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In mammals, the development of male or female gonads from fetal bipotential gonads depends on intricate genetic networks. Changes in dosage or temporal expression of sex-determining genes can lead to differences of gonadal development. Two rare conditions are associated with disruptions in ovarian determination, including 46,XX testicular differences in sex development (DSD), in which the 46,XX gonads differentiate into testes, and 46,XX ovotesticular DSD, characterized by the coexistence of ovarian and testicular tissue in the same individual. Several mechanisms have been identified that may contribute to the development of testicular tissue in XX gonads. This includes translocation of SRY to the X chromosome or an autosome. In the absence of SRY, other genes associated with testis development may be overexpressed or there may be a reduction in the activity of pro-ovarian/antitesticular factors. However, it is important to note that a significant number of patients with these DSD conditions have not yet recognized a genetic diagnosis. This finding suggests that there are additional genetic pathways or epigenetic mechanisms that have yet to be identified. The text will provide an overview of the current understanding of the genetic factors contributing to 46,XX DSD, specifically focusing on testicular and ovotesticular DSD conditions. It will summarize the existing knowledge regarding the genetic causes of these differences. Furthermore, it will explore the potential involvement of other factors, such as epigenetic mechanisms, in developing these conditions.

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A particularly concerning outcome of environmental pollution is the disturbance of reproductive processes. However, studies on the impacts of pollution on the reproductive health of fish inhabiting South American environments are limited. We studied the impact of anthropogenic pollution on the reproductive health of two sympatric Patagonian marine fish species with different reproductive strategies: the live-bearing rockfish Sebastes oculatus and the egg-laying Brazilian sandperch Pinguipes brasilianus. Our findings reveal that both species presented some degree of reproductive disturbance when inhabiting an affected site, but the specific alterations differed depending on the species, sex, and season. During the reproductive season, 17ß-estradiol levels were elevated in females of both species living in polluted areas, while no differences in androgen levels were observed in either species or season. The gonadosomatic index (GSI) was affected in both sexes of S. oculatus during the non-reproductive season, while the gonadal stages were mainly affected in both sexes of P. brasilianus. No signs of intersex condition were observed. Our results highlight the importance of including diverse reproductive parameters to better understand anthropogenic effects on wild animals. Long-term studies including other fish species and including offspring (to evaluate possible transgenerational effects) will be necessary to determine the consequences of the documented reproductive alterations, particularly whether fish species inhabiting Patagonian marine reef areas will be able to reproductively adapt to increasing marine anthropogenic disturbances.

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This study aimed to describe and characterize the stages of gonadal development of females of Xiphopenaeus kroyeri caught by artisanal fishers in Espírito Santo state, southeastern region of Brazil. All females (n= 1,831) were subjected to macroscopic and microscopic morphological analysis (n= 333) of the ovaries. From the morphology, coloration and degree of turgidity of the fresh ovary, macroscopic analysis determined five stages of gonadal development. The macroscopic analysis showed difficulties in differentiating the immature and spawning stages due to the similarity between the colors of the ovaries, which confirms the need to perform the macroscopic and histological analysis simultaneously for fisheries management studies. Microscopic observations allowed us to analyze the following six stages of cell development: oogonia, previtellogenic oocytes, primary vitellogenic oocytes, secondary vitellogenic oocytes, mature oocytes and atretic oocytes. From this, five stages of gonadal development were defined, i.e., immature, early development, advanced development, mature and spawned. The presence of peripheral bodies was not observed in this species. These results help to clarify and better understand the reproductive and population aspects of the Atlantic Seabob, which are fundamental for the establishment of management and conservation measures of this resource.

Este estudo teve como objetivo descrever e caracterizar os estágios de desenvolvimento gonadal de fêmeas de Xiphopenaeus kroyeri capturado por pescadores artesanais no Estado do Espírito Santo, região sudeste (Região sudeste = Rio de Janeiro, São Paulo, Minas Gerais e Espírito Santo) do Brasil. Todas as fêmeas (n= 1.831) foram submetidas à análise morfológica macroscópica e microscópica (n= 333) dos ovários. A partir da morfologia, coloração e grau de turgidez do ovário fresco, a análise macroscópica determinou cinco estágios de desenvolvimento gonadal. A análise macroscópica mostrou dificuldades em diferenciar os estágios imaturo e reprodutivo devido à semelhança entre as cores dos ovários, o que confirma a necessidade de realizar a análise macroscópica e histológica simultaneamente para estudos de manejo pesqueiro. As observações microscópicas permitiram analisar os seguintes seis estágios de desenvolvimento celular: oogônias, ovócitos prévitelogênicos, ovócitos em vitelogênese primária, ovócitos em vitelogênese secundária, ovócitos maduros e ovócitos atrésicos. A partir disso, foram definidos cinco estágios de desenvolvimento gonadal, ou seja, imaturo, desenvolvimento inicial, desenvolvimento avançado, maduro e desovado. A presença de corpos periféricos não foi observada nesta espécie. Estes resultados ajudam a esclarecer e compreender melhor os aspetos reprodutivos e populacionais do camarão do Atlântico, que são fundamentais para o estabelecimento de medidas de gestão e conservação deste recurso.

