Comparative anatomical studies on the cranial nerves of the fully formed embryos of the Nile tilapia Oreochromis niloticus (Ostiechthyes-Cichlidae). I. Nervus glossopharyngeus / Estudos anatômicos comparativos dos nervos cranianos de embriões totalmente formados da tilápia do Nilo Oreochromis niloticus (Ostiechthyes Cichlidae). I. Nervus glossopharyngeus

The organization of the roots, ganglia and the peripheral distribution of the cranial nerves of the fully formed embryos of Oreochromis niloticus are examined in the transverse serial sections. These nerves carry fibers, which were also analyzed. The results of this study demonstrated that the glossopharyngeal nerve originates by means of only one root, which leaves the cranium through the glossopharyngeal foramen. This nerve gives fibers (visceromotor) to the first internal and external levator arcus branchialis muscles. There is a single epibranchial (petrosal) ganglion located extracranially. Nervus glossopharyngeus has three rami; pharyngeus, pretramticus and posttrematicus. The ramus pharyngeus carries only viscerosensory fibers; general for the pharyngeal epithelium and special ones for the pseudobranch. General viscerosensory fibers are also carried by rami pretrematicus and posttrematicus for the pharyngeal epithelial lining. The special sensory fibers are carried by the ramus pretrematicus for the taste buds and by ramus posttrematicus for the gill filaments. The ramus pretrematicus also carries visceromotor fibers for the first adductor arcus branchialis and to the first obliquus ventralis muscles.

A organização das raízes, gânglios e a distribuição periférica dos nervos cranianos dos embriões totalmente formados de Oreochromis niloticus são examinados nas seções transversais seriais. Esses nervos carregam fibras, que também foram analisadas. Os resultados deste estudo demonstraram que o nervo glossofaríngeo se origina por meio de apenas uma raiz, que sai do crânio pelo forame glossofaríngeo. Este nervo fornece fibras (visceromotoras) para os primeiros músculos levantadores do arco branquial interno e externo. Existe um único gânglio epibranquial (petroso) localizado extracranialmente. Nervus glossopharyngeus tem três ramos; faríngeo, pretramticus e póstrematicus. O ramo faríngeo contém apenas fibras viscerossensoriais — gerais para o epitélio faríngeo e especiais para o pseudobrânquio. Fibras viscerossensoriais gerais também são transportadas por ramos pretrematicus e posttrematicus para o revestimento epitelial da faringe. As fibras sensoriais especiais são transportadas pelo ramus pretrematicus para as papilas gustativas e pelo ramus posttrematicus para os filamentos branquiais. O ramo pretrematicus também carrega fibras visceromotoras para o primeiro adutor arcus branchialis e para o primeiro músculo oblíquo ventral.

Comparative anatomical studies on the cranial nerves of the fully formed embryos of the Nile tilapia Oreochromis niloticus (Ostiechthyes-Cichlidae). I. Nervus glossopharyngeus / Estudos anatômicos comparativos dos nervos cranianos de embriões totalmente formados da tilápia do Nilo Oreochromis niloticus (Ostiechthyes Cichlidae). I. Nervus glossopharyngeus

The organization of the roots, ganglia and the peripheral distribution of the cranial nerves of the fully formed embryos of Oreochromis niloticus are examined in the transverse serial sections. These nerves carry fibers, which were also analyzed. The results of this study demonstrated that the glossopharyngeal nerve originates by means of only one root, which leaves the cranium through the glossopharyngeal foramen. This nerve gives fibers (visceromotor) to the first internal and external levator arcus branchialis muscles. There is a single epibranchial (petrosal) ganglion located extracranially. Nervus glossopharyngeus has three rami; pharyngeus, pretramticus and posttrematicus. The ramus pharyngeus carries only viscerosensory fibers; general for the pharyngeal epithelium and special ones for the pseudobranch. General viscerosensory fibers are also carried by rami pretrematicus and posttrematicus for the pharyngeal epithelial lining. The special sensory fibers are carried by the ramus pretrematicus for the taste buds and by ramus posttrematicus for the gill filaments. The ramus pretrematicus also carries visceromotor fibers for the first adductor arcus branchialis and to the first obliquus ventralis muscles.(AU)

