juvenile pacu subjected to high stocking density and low oxygenation.

O objetivo, deste estudo foi investigar o comportamento dos hormônios esteróides 17β-Estradiol (E2), 17α-hidroxiprogesterona (17α-OHP), Testosterona (T) e 11-Ketotestosterona (11-KT), em piracanjuba Brycon orbignyanus de diferentes sexos e idades, na estação reprodutiva, e nas fêmeas submetidas à reprodução induzida. Os animais utilizados no trabalho, eram criados em piscicultura comercial, mantidos em 3 viveiros, separados por lotes de diferentes idades. A coleta dos animais, consistiu de quatro machos e cinco fêmeas (48 meses), identificados através do dimorfismo sexual da espécie, e as demais idades, (12 e 24 meses), coletaram-se, 20 peixes de cada idade, para identificação do sexo através de histologia. Já o experimento de caracterização dos esteróides sexuais na reprodução induzida, foram coletadas cinco fêmeas, selecionadas através das características com: abdome abaulado, papila urogenital, saliente e avermelhada. Após captura, os peixes foram transportados ao laboratório, onde houve coleta de sangue, para quantificação do perfil plasmático de E2, 17α-OHP, T e 11-KT. Posteriormente, os animais foram abatidos e suas gônadas coletadas e fixadas, a fim de que fosse realizada análise histológica para identificação do sexo. Na reprodução induzida, foi coletado sangue em dois momentos: pré-indução (PI) e pós-extrusão (PE). O nível plasmático de E2 nos machos de 12 meses destaca sua ação no processo de proliferação e renovação das espermatogônia observado em machos imaturos. Nas fêmeas o E2 apresentou os maiores níveis (P<0,05) nos animais de 48 meses, confirmando assim, sua principal função na estimulação do processo de vitelogênese, e maturação final do oócito. Quanto aos andrógenos T e 11-KT, os maiores níveis (p<0,05) foram observados nos peixes adultos (48 meses), permitindo afirmar que estes atuam como feedback negativo, do FSH e feedback positivo do LH, fundamental no processo de maturação final e liberação dos gametas, além de regular o comportamento reprodutivo. O resultado da 17α-OHP, sugere que, nas idades estudadas, é indispensável por participar como precursor dos principais esteróides (T, E2 e 11-KT), além da 17α,20β dihydroxy-4-pregnen-3-one (17α,20β-DHP), essencial no estágio final de maturação, e desova na reprodução induzida. / The objective of this study was to investigate the physiological behavior of steroid hormones 17β-Estradiol (E2), 17α-hydroxyprogesterone (17α-OHP), testosterone (T) and 11-Ketotestosterone (11-KT) in Brycon orbignyanus with different sex and ages on the reproductive season and in females submitted to induced reproduction. The animals used in the study were kept in three ponds on a commercial fish farming, separated by lots with different ages. The sampling of animals consisted of the collection of four males and five females (48 months) identified by the sexual dimorphism of the specie. In the other groups (12 and 24 months), 20 fish of each age were collected for identification of sex through histology. In the experiment with characterization of the sexual steroids in the induced reproduction, were collected five females selected through the following characteristics: bulging abdomen and prominent reddish genital papilla. After capture, the fish were transported to the laboratory, where blood was collected for quantification of the plasma profile of E2, 17α-OHP, T and 11-KT Subsequently, the animals were slaughtered and their gonads were collected and fixed for histological analysis. In the induced females, blood was collected at two moments: pre-induction (PI) and post-extrusion (PE). The plasma profile of E2 is fundamental in immature males, highlighting its action in the process of proliferation and renewal of spermatogonia, observed in males of 12 months. In females E2 presented the highest levels (P <0.05) in animals at 48 months, thus confirming its main function in the stimulation of the vitellogenesis process and final oocyte maturation. The highest levels (p <0.05) of T and 11-KT androgens were observed in adult fish (48 months), allowing to affirm that they are acting as FSH negative feedback and LH positive feedback, fundamental in the final maturation and release of the gametes, besides regulating the reproductive behavior of the fish. The results of 17α-OHP suggest this hormon is fundamental in the studied ages because it is a precursor of the main steroids (T, E2 and 11-KT) and 17α, 20β-dihydroxy-4-pregnen-3-one (17α, 20β-DHP), essential in the final stage of maturation and spawning in induced reproduction.