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La reproducción sexual es la forma de propagación más antigua y universal utilizada por los vertebrados. Los mecanismos que controlan la determinación sexual y la diferenciación en estos animales son diversos y dependen de una amplia variedad de factores genéticos, así como en algunos casos de factores ambientales. El sexo genético puede definirse por factores genéticos hereditarios que se determinan en la fertilización. Por otro lado, la diferenciación gonadal depende de la activación de factores transcripcionales que se expresan durante la ventana de diferenciación sexual. Dichos factores pueden tener su expresión alterada por condiciones ambientales como la temperatura y la osmolaridad, entre otros. Estos procesos sexuales se dividen clásicamente en determinación y diferenciación sexual, respectivamente. Con base en tales hechos, esta revisión tiene como objetivo mostrar los fundamentos básicos de los procesos de determinación y diferenciación sexual en vertebrados, enfatizando el grupo de peces teleósteos.(AU)

Sexual reproduction is the oldest and universal form of propagation used by vertebrates. The mechanisms that control sexual determination and differentiation in these animals are diverse and depend on a wide variety of genetic factors as well as in some cases environmental factors. Genetic sex can be define by hereditary genetic factors that are determined in fertilization. On the other hand, gonadal differentiation depends on the activation of transcriptional factors that are expressed during the sexual differentiation window. Such factors may have their expression altered by environmental conditions such as temperature and osmolarity, among others. These sexual processes are classically divided into sexual determination and differentiation, respectively. Based on such facts, this review aims to show the basic theoretical reasoning of the processes of sexual determination and differentiation in vertebrates, emphasizing the group of teleost fishes.(AU)

A reprodução sexual é a forma de propagação mais antiga e universal utilizada pelos vertebrados. Os mecanismos que controlam a determinação e diferenciação sexual nestes animais são diversos e dependem de uma grande variedade de fatores genéticos bem como em alguns casos de fatores ambientais. O sexo genético pode ser definido por fatores genéticos hereditários que são determinados na fecundação. Por outro lado, a diferenciação gonadal depende da ativação de fatores transcricionais que são expressos durante a janela de diferenciação sexual. Tais fatores podem ter sua expressão alterada por condições ambientais como a temperatura e a osmolaridade dentre outros. Estes processos sexuais são classicamente divididos em determinação e diferenciação sexual, respectivamente. Baseados em tai fatos, esta revisão tem como objetivo mostrar a fundamentação básica dos processos de determinação e diferenciação sexual em vertebrados com ênfase no grupo dos peixes teleósteos.(AU)

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La reproducción sexual es la forma de propagación más antigua y universal utilizada por los vertebrados. Los mecanismos que controlan la determinación sexual y la diferenciación en estos animales son diversos y dependen de una amplia variedad de factores genéticos, así como en algunos casos de factores ambientales. El sexo genético puede definirse por factores genéticos hereditarios que se determinan en la fertilización. Por otro lado, la diferenciación gonadal depende de la activación de factores transcripcionales que se expresan durante la ventana de diferenciación sexual. Dichos factores pueden tener su expresión alterada por condiciones ambientales como la temperatura y la osmolaridad, entre otros. Estos procesos sexuales se dividen clásicamente en determinación y diferenciación sexual, respectivamente. Con base en tales hechos, esta revisión tiene como objetivo mostrar los fundamentos básicos de los procesos de determinación y diferenciación sexual en vertebrados, enfatizando el grupo de peces teleósteos.

Sexual reproduction is the oldest and universal form of propagation used by vertebrates. The mechanisms that control sexual determination and differentiation in these animals are diverse and depend on a wide variety of genetic factors as well as in some cases environmental factors. Genetic sex can be define by hereditary genetic factors that are determined in fertilization. On the other hand, gonadal differentiation depends on the activation of transcriptional factors that are expressed during the sexual differentiation window. Such factors may have their expression altered by environmental conditions such as temperature and osmolarity, among others. These sexual processes are classically divided into sexual determination and differentiation, respectively. Based on such facts, this review aims to show the basic theoretical reasoning of the processes of sexual determination and differentiation in vertebrates, emphasizing the group of teleost fishes.

A reprodução sexual é a forma de propagação mais antiga e universal utilizada pelos vertebrados. Os mecanismos que controlam a determinação e diferenciação sexual nestes animais são diversos e dependem de uma grande variedade de fatores genéticos bem como em alguns casos de fatores ambientais. O sexo genético pode ser definido por fatores genéticos hereditários que são determinados na fecundação. Por outro lado, a diferenciação gonadal depende da ativação de fatores transcricionais que são expressos durante a janela de diferenciação sexual. Tais fatores podem ter sua expressão alterada por condições ambientais como a temperatura e a osmolaridade dentre outros. Estes processos sexuais são classicamente divididos em determinação e diferenciação sexual, respectivamente. Baseados em tai fatos, esta revisão tem como objetivo mostrar a fundamentação básica dos processos de determinação e diferenciação sexual em vertebrados com ênfase no grupo dos peixes teleósteos.