A organização das raízes, gânglios e a distribuição periférica dos nervos cranianos dos embriões totalmente formados de Oreochromis niloticus são examinados nas seções transversais seriais. Esses nervos carregam fibras, que também foram analisadas. Os resultados deste estudo demonstraram que o nervo glossofaríngeo se origina por meio de apenas uma raiz, que sai do crânio pelo forame glossofaríngeo. Este nervo fornece fibras (visceromotoras) para os primeiros músculos levantadores do arco branquial interno e externo. Existe um único gânglio epibranquial (petroso) localizado extracranialmente. Nervus glossopharyngeus tem três ramos; faríngeo, pretramticus e póstrematicus. O ramo faríngeo contém apenas fibras viscerossensoriais — gerais para o epitélio faríngeo e especiais para o pseudobrânquio. Fibras viscerossensoriais gerais também são transportadas por ramos pretrematicus e posttrematicus para o revestimento epitelial da faringe. As fibras sensoriais especiais são transportadas pelo ramus pretrematicus para as papilas gustativas e pelo ramus posttrematicus para os filamentos branquiais. O ramo pretrematicus também carrega fibras visceromotoras para o primeiro adutor arcus branchialis e para o primeiro músculo oblíquo ventral.(AU)

Multivariate analysis using morphometric and ultrasound information for selection of tilapia (Oreochromis niloticus) breeders

This study evaluated morphometric and ultrasound information of tilapia (O. niloticus) breeders through multivariate analysis. We applied correlation, clustering, and principal component analysis to a dataset composed of information from 222 male and female breeders of the improved GIFT strain. The body weight, objective of the breeding program, showed a high positive correlation with most of the morphometric parameters. The formation of clusters indicated characteristics responsible for muscle composition and carcass weight. Some characteristics showed a high correlation, such as body weight and fillet weight (0.98 and 0.94 for females and males, respectively), and a high contribution to the explanation of data variability; of the total characteristics evaluated for females, two explained 75% data variability and four explained 72% for males. We concluded that it is possible to reduce the number of characteristics measured, as well as use information of average daily weight gain and body weight to select female and male breeders, respectively, to drive genetic gains favoring more productive generations.(AU)

Induced reproduction and early development histology of Oscar Astronotus ocellatus (Agassiz, 1831).

Oscar (Astronotus ocellatus) is an important fish from the Amazon Basin that has great potential for fish farming, human consumption, sport fishing and fish keeping. This study aimed to evaluate the effect of two hormonal treatments on the induction of artificial reproduction in broodstock and to describe the histological development of embryos and larvae. Broodstocks were selected and induced using two different hormones: (i) extract of carp pituitary (ECP); and (ii) synthetic human chorionic gonadotropin (hCG). Spawnings were transferred to hatcheries, collected at pre-established times, processed and analysed by histology. Astronotus ocellatus did not respond well to induced reproduction. From 16 couples of breeding fish, only five out of the eight females released oocytes after the hormonal action time, three with hCG and two with ECP; just one male responded positively to hCG. Oscar eggs were oval, and semi-adhesive, the yolk contained granules, and egg diameter was approximately 1.65 ± 0.057 to 1.98 ± 0.038 mm. Development from the initial collection (IC) point until the total absorption of the yolk lasted 315 h, at an average temperature of 27.45 ± 2.13°C. Several events marked embryonic and larval development, including the formation of the optic cup, forebrain, otic vesicle and cephalic divisions. The newly hatched larvae had non-pigmented eyes, and a closed mouth and anus, as well as the presence of adhesive glands on the head. Larval development was characterized by formation of the heart, liver, gaseous bladder, gills, pronephros, brain, fins and also the digestive tract. These results provide important information for the rearing and reproduction of A. ocellatus.

Description of the ontogenic and larval period of discus fish (Symphysodon aequifasciatus).