Social interactions can have profound effects on the behavior, physiology, and overall fitness of an individual. An example of this in Lythrypnus dalli is the removal of a male from a social group resulting in a dominant female fish changing sex. The dominant female's transformation involves a suite of changes including brain, behavior, morphology, and physiology. Following the social trigger (male removal), sex-changing individuals' morphology, steroid levels, and changes in the behavior were quantified in the field and compared to results found previously in the laboratory. There were lower rates of aggressive and courtship behavior in the field, but the change in behavior over time had a similar pattern and there were parallels in morphology and steroid levels between lab and field sex changers. The brains of dominant females also responded to social change. Aromatase, an enzyme that converts testosterone into estrogen, and oxytocin, a neuropeptide found in mammals, have been associated with vertebrate social and reproductive behavior. The fish homologue of oxytocin, isotocin, and aromatase are both found in L. dalli. Upon removal of a male from the social group, L. dalli dominant females experienced a decrease in the number of preoptic area isotocin-immunoreactive cells over the course of sex change (7-10 days) and a decrease in brain aromatase activity (bAA) levels within hours, but not minutes, of male removal, while gonadal aromatase activity (gAA) decreased at a much slower time scale (beyond a week). Hours, but not minutes, after male removal, the sex-changing individual's bAA correlated with aggressive behavior increases and not the amount of time following male removal. Males that had just changed from female had different gonadal allocation and higher bAA levels than established males. Subordinate females had high gAA, but their bAA was between that of males and sex changers. In conclusion, dramatic changes in anatomy and neuroendocrine function can occur in response to social cues, individuals with similar reproductive behavior and external morphology can have large neuroendocrine and internal morphologic variation, and social interactions can affect steroid metabolism locally on a short time scale independent of gonadal modulation of steroids.

No description available.

The teleost ovarian follicle undergoes extensive remodeling and regression during the reproductive cycle—a process involving apoptosis and cell death. However, the hormonal regulation of these processes remains unclear. In the current study the role of testosterone in regulating regression of Atlantic croaker (Micropogonias undulatus) ovarian follicles was investigated in co-cultured granulosa/theca (G/T) cells. Testosterone (T) treatment enhanced serum starvation-induced cell death and apoptosis of G/T cells during the mature stage of oocyte maturation. This effect was mimicked by a cell-impermeable T conjugate, T-bovine serum albumin, indicating that this androgen action is initiated at the cell surface. Mibolerone, a nuclear androgen receptor agonist, was ineffective in promoting apoptosis and cell death, which suggests that T actions are independent from the nuclear receptor. Together, the data suggests that T-induction of apoptosis and cell death are through a novel membrane androgen receptor in the croaker ovary. T treatment also increased expression of a pro-apoptotic member of the Bcl-2 gene family, Bax, and two Bax upstream regulators, JNK and p53. These results suggest that T induces cell death of G/T cells in croaker through the apoptotic pathway involving JNK, p53 and Bax. An opposite response of cell death protection by T was also observed in G/T cells cultured from late-stage ovaries. This response was accompanied by a rapid increased ERK-1/-2 phosphorylation not seen in Mibolerone treatment. By examining the role of T in croaker follicle cell death and elucidating the corresponding basic mechanisms of androgen action, we are learning more about the regulatory components involved in the breakdown and remodeling stages of the teleost reproductive cycle. / text

The African bonytongue (Heterotis niloticus), one of two living species of the primitive teleost family Arapaimidae, constitutes an important artisanal and commercial fishery in West Africa. This species has also been proposed for wide aquaculture use in Africa. Despite its importance, information on the levels of genetic differentiation for this fish in Benin is lacking, which can contribute to its conservation and management. In this study, regional and local scale genetic differentiation of the African bonytongue in Benin, West Africa, was examined using six microsatellite markers. In total, 221 H. niloticus individuals were sampled from 12 localities in Benin that include three river basins: Oueme-So (ten localities sampled); Mono (one locality); and Niger (one locality). The results showed a high degree of genetic differentiation between African bonytongue samples from the three river basins, which was expected given the barriers for dispersal for aquatic organisms. For the Oueme-So floodplain, they indicate high and homogeneous gene flow, suggesting that seasonal flooding facilitates gene flow across this region. The information obtained from this study will be useful for defining management units for H. niloticus in Benin, and caution against the translocation of individuals from different basins.