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The reproductive strategy of the non-native predator cichlid Cichla kelberi was determined to explain its success after more than 60 years of being introduced into an isolated reservoir in southeastern Brazil. This was one of the first-known translocations of the genus Cichla out of its natural range. Macro- and microscopy characteristics of the gonadal development stages and the maturation phases, along with the reproductive features (size at first maturation size, gonado-somatic index and sex ratio), were described. It was hypothesized that the stable conditions of the reservoir, with low connectivity, weakly defined spatial gradient and slight seasonal changes in environmental variables, favour the equilibrium strategy that enables predators to have high offspring survivorship because of great parental investment in individual progeny. Sex ratio was well balanced, with males and females reaching first maturity between 30.0 and 28.6 cm total length (LT ), respectively. The stages of oocyte (primary and secondary growth, vitellogenic and atresia) and spermatocyte (spermatogonia, spermatocytes, spermatids and spermatozoa) development were identified. Five phases of gonadal development (immature, developing, spawning capable, regressing and regenerating) were described for both sexes. A long reproductive season was found, with spawning peaks in August/September and, to a lesser extent, in April/May. Parental care and spawns in parcels (batch spawns) corroborated the raised equilibrium strategy that was effective in this isolated reservoir. This species developed reproductive mechanisms that fit to different environmental conditions, with multiple spawning being associated with lentic environments and asynchronous development of oocytes, which are released over long periods. The reproductive plasticity in reservoirs may be one of the main factors inherent to the successful of colonization and establishment of the peacock bass in the environments in which they were introduced.

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SUMMARY: Establishing guidelines for responsible management in fish production systems requires knowledge of the basic biology of the fish to be raised. The objective of this work was to determine the reproductive capacity of hybrids produced from the crossing of females of Pseudoplatystoma metaense with males of Leiarius marmoratus. Males presented a digitiform, unrestricted spermatogonial testicle containing caudal digits producing glycoproteins that do not form a seminal vesicle. It was possible to find free sperm in the lumen of the tubules and in the ducts. The ovary of the females was found to be saccular and synchronous with at least three groups of oocytes. In the first year of life, only oogonia up to previtellogenic oocytes (cortical alveolus 284.9 ± 35.7 mm in diameter) were found. After the second year vitellogenic oocytes 730 ± 3.78 mm in diameter were observed. The events of gonadal development of the hybrids indicate that they are gonochoric, synchronic animals. The maturation peaks in the high-water season, overlapping with the parental species. Therefore, the escape of hybrids from fish cultures to the rivers may increase the risk of crosses, gene introgression, or diminution of the reproductive capacity of the pure species.

RESUMEN: El establecimiento de pautas para la gestión responsable en los sistemas de producción de peces requiere el conocimiento de la biología básica de los peces a criar. El objetivo de este trabajo fue determinar la capacidad reproductiva de los híbridos producidos por el cruce de hembras de Pseudoplatystoma metaense con machos de Leiarius marmoratus. Los machos presentaron un testículo espermatogonial digital no restringido que contiene dígitos caudales que producen glucoproteínas que no forman una vesícula seminal. Fue posible encontrar esperma libre en la luz de los túbulos y en los conductos. Se encontró que el ovario de las hembras era sacular y sincrónico con al menos tres grupos de ovocitos. En el primer año de vida, solo se encontraron oogonia hasta ovocitos previtelogénicos (alvéolo cortical de 284,9 ± 35,7 mm de diámetro). Después del segundo año, se observaron ovocitos vitelogénicos de 730 ± 3,78 mm de diámetro. Los eventos de desarrollo gonadal de los híbridos indican que son animales sincrónicos gonocóricos. La maduración alcanza su punto máximo en la temporada de aguas altas, superponiéndose con las especies parentales. Por lo tanto, el escape de híbridos de cultivos de peces a los ríos puede aumentar el riesgo de cruces, introgresión genética o disminución de la capacidad reproductiva de las especies puras.

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Introduction: Puberty normally begins after 8 years in girls and 9 years in boys. Objective: To determine the prevalence of signs of precocious puberty (PP), breast development in girls, premature gonadal development (PGD), premature adrenarche (PA), menarche age (MA) and its association with nutritional status (NS). Material and Methods: From a sample of 3.010 children from 5 to 14 years randomly selected in Santiago of Chile were chosen a subsample of 873 kids according to the cutoff to define PP. Survey was applied to obtain MA. Logistic regression were used to evaluate the relationship between PP and NS. Results: In boys the prevalence of PGD and PP was 8.55% and 3.16% respectively, no relationship was found with nutritional status In girls the prevalence of breast development and PA was 8.13% and 0.9% respectively. Only there be association between PP and NS in women: with a prevalence of 1,2%, 13,9% and 21,1% in well-nourished, Overweight and obesity are at greater risk of showing PP compared with eutrophic girls with an OR of 25,5 (IC 95% 3,2-203,0) and 46.93 (IC 95% 6,1-361,5). MA was 12,01 ± 0,94 years in eutrophic girls and 11,40 ± 0,96years in obese girls (p< 0,05). Conclusion: There was a positive correlation in females between overweight and obesity an PP and MA. There is a secular trend in MA, to compare these findings with other national studies. Obesity could have an important role in explaining the advancement observed in pubertal development.