The aim of this study was to describe the embryonic and larval development of discus fish (Symphysodon aequifasciatus), and to determine the time required, hours post fertilization (hpf), for the emergence of various structures. To describe embryonic and larval stages, observations were made at regular periods under an optical microscope and images were taken with a digital camera attached to a microscope. The average temperature reached in the experimental tank was 27.9°C. Important facts in embryonic and larval development are described, such as the closure of the blastopore, which occurred at 31.5 hpf; a period of eruption, which occurred at 58.5 hpf; and a mouth opening, which occurred at 90.5 hpf; and larvae that exhibited oriented swimming and eating exogenous food at 136.5 hpf.

Genotype by sex interaction at different phases during Nile tilapia culture period / Interação genótipo e sexo em diferentes fases do período de cultivo de tilápias do Nilo

Co(variance) components and genetic parameters were estimated for performance and morphometric traits in male and female Nile tilapia at different growth periods to verify the need for separate selection programs for the two genders. Data set contained information on 1,720 animals, collected in cage system. Two-trait analyses using Bayesian methodology were conducted and the records of males and females were considered distinct traits. Rates of additive genetic variance, phenotypic and heritability were higher for females in estimates for morphometric traits and higher for males in performance traits. Whereas common hatchery environment showed higher relative importance for males, the nursery caused greater variations in females. The reduction of the genetic correlation rates caused by growth increased the difference between genders and indicated the treatment of males and females as a distinct feature selection(AU)

Estimação de componente de co(variância) e parâmetros genéticos foram obtidos para as características de desempenho e morfométricas de machos e fêmeas de tilápias do Nilo em diferentes períodos de cultivo, a fim de verificar a necessidade de programas de seleção distinto para os sexos. O conjunto de dados continha informações de 1.720 animais, coletadas em quatro biometrias e sistema de tanques rede. Realizaram-se análises bicarácter, utilizando a metodologia bayesiana e consideraram-se os registros de machos e fêmeas como características distintas. Os valores de variância genética aditiva, fenotípicas e herdabilidade foram maiores para as fêmeas nas estimavas para as características morfométricas e maiores para os machos nas características de desempenho. Nos machos, o ambiente comum de larvicultura apresentou maior importância relativa. No entanto, nas fêmeas, o ambiente que causou maior variação foi o de alevinagem. As reduções dos valores de correlação genética com o avanço do período de cultivo acentuaram as diferenças entre os sexos e indicaram a necessidade de tratar machos e fêmeas como características de seleções distintos.(AU)

Reproduction performance of female Nile tilapia under different environments and age classes / Performance reprodutiva de fêmeas de tilápias do Nilo em diferentes ambientes e classes de idade

The objective of this work was to verify the reproductive performance of females Nile tilapia in different age classes and reproductive environments. The data set was composed of 451 females evaluated in two different environments in Maringá, PR (hapas of 10 m3, place 1 and hapas of 1 m3, place 2) and in one environment in Alfenas, MG (place 3). The females were separated into three age classes, corresponding to animals with 1 (age 1), 2 (age 2), and 3 years old (age 3). The spawning verification was performed once a week in the period of October/2012 to March/2013, corresponding to 23 weeks of evaluation. The statistical analyses were performed using the Proc Genmod from the statistical program SAS. Place 2 showed the lowest results compared to the other places for multiple spawning, spawning frequency, and volume of eggs/female using animals of age 2. Statistical differences were not observed between ages 1 and 2 considering the same assessment place; however, the age 3 presented at the place 3 showed superior results than females of age 2. Therefore, avoid the use of animals in individual hapas and maintain older females in the squad can improve the reproductive results.

Objetivou-se verificar a performance reprodutivas de fêmeas de tilápia do Nilo em diferentes classes de idade e ambientes reprodutivos. O conjunto de dados foi composto por 451 fêmeas avaliadas em dois ambientes na cidade de Maringá, Estado do Paraná (hapas de 10 m3 - Local 1 e hapas de 1 m3 – Local 2) e em um ambiente em Alfenas, Estado de Minas Gerais (Local 3 – hapas de 14 e 28 m³). As fêmeas foram divididas em três classes de idade, correspondendo a animais de até um (Idade 1), entre um e dois (Idade 2) e com mais de três anos (Idade 3). A verificação de desovas foi realizada uma vez por semana no período de outubro/2012 a março/2013, correspondendo a 23 semanas de avaliação. Realizaram as análises estatísticas utilizando o procedimento Proc Genmod do programa estatístico SAS. O Local 2 apresentou resultados inferiores aos demais locais para todas as características estudadas ao utilizar animais de Idade 2. Diferenças estatísticas não foram observadas entre Idade 1 e 2 para o mesmo local de avaliação, no entanto a Idade 3 presente no Local 3 apresentou resultados superiores ao comparar com fêmeas de Idade 2. Desta forma, evitar o uso de animais em hapas individuais (1 m³) e manter fêmeas mais velhas no plantel podem melhor os resultados reprodutivos.