At present, there is a general lack of information regarding the spatial genetic architecture and genetic diversity of estuarine and coastal freshwater fish in Australia or about the interacting intrinsic, extrinsic and historical influences responsible for sculpting these patterns. This thesis represented the first investigation of the phylogeographic structure and recent evolutionary histories of teleost fishes from the coastal and estuarine environments of south-western Australia, using the resolution afforded by mtDNA sequence data. Available evidence indicated that, to different degrees, these species have limited potential for dispersal amongst local assemblages from different water bodies. As this theoretically reduces the confounding effects of recent gene flow on extant genetic structure, these fishes were well suited to studying the influences of historical factors. Historical influences were expected to be particularly profound, given that these coastal environments underwent massive modifications during Late Quaternary eustatic fluctuations. The thesis consists of four major components, which explored different aspects of interspecific and intraspecific phylogeny and p hylogeograp hy of three teleost species, based on mtDNA control region and cytochrome b fragments. First, the relationship between the endemic, 'strictly estuarine' Leptatherina wallacei (Atherinidae) and the more widespread, 'estuarine & marine' 6. presbyteroides was examined, with a view to establishing whether 6. wallacei represents a monophyletic or polyphyletic lineage and whether this species was derived recently (i.e. in Holocene estuaries). Second, the phylogeographic structure and genetic diversity of L. wallacei were investigated and compared with data from L. presbyteroides, with a view to using this information to interpret the recent evolutionary histories of each congener. Third, the divergence between assemblages of L. wallacei inhabiting two isolated coastal lakes was used to estimate a maximal substitution rate for the control region, which was then used to infer general time frames for the divergence between the two Leptatherina species and between the major phylogeographic partitions within each species. Fourth, investigations were initiated into phylogeographic patterns and levels of genetic diversity within and among assemblages of Pseudogobius olorum (Gobiidae) from several coastal lakes and an estuary. Phylogenetic analyses indicated that the two Leptatherina species were characterised by exclusive and reciprocally-monophyletic lineages of haplotypes from both mtDNA regions, supporting the monophyletic origins of L. wallacei. Both 6. wallacei and 6. presbyteroides exhibited high levels of genetic diversity and extensive overall subdivision (e.g. Qsr = 0.691 & 0.644 respectively for control region data). There was a profound phylogeographic break in both species between all conspecific assemblages from the lower west coast (LWC phylogroup) and all those from the south coast (SC phylogroup), which suggested the influences of shared extrinsic and/or historical factors. There was limited genetic structuring within the two major phylogroups of either Leptatherina species, apparently reflecting recent connectivity amongst local assemblages, with subsequent fragmentation and insufficient time for lineage sorting. However, two major phylogeographic breaks distinguished monophyletic control region phylogroups of L. wallacei from the isolated coastal Lake Clifton and Lake Walyungup, consistent with their independent evolution following lacustrine entrapment during the Holocene. The divergence between these two isolated lacustrine assemblages of Leptatherina wallaceiformed the basis for an estimate of the maximal substitution rate of the control region. While these data were unable to provide a precise estimate of the actual rate of molecular evolution, all the evidence suggested that it was proceeding very rapidly. The maximal rate estimate of 172.3% lineage-' MY-' was among the fastest ever reported. Based on this rate, the two Leptatherina species diverged at least 1 SKya, thus rejecting a Holocene origin for L. wallacei. The divergence between the LWC and SC phylogroups of L. wallacei has been ongoing for at least GKya, while the equivalent divergence in L. presbyteroides has been ongoing for at least 11 Kya. As the time frames of these divergences were consistent with periods of massive environmental modifications associated with the end-Pleistocene fall in sea level and the HMT, it was likely that these factors have played important roles in sculpting the species' divergence and intra-specific genetic structure. Although useful in temporally scaling genetic divergences within and between the two Leptatherina species, wider application of this rate estimate to questions regarding other taxa was limited. For example, evident rate heterogeneity between the genera precluded its use with even the relatively closely-related atherinid Atherinosoma elongafa. Phylogeographic analyses identified high levels of genetic diversity and extensive genetic subdivision (e.g. st = 0.652 for control region) amongst an estuarine and several lacustrine assemblages of Pseudogobius olorum, although phylogeographic structure was shallower than in either Leptatherina species. There was increased divergence between three assemblages from the lower west coast and two from the south coast, consistent with the profound break evident in the Leptatherina. One lacustrine assemblage appeared to represent a distinct lineage and a preliminary maximal rate estimate (~61.4% lineage-1 MY-1) was calculated based on the minimum divergence of this assemblage from its nearest conspecifics. Although slower than the rate calculated for L. wallacei, this was still high for teleost fishes. Overall, this study indicated that historical environmental factors, especially those related to Quaternary eustatic changes, have played important roles in sculpting the phylogeography and evolution of three teleost species from south-western Australia. Moreover, as these species have differential dependencies on estuarine environments (is. 'strictly estuarine' vs 'estuarine & marine') and represented two different taxonomic groups (i.e. Atherinoidei & Gobioidei), historical environmental factors may have exerted similar influences on other coastal species in the region.