Introducción: El desarrollo puberal se inicia normalmente después de los 8 años en niñas y de los 9 años en varones. Objetivo: Estimar la prevalencia de signos de pubertad precoz (sPP): crecimiento genital (CG) en varones, telarquia en niñas y vello púbico (VP) en ambos sexos; y determinar edad de la menarquia (EM) en una muestra de escolares de Santiago de Chile), y evaluar la asociación de estas variables con el estado nutricional (EN). Material y Métodos: Se examinaron 3.010 escolares de clase media baja de 6 a 14 años, pertenecientes a 10 colegios de Santiago de Chile y seleccionados aleatoriamente. En todos ellos se consignó peso, talla, IMC y desarrollo puberal según Tanner. Se aplicó una encuesta a los padres para obtener la EM a la población total de mujeres (n= 1.433). Para determinar sPP se analizaron por separado los 867 niños (62% mujeres) menores a la edad establecida como puntos de corte para definir PP. Se utilizó regresión logística para determinar la asociación existente entre sPP y el EN. Resultados: En varones la prevalencia de CG y VP fue de 8,55% y 3,16% y no se asocio al EN. La prevalencia de telarquia y VP en niñas fue de 8,13% y 0,9% respectivamente. Se observó una fuerte asociación entre telarquia y EN con prevalencias de 1.2%, 13.9% y 21.1% en eutróficas, sobrepeso y obesas, respectivamente (p< 0,0001) (Gráfico 1). La presencia de sobrepeso y/o obesidad otorgan un mayor riesgo de presentar telarquia, vs comparación con las niñas eutróficas con un OR de 25,5 (IC 95% 3,2-203,0) y 46.93 (IC 95% 6,1-361,5), respectivamente. La EM fue 12,01 ± 0,94 años en niñas eutróficas siendo de 11,40 ± 0,96 años en niñas obesas (p< 0,05). Conclusión: Se observó una correlación positiva solo en el sexo femenino entre malnutrición por exceso, telarquia precoz y EM. Se observa una tendencia secular en la EM al comparar los hallazgos con otros estudios nacionales.

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This study evaluated the reproductive characteristics of pike-characids, Boulengerella cuvieri, during the hydrological cycle in the Xingu River, eastern Amazon. The sex ratio was 1:1 and the gonado-somatic index and relative frequency of maturation stages indicate a short breeding season of single phase spawning that coincides with a filling and flood period. Mean standard length at first sexual maturity for female B. cuvieri was estimated to be 22·9 cm.

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Estudou-se o tecido germinativo ovariano do peixe Melanotaenia boesemani. Por meio de análises morfológicas das gônadas, realizadas após a confecção de lâminas histológicas elaboradas em parafina e coradas com hematoxilina-eosina, foram descritos os tipos celulares encontrados e realizada a classificação do estádio de maturidade dos peixes. Macroscopicamente, foi identificado que a referida espécie possui ovário único, arredondado e, na fase observada, amarelado, localizado na parte látero-anterior da cavidade celomática. As fêmeas analisadas foram classificadas na escala de desenvolvimento gonadal como maduro/em reprodução. A presença de folículos vazios e marcas de desova nas lamelas ovulígeras mostrou-se evidente. Nos ovócitos vitelogênicos deste peixe, foi constatada a presença de filamentos de adesão ovocitária ancorados à zona pelúcida. Os ovários apresentaram aspecto morfológico geral semelhante ao de outros peixes teleósteos. Seu tipo de desova foi classificado como intermitente e o padrão de desenvolvimento de ovócitos, como assincrônico.(AU)

The germinal ovarian tissue of the fish Melanotaenia boesemani was studied. By means of morphological analyses of the gonads, performed after the manufacture of histological slides made of paraffin and stained with hematoxylin-eosin, the cell types found were described and the rank of the maturity stage of the fishes was executed. Macroscopically was found that the species has only one ovary, rounded and in the observed phase yellowish, located in the lateral front part of the coelomic cavity. The observed females were classified in the gonadal development scale as mature/in reproduction. The presence of empty follicles and spawning marks on ovigerous lamellae proved to be evident. In vitellogenic oocytes of this fish, the presence of filaments of oocyte adhesion anchored to the pellucida zona was found. The ovaries showed general morphological appearance similar to that of other teleost fishes. Its spawning type was classified as intermittent and the pattern of development of oocytes as asynchronous.(AU)

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This study describes the reproductive strategy of the stream-dwelling catfish Hatcheria macraei in the Pichileufu River, Argentina. Gonad maturity phases, classified on the basis of histological analysis, stages of gamete development and the frequency distribution of oocyte size, were correlated with macroscopic features of the gonads. Hatcheria macraei has a cystovarian ovary, asynchronous oocyte development and lobular testes. Five oocyte and four spermatogenic stages were identified and related to macroscopic gonad characteristics, making it possible to divide gonad development into five phases for females and males. Mature oocyte diameter ranged from 922 to 1935 µm. Absolute fecundity in mature females varied from 115 to 480 oocytes. Hatcheria macraei has multiple spawning during a protracted reproductive season that extends from December to April. This, together with its small size, is characteristic of an opportunistic reproductive strategy, commonly found in species that inhabit adverse and unpredictable environments, such as the low-order rivers of Patagonia.

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Sex determination in vertebrates depends on the expression of a conserved network of genes. Sea turtles such as Lepidochelys olivacea have temperature-dependent sex determination. The present work analyses some of the epigenetic processes involved in this. We describe sexual dimorphism in global DNA methylation patterns between ovaries and testes of L. olivacea and show that the differences may arise from a combination of DNA methylation and demethylation events that occur during sex determination. Irrespective of incubation temperature, 5-hydroxymethylcytosine was abundant in the bipotential gonad; however, following sex determination, this modification was no longer found in pre-Sertoli cells in the testes. These changes correlate with the establishment of the sexually dimorphic DNA methylation patterns, down regulation of Sox9 gene expression in ovaries and irreversible gonadal commitment towards a male or female differentiation pathway. Thus, DNA methylation changes may be necessary for the stabilization of the gene expression networks that drive the differentiation of the bipotential gonad to form either an ovary or a testis in L. olivacea and probably among other species that manifest temperature-dependent sex determination.

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Sublethal toxicity of the formulated fungicide Maxim(®) XL on embryonic, larval and juvenile development of Rhinella arenarum was evaluated by means of standardized bioassays. Maxim(®) XL, one of the most used fungicides in Argentina, is based on a mixture of two active ingredients: Fludioxonil and Metalaxyl-M. Maxim(®) XL exposure induced severe sublethal effects on the embryos, expressed as general underdevelopment, axial flexures, microcephaly, cellular dissociation, abnormal pigmentation, underdeveloped gills, marked edema and wavy tail. As the embryo development advanced, alterations in behavior as spasmodic contractions, general weakness and inanition were observed. Maxim(®) XL did not affect neither the time required to complete metamorphosis nor sex proportions, but gonadal development and differentiation were impaired. Gross gonadal analysis revealed a significant proportion of exposed individuals with underdevelopment of one or both gonads. Histological analysis confirmed that 18% and 10% of the individuals exposed to 0.25 and 2mg/L Maxim(®) XL, respectively, exhibited undifferentiated gonads characterized by a reduced number (or absence) of germ cells. Taking into account the risk evaluation performed by means of Hazard Quotients, this fungicide could be a threat to R. arenarum populations under chronic exposure. This study represents the first evidence of toxic effects exerted by Maxim(®) XL on amphibians. Finally, our findings highlight the properties of this fungicide that might jeopardize non-target living species exposed to it in agricultural environments.

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The germinal ovarian tissue of the fish Melanotaenia boesemani was studied. By means of morphological analyses of the gonads, performed after the manufacture of histological slides made of paraffin and stained with hematoxylin-eosin, the cell types found were described and the rank of the maturity stage of the fishes was executed. Macroscopically was found that the species has only one ovary, rounded and in the observed phase yellowish, located in the lateral front part of the coelomic cavity. The observed females were classified in the gonadal development scale as mature/in reproduction. The presence of empty follicles and spawning marks on ovigerous lamellae proved to be evident. In vitellogenic oocytes of this fish, the presence of filaments of oocyte adhesion anchored to the pellucida zona was found. The ovaries showed general morphological appearance similar to that of other teleost fishes. Its spawning type was classified as intermittent and the pattern of development of oocytes as asynchronous.(AU)

Estudou-se o tecido germinativo ovariano do peixe Melanotaenia boesemani. Por meio de análises morfológicas das gônadas, realizadas após a confecção de lâminas histológicas elaboradas em parafina e coradas com hematoxilina-eosina, foram descritos os tipos celulares encontrados e realizada a classificação do estádio de maturidade dos peixes. Macroscopicamente, foi identificado que a referida espécie possui ovário único, arredondado e, na fase observada, amarelado, localizado na parte látero-anterior da cavidade celomática. As fêmeas analisadas foram classificadas na escala de desenvolvimento gonadal como maduro/em reprodução. A presença de folículos vazios e marcas de desova nas lamelas ovulígeras mostrou-se evidente. Nos ovócitos vitelogênicos deste peixe, foi constatada a presença de filamentos de adesão ovocitária ancorados à zona pelúcida. Os ovários apresentaram aspecto morfológico geral semelhante ao de outros peixes teleósteos. Seu tipo de desova foi classificado como intermitente e o padrão de desenvolvimento de ovócitos, como assincrônico.(AU)

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Atlantirivulus riograndensis (Costa & Lanés, 2009) is a fish registered to the basin of Patos lagoon and the adjacent coastal plains in southern states of Rio Grande do Sul and Santa Catarina, Brazil, found in shallow water courses with that have large quantities of aquatic vegetation and forest edges. The objective of this study was to investigate the reproductive strategy and tactics of this species including the sex ratio, the length at first maturity, spawning type, fecundity and the possible associations among reproduction and abiotic factors. Sampling of specimens occurred in perennial wetlands within the Banhado dos Pachecos wildlife refuge, in the city of Viamão, state of Rio Grande do Sul, Brazil, which is a conservation unit that belongs to an area of environmental protection in the Pampa Biome. The capture of 30 A. riograndensis specimens per month occurred from January to December of 2012. A total of 188 females and 172 males were captured and the total sex ratio was 1:1 in the sampled population. Sexual maturity of the species occurs after 13.59 and 11.92 mm (SL) for females and males, respectively. Both a multiple spawning and a long reproductive period (since August to March) were confirmed by the presence of post-ovulatory follicles that were observed through histological analysis and the values of the gonadosomatic index in females considered spawning capable. The average absolute fecundity of the species is of 19.33 (± 6.18) vitellogenic oocytes in mature ovaries. No significant relationship was found between mean GSI and the abiotic data. Reproductive tactics presented by A. riograndensis indicate a species with an opportunistic reproductive strategy, following the pattern of other species of the Rivulidae family.