Submitted by Roberta Martins Crivelaro null (robertamc.vetunesp@hotmail.com) on 2018-04-04T13:28:30Z No. of bitstreams: 1 Crivelaro_RM_Tese_Doutorado.pdf: 54255477 bytes, checksum: 59fad4a92042108771349ee8c36dca9c (MD5) / Rejected by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br), reason: Solicitamos que realize correções na submissão seguindo as orientações abaixo: No arquivo pdf submetido ao repositório não consta a ficha catalográfica e o certificado de aprovação (documentos obrigatórios). Peço que insira os mesmos no arquivo pdf e depois faça uma nova submissão. Agradecemos a compreensão on 2018-04-04T14:03:35Z (GMT) / Submitted by Roberta Martins Crivelaro null (robertamc.vetunesp@hotmail.com) on 2018-04-04T15:29:19Z No. of bitstreams: 1 Crivelaro_RM_Tese.pdf: 54429572 bytes, checksum: 4d5ef09be8bb95df6635d4fb516cef61 (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2018-04-04T18:00:56Z (GMT) No. of bitstreams: 1 crivelaro_rm_dr_jabo.pdf: 54429572 bytes, checksum: 4d5ef09be8bb95df6635d4fb516cef61 (MD5) / Made available in DSpace on 2018-04-04T18:00:56Z (GMT). No. of bitstreams: 1 crivelaro_rm_dr_jabo.pdf: 54429572 bytes, checksum: 4d5ef09be8bb95df6635d4fb516cef61 (MD5) Previous issue date: 2018-02-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As doenças cardiovasculares constituem grande problema de saúde pública. A necessidade do entendimento do processo de remodelação cardíaca tem acarretado em aumento do número de pesquisas envolvendo terapias biológicas. Neste contexto, peixes teleósteos emergem como opção de modelo experimental, pois possuem homologia morfofuncional e imunológica com mamíferos. Tilápias-do-Nilo (Oreochromis niloticus) já vêm sendo empregadas no estudo de diversas doenças que afetam seres humanos. Com a presente pesquisa, objetivou-se desenvolver técnica de acesso videocirúrgico e induzir lesão cardíaca mecânica, em tilápias-do-Nilo; avaliar a eficácia da metadona no controle da dor associada à lesão; e caracterizar os mecanismos de remodelação do miocárdio ventricular, empregando-se avaliações por eletrocardiograma e por microscopias. As avaliações foram conduzidas antes, 1 h depois, e transcorridos 7, 14, 30, 60 e 90 dias da lesão cardíaca. O acesso à cavidade celomática foi realizado utilizando-se um punch de biopsia de 3 mm, permitindo a introdução de endoscópio para posterior amputação do ápice do coração. O procedimento foi executado rapidamente e com baixo índice de mortalidade transoperatória (5,60%) e pós-operatória (3,38%). Aproximadamente 6% de tecido cardíaco, apresentando epicárdio e miocárdio, foi removido com a pinça de biopsia, sendo que a videocirurgia permitiu boa visibilização interna, padronização do tamanho da lesão e alta precisão. A avaliação da analgesia fornecida pela metadona foi realizada por meio de parâmetros fisiológicos e comportamentais. Os resultados demonstraram que, na dose empregada, a metadona não possuiu efeito analgésico em tilápias-do-Nilo, contudo, o tempo de recuperação da anestesia foi maior entre os animais que receberam metadona, sugerindo um possível efeito sedativo do fármaco. Os ventrículos da tilápia-do-Nilo, após lesão, não apresentaram evidências de regeneração e evoluíram para um processo de remodelamento caracterizado pelos espessamentos das paredes do ventrículo e do epicárdio, pela hipertrofia dos cardiomióticos, e por alterações em atividade elétrica. Mudanças no estado ordenado de agregação do colágeno intersticial, no tamanho e no formato dos núcleos dos cardiomiócitos, e na supraorganização da cromatina nuclear dos cardiomiócitos, bem como presença de células poliplóides, de células necróticas e de células apoptóticas foram observadas. Em conclusão, a tilápia-do-Nilo parece ser um bom organismo modelo para estudos em cardiologia experimental, uma vez que seu ventrículo, após amputação do ápice do coração, acumula muitas das alterações vistas em corações de pacientes humanos cardiopatas. Vantagens adicionais referentes ao emprego de tilápias-do-Nilo em pesquisas incluem o tamanho dos animais, o que possibilita a utilização de técnicas menos onerosas; e a facilidade de alojamento e de manutenção de um grande número de indivíduos num espaço reduzido, com baixa taxa de mortalidade. / Cardiovascular disease are a public health big problem. The need for understanding cardiac repair mechanism has increased the number of researches biologic therapy field. In this