Atlantirivulus riograndensis (Costa & Lanés, 2009) é uma espécie de peixe registrada para a bacia da laguna dos Patos e planícies costeiras adjacentes, nos estados do Rio Grande do Sul e sul de Santa Catarina, Brasil, encontrada em corpos d'água rasos, com grande quantidade de vegetação aquática e em bordas de mata. O objetivo deste estudo consistiu em investigar a estratégia e as táticas reprodutivas desta espécie, incluindo a proporção sexual, o comprimento de primeira maturação, o tipo de desova, a fecundidade e possíveis associações entre a reprodução e fatores abióticos. As amostragens de exemplares da espécie ocorreram em um banhado perene no Refúgio da Vida Silvestre Banhado dos Pachecos, município de Viamão, estado do Rio Grande do Sul, Brasil, que constitui uma área de proteção ambiental em uma unidade de conservação no bioma Pampa. A captura de trinta indivíduos de A. riograndensis por mês, ocorreu de janeiro a dezembro de 2012. Foram amostradas 188 fêmeas e 172 machos e a proporção sexual total foi de 1:1 na população amostrada. A maturação sexual da espécie ocorre a partir de 13,59 e 11,92 mm (CP) para fêmeas e machos, respectivamente. As análises histológicas demonstraram uma desova parcelada com a presença de folículos pós-ovulatórios em fêmeas consideradas aptas a desovar e um período reprodutivo longo, de agosto até março, confirmado pelos valores do índice gonadossomático. A fecundidade média absoluta da espécie foi de 19.33 (± 6.18) oócitos vitelogênicos em ovários maduros. Não houve relação significativa entre as médias de IGS e os dados abióticos. As táticas reprodutivas apresentadas por A. riograndensis indicam uma espécie com estratégia reprodutiva oportunista, seguindo o padrão das demais espécies da família Rivulidade.

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Atlantirivulus riograndensis (Costa & Lanés, 2009) is a fish registered to the basin of Patos lagoon and the adjacent coastal plains in southern states of Rio Grande do Sul and Santa Catarina, Brazil, found in shallow water courses with that have large quantities of aquatic vegetation and forest edges. The objective of this study was to investigate the reproductive strategy and tactics of this species including the sex ratio, the length at first maturity, spawning type, fecundity and the possible associations among reproduction and abiotic factors. Sampling of specimens occurred in perennial wetlands within the Banhado dos Pachecos wildlife refuge, in the city of Viamão, state of Rio Grande do Sul, Brazil, which is a conservation unit that belongs to an area of environmental protection in the Pampa Biome. The capture of 30 A. riograndensis specimens per month occurred from January to December of 2012. A total of 188 females and 172 males were captured and the total sex ratio was 1:1 in the sampled population. Sexual maturity of the species occurs after 13.59 and 11.92 mm (SL) for females and males, respectively. Both a multiple spawning and a long reproductive period (since August to March) were confirmed by the presence of post-ovulatory follicles that were observed through histological analysis and the values of the gonadosomatic index in females considered spawning capable. The average absolute fecundity of the species is of 19.33 (± 6.18) vitellogenic oocytes in mature ovaries. No significant relationship was found between mean GSI and the abiotic data. Reproductive tactics presented by A. riograndensis indicate a species with an opportunistic reproductive strategy, following the pattern of other species of the Rivulidae family.(AU)

Atlantirivulus riograndensis (Costa & Lanés, 2009) é uma espécie de peixe registrada para a bacia da laguna dos Patos e planícies costeiras adjacentes, nos estados do Rio Grande do Sul e sul de Santa Catarina, Brasil, encontrada em corpos d'água rasos, com grande quantidade de vegetação aquática e em bordas de mata. O objetivo deste estudo consistiu em investigar a estratégia e as táticas reprodutivas desta espécie, incluindo a proporção sexual, o comprimento de primeira maturação, o tipo de desova, a fecundidade e possíveis associações entre a reprodução e fatores abióticos. As amostragens de exemplares da espécie ocorreram em um banhado perene no Refúgio da Vida Silvestre Banhado dos Pachecos, município de Viamão, estado do Rio Grande do Sul, Brasil, que constitui uma área de proteção ambiental em uma unidade de conservação no bioma Pampa. A captura de trinta indivíduos de A. riograndensis por mês, ocorreu de janeiro a dezembro de 2012. Foram amostradas 188 fêmeas e 172 machos e a proporção sexual total foi de 1:1 na população amostrada. A maturação sexual da espécie ocorre a partir de 13,59 e 11,92 mm (CP) para fêmeas e machos, respectivamente. As análises histológicas demonstraram uma desova parcelada com a presença de folículos pós-ovulatórios em fêmeas consideradas aptas a desovar e um período reprodutivo longo, de agosto até março, confirmado pelos valores do índice gonadossomático. A fecundidade média absoluta da espécie foi de 19.33 (± 6.18) oócitos vitelogênicos em ovários maduros. Não houve relação significativa entre as médias de IGS e os dados abióticos. As táticas reprodutivas apresentadas por A. riograndensis indicam uma espécie com estratégia reprodutiva oportunista, seguindo o padrão das demais espécies da família Rivulidade.(AU)

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Nutrition influences reproductive functions across vertebrates, but the effects of food availability on the functioning of the hypothalamic-pituitary-gonadal (HPG) axis in wild birds and the mechanisms mediating these effects remain unclear. We investigated the influence of chronic food restriction on the HPG axis of photostimulated house finches, Haemorhous mexicanus. Food-restricted birds had underdeveloped testes with smaller seminiferous tubules than ad libitum-fed birds. Baseline plasma testosterone increased in response to photostimulation in ad libitum-fed but not in food-restricted birds. Food availability did not, however, affect the plasma testosterone increase resulting from a gonadotropin-releasing hormone-I (GnRH) or a luteinizing hormone (LH) challenge. The number of hypothalamic GnRH immunoreactive (ir) but not proGnRH-ir perikarya was higher in food-restricted than in ad libitum-fed finches, suggesting inhibited secretion of GnRH. Hypothalamic gonadotropin-inhibitory hormone (GnIH)-ir and neuropeptide Y (NPY)-ir were not affected by food availability. Plasma corticosterone (CORT) was also not affected by food availability, indicating that the observed HPG axis inhibition did not result from increased activity of the hypothalamic-pituitary-adrenal (HPA) axis. This study is among the first to examine multilevel functional changes in the HPG axis in response to food restriction in a wild bird. The results indicate that food availability affects both hypothalamic and gonadal function, but further investigations are needed to clarify the mechanisms by which nutritional signals mediate these effects.