context, teleost fish show as a experimental model, as they have morpho-functional and immunologic homology whit mammals. Nile tilapia (Oreochromis niloticus) has been used to study several diseases that affect humans. The present study aimed to develop a video surgery access and mechanically induce cardiac injury in Nile tilapia; to evaluate the analgesic activity of methadone in effectively control the pain associated with the injury; and characterize myocardial repair mechanisms by microscopy and electrocardiogram analysis. Data were recorded before cardiac injury and then 1 hour, 7, 14, 30, 60 and 90 days after cardiac injury. The access to coelomatic cavity was made with a 3-mm biopsy punch, allowing the passage of an endoscope for amputation of the cardiac apex. The procedure was quickly performed with intraoperative (5.6%) and post-operatory (3.38%) low mortality rates. Approximately 6% cardiac tissue, including epicardium and myocardium were removed with the biopsy forceps, once video surgery allowed good visualization, standard lesion areas and great precision. To evaluate the analgesic effect of methadone, physiological and behavioral parameters were recorded. Results show that in the dose used, methadone did not show analgesic effect in Nile tilapia. However, recovery time was longer in fish that received methadone, suggesting a sedative effect of the drug in the specie. The ventricles of Nile tilapia, after lesion, did not showed any evidence of regeneration, progressing for a remodeling process, characterized by a thicker ventricle wall and epicardium, by cardiomiocytes hypertrophy, and changes in electrical activity. Changes in the interstitial collagen aggregation state, size and shape of cardiomiocytes nuclei, and in the supra-organization of nuclear chromatin of cardiomiocytes, as well as presence of ploydy, necrotic and apoptotic cells, were also oberved It was concluded that Nile tilapia seems to be a good experimental model organism for experimental cardiology studies, once its ventricle, after have its apex amputated, shows many of the alterations observed in hearts of humans cardiac patients. Additional advantages regarding the use of Nile tilapia in research include the size of the animals, that allows the use of cheaper techniques; and the practical way to keep a great number of animals in small spaces, with low mortality rates.

Pharmaceuticals, enter the aquatic environments through sewage treatment plants and may affect fish. This examination paper is a literature study that focuses on Selective serotonin reuptake inhibitors, SSRIs, exposure and the impacts on teleosts in the Baltic Sea by assessment of peer-reviewed literature and material. Teleosts affected by exposure of these substances may demonstrate physiologically as well as behavioral alterations. These can be observed as alterations in aggression, boldness, mobility, growth, feeding rate or in endocrine processes. The potential of which SSRI may effect teleosts depends on the pH of the aquatic environment, temperature, other contaminants and the fat solubility of the substances. Some effects caused by SSRI exposure may elicit ecological impacts. These particularly concern changes and effects in terms of evasiveness, reproductive capacity and ability to find food as well as alterations of interspecificity. Even the balance between population density, individual fitness and by extension survival might be affected. Effects in interspecificity may potentially lead to local extinctions and changes in food webs. Furthermore, results demonstrated that when a substance is bioaccumulated and the teleosts are eaten by predators on higher trophic levels, marine ecosystems can also be affected. Moreover a conclusion could be drawn the level of concentration of SSRIs in the aquatic environment may be of less significance since teleosts have the potential to bioaccumulate SSRIs in tissue over time and in this sense concentrations may reach harmful levels that can cause physiological or behavioural alterations. Continuous studies should refer to chronic tests studies with focus on a field testing environment for understanding of natural conditions and exposure. Furthermore, studies on how ecosystems may be affected should be important to give an overview of the problem with SSRI exposure. As the Baltic Sea is a sensitive environment, studies should preferable be made on species living in this environment.