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This study evaluated the influence of different microalgae diets on gonadal tissue maturation in the native oyster Crassostrea gasar in the laboratory, between MarchandMay 2010, totalizing60 days. Ninety-six oysters, collected from anexperimental farm located on Florianópolis/SC,were transferred to the laboratory and maintained in three different diet treatments:Isochrysisgalbana, Chaetocerosmüelleriand a mix diet of both speciesin a 1:1 ratio. The oysters were conditioned in 3Lexperimental units at a water flow rate of 300 mLmin-1and constant aeration. Food was providedin a continuous flow system, at a density of16x104cells mL-1. The mean water temperature andsalinity during the experimental period were 24.36 ± 1.23ºC and 29.4 ± 3.08, respectively. Fortnightly,six oysters randomly sampled from each treatment were examined for histological analysis. The condition index was analyzedat the beginning and the end of the experiment. The initial mean height and weight of the oysters were 68.25 ± 6.73 mm and 60.89 ± 14.19g, respectively, and the final mean height and weight were 69.20 ± 5.97 mm and 70.04 ± 17.42 g, respectively.The sex ratio for the treatments was 1.2 males for each female and 19.5% of the oysters were considered indeterminate. The condition index was not affected by treatmentsandthere was no improvement on the gonadal tissue maturation of the native oyster C. gasarsubjected to different microalgae diets during the conditioning period.(AU)

Este estudo avaliou a influência de diferentes dietas microalgais sobre a maturação do tecido gonádico da ostra nativa Crassostrea gasarem laboratório, entre março e maio de 2010, totalizando60 dias. Noventa e seis ostras, coletadas em cultivo experimental localizado em Florianópolis/SC, foram transferidas para o laboratório e submetidas a três tratamentos de alimentação: Isochrysisgalbana, Chaetocerosmüellerie uma die Este estudo avaliou a influência de diferentes dietas microalgais sobre a maturação do tecido gonádico da ostra nativa Crassostrea gasarem laboratório, entre março e maio de 2010, totalizando60 dias. Noventa e seis ostras, coletadas em cultivo experimental localizado em Florianópolis/SC, foram transferidas para o laboratório e submetidas a três tratamentos de alimentação: Isochrysisgalbana, Chaetocerosmüellerie uma dieta mista das duas espécies na proporção de 1:1. As ostras foram acondicionadas em unidades experimentais de 3 L com vazão de 300 mLmin-1de água e aeração constante. A alimentação foi fornecida em sistema de fluxo contínuo, na densidade de 16x104célulasmL-1. A temperatura e salinidade média da água durante o período experimental foram 24,36 ± 1,23ºC e 29,4 ± 3,08, respectivamente. Quinzenalmente, foram realizadas análises histológicas de seis indivíduos amostrados aleatoriamente de cada tratamento. O índice de condição foi calculado no início e no fim do experimento. A altura e peso inicial das ostras foram68,25 ± 6,73 mm e 60,89 ± 14,19g, respectivamente, e a altura e peso final foram 69,20 ± 5,97 mm e 70,04 ± 17,42 g, respectivamente. A proporção sexual dos tratamentos foi1,2 machos para cada fêmea e 19,5% das ostras foram consideradas indeterminadas. O índice de condição não foi afetado pelos tratamentos e não houve melhora na maturação do tecido gonádico da ostra nativa C. gasar submetida a diferentes dietas microalgais durante o período de acondicionamento.

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This study aimed to describe the gametogenic cycle and reproductive behavior of the population of Iphigenia brasiliana (Lamarck, 1818) in the estuary of the Subaé river, Todos os Santos Bay, Bahia. The bivalves were collected from November 2001 to November 2002. A total of 244 specimens was measured (anteroposterior axis), gutted, fixed, dehydrated and embedded in paraffin. The histology of the gonads was performed by 5 mm thick serial sections of gonadal tissue, and stained with HE. The length at the beginning of gonadal maturation (Lpm) was estimated from the distribution of the relative frequencies of youth and adults, by length class of individuals. The relative frequencies of the sexes at each stage of development were considered together for the analysis of the reproductive behavior of the population, and, separately, to assess the sexual cycle synchrony between males and females. We observed a variation of sizes between 9.1 and 66.6 mm, with a mean length of 50.2 mm. The study showed no significant difference between the sizes of males and females. There was no evidence of gender differentiation in 2.1% of subjects analyzed. 51.6% of subjects were identified as males (M) and 46.3% as females (F), without significant differences among average number of male and female, resulting in the proportion of M:F ratio of 1,1:1. Lpm was estimated at 11.4 mm, but only to achieve average length of 34.4 mm, all subjects were considered adults. We characterized four stages of evolution of gonadal development in females and males. Analysis of different stages allowed the observation of the atresia phenomena and sex reversal in females. The reproductive cycle presents continuous elimination of gametes, with higher reproductive intensities in the months of November 2001 to April 2002 and also in October 2002.

Este estudo teve como objetivos descrever o ciclo gametogênico e o comportamento reprodutivo da população de Iphigenia brasiliana (Lamarck,1818) no estuário do rio Subaé, Baía de Todos os Santos, Bahia. Os bivalves foram coletados de novembro de 2001 a novembro de 2002. Um total de 244 espécimes foi medido (eixo anteroposterior), eviscerado, fixado, desidratado e incluído em parafina. O estudo histológico das gônadas foi realizado através de cortes seriados do tecido gonadal, de 5 mm de espessura, e corados pela HE. O tamanho médio mínimo da primeira maturação sexual (Lpm) foi estimado a partir da distribuição das frequências relativas de jovens e adultos, por classe de comprimento dos indivíduos. As frequências relativas dos sexos em cada estádio de desenvolvimento foram consideradas conjuntamente para a análise do comportamento reprodutivo da população, e, em separado, para avaliar a sincronia do ciclo sexual entre machos e fêmeas. Foi observada uma variação de tamanhos entre 9,1 e 66,6 mm, com comprimento médio de 50,2 mm. O estudo não demonstrou diferença significativa entre os tamanhos de machos e fêmeas. Não foi possível observar a diferenciação de sexos em 2,1% dos indivíduos analisados. 51,6% dos indivíduos foram identificados como machos (M) e 46,3% como fêmeas (F), não sendo constatadas diferenças significativas entre o número médio de machos e fêmeas, resultando numa proporção de M:F de 1,1:1. O Lpm foi estimado em 11,4 mm, mas apenas ao alcançarem comprimento médio de 34,4 mm, todos os indivíduos foram considerados adultos. Foram caracterizados quatro estádios de evolução do desenvolvimento gonadal em fêmeas e machos. A análise dos diferentes estádios permitiu a observação dos fenômenos de atresia e inversão sexual em fêmeas. O ciclo reprodutivo apresentou eliminação contínua de gametas, com maiores intensidades reprodutivas nos meses de novembro de 2001 a abril de 2002 e, também, no mês de outubro de 2002.

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RESUMO

This study aimed to describe the gametogenic cycle and reproductive behavior of the population of Iphigenia brasiliana (Lamarck, 1818) in the estuary of the Subaé river, Todos os Santos Bay, Bahia. The bivalves were collected from November 2001 to November 2002. A total of 244 specimens was measured (anteroposterior axis), gutted, fixed, dehydrated and embedded in paraffin. The histology of the gonads was performed by 5 mm thick serial sections of gonadal tissue, and stained with HE. The length at the beginning of gonadal maturation (Lpm) was estimated from the distribution of the relative frequencies of youth and adults, by length class of individuals. The relative frequencies of the sexes at each stage of development were considered together for the analysis of the reproductive behavior of the population, and, separately, to assess the sexual cycle synchrony between males and females. We observed a variation of sizes between 9.1 and 66.6 mm, with a mean length of 50.2 mm. The study showed no significant difference between the sizes of males and females. There was no evidence of gender differentiation in 2.1% of subjects analyzed. 51.6% of subjects were identified as males (M) and 46.3% as females (F), without significant differences among average number of male and female, resulting in the proportion of M:F ratio of 1,1:1. Lpm was estimated at 11.4 mm, but only to achieve average length of 34.4 mm, all subjects were considered adults. We characterized four stages of evolution of gonadal development in females and males. Analysis of different stages allowed the observation of the atresia phenomena and sex reversal in females. The reproductive cycle presents continuous elimination of gametes, with higher reproductive intensities in the months of November 2001 to April 2002 and also in October 2002.(AU)

Este estudo teve como objetivos descrever o ciclo gametogênico e o comportamento reprodutivo da população de Iphigenia brasiliana (Lamarck,1818) no estuário do rio Subaé, Baía de Todos os Santos, Bahia. Os bivalves foram coletados de novembro de 2001 a novembro de 2002. Um total de 244 espécimes foi medido (eixo anteroposterior), eviscerado, fixado, desidratado e incluído em parafina. O estudo histológico das gônadas foi realizado através de cortes seriados do tecido gonadal, de 5 mm de espessura, e corados pela HE. O tamanho médio mínimo da primeira maturação sexual (Lpm) foi estimado a partir da distribuição das frequências relativas de jovens e adultos, por classe de comprimento dos indivíduos. As frequências relativas dos sexos em cada estádio de desenvolvimento foram consideradas conjuntamente para a análise do comportamento reprodutivo da população, e, em separado, para avaliar a sincronia do ciclo sexual entre machos e fêmeas. Foi observada uma variação de tamanhos entre 9,1 e 66,6 mm, com comprimento médio de 50,2 mm. O estudo não demonstrou diferença significativa entre os tamanhos de machos e fêmeas. Não foi possível observar a diferenciação de sexos em 2,1% dos indivíduos analisados. 51,6% dos indivíduos foram identificados como machos (M) e 46,3% como fêmeas (F), não sendo constatadas diferenças significativas entre o número médio de machos e fêmeas, resultando numa proporção de M:F de 1,1:1. O Lpm foi estimado em 11,4 mm, mas apenas ao alcançarem comprimento médio de 34,4 mm, todos os indivíduos foram considerados adultos. Foram caracterizados quatro estádios de evolução do desenvolvimento gonadal em fêmeas e machos. A análise dos diferentes estádios permitiu a observação dos fenômenos de atresia e inversão sexual em fêmeas. O ciclo reprodutivo apresentou eliminação contínua de gametas, com maiores intensidades reprodutivas nos meses de novembro de 2001 a abril de 2002 e, também, no mês de outubro de 2002.(AU)

Assuntos