Genotype by sex interaction at different phases during Nile tilapia culture period / Interação genótipo e sexo em diferentes fases do período de cultivo de tilápias do Nilo

Co(variance) components and genetic parameters were estimated for performance and morphometric traits in male and female Nile tilapia at different growth periods to verify the need for separate selection programs for the two genders. Data set contained information on 1,720 animals, collected in cage system. Two-trait analyses using Bayesian methodology were conducted and the records of males and females were considered distinct traits. Rates of additive genetic variance, phenotypic and heritability were higher for females in estimates for morphometric traits and higher for males in performance traits. Whereas common hatchery environment showed higher relative importance for males, the nursery caused greater variations in females. The reduction of the genetic correlation rates caused by growth increased the difference between genders and indicated the treatment of males and females as a distinct feature selection

Estimação de componente de co(variância) e parâmetros genéticos foram obtidos para as características de desempenho e morfométricas de machos e fêmeas de tilápias do Nilo em diferentes períodos de cultivo, a fim de verificar a necessidade de programas de seleção distinto para os sexos. O conjunto de dados continha informações de 1.720 animais, coletadas em quatro biometrias e sistema de tanques rede. Realizaram-se análises bicarácter, utilizando a metodologia bayesiana e consideraram-se os registros de machos e fêmeas como características distintas. Os valores de variância genética aditiva, fenotípicas e herdabilidade foram maiores para as fêmeas nas estimavas para as características morfométricas e maiores para os machos nas características de desempenho. Nos machos, o ambiente comum de larvicultura apresentou maior importância relativa. No entanto, nas fêmeas, o ambiente que causou maior variação foi o de alevinagem. As reduções dos valores de correlação genética com o avanço do período de cultivo acentuaram as diferenças entre os sexos e indicaram a necessidade de tratar machos e fêmeas como características de seleções distintos.

Reproduction performance of female Nile tilapia under different environments and age classes / Performance reprodutiva de fêmeas de tilápias do Nilo em diferentes ambientes e classes de idade

The objective of this work was to verify the reproductive performance of females Nile tilapia in different age classes and reproductive environments. The data set was composed of 451 females evaluated in two different environments in Maringá, PR (hapas of 10 m3, place 1 and hapas of 1 m3, place 2) and in one environment in Alfenas, MG (place 3). The females were separated into three age classes, corresponding to animals with 1 (age 1), 2 (age 2), and 3 years old (age 3). The spawning verification was performed once a week in the period of October/2012 to March/2013, corresponding to 23 weeks of evaluation. The statistical analyses were performed using the Proc Genmod from the statistical program SAS. Place 2 showed the lowest results compared to the other places for multiple spawning, spawning frequency, and volume of eggs/female using animals of age 2. Statistical differences were not observed between ages 1 and 2 considering the same assessment place; however, the age 3 presented at the place 3 showed superior results than females of age 2. Therefore, avoid the use of animals in individual hapas and maintain older females in the squad can improve the reproductive results.(AU)

Objetivou-se verificar a performance reprodutivas de fêmeas de tilápia do Nilo em diferentes classes de idade e ambientes reprodutivos. O conjunto de dados foi composto por 451 fêmeas avaliadas em dois ambientes na cidade de Maringá, Estado do Paraná (hapas de 10 m3 - Local 1 e hapas de 1 m3 Local 2) e em um ambiente em Alfenas, Estado de Minas Gerais (Local 3 hapas de 14 e 28 m³). As fêmeas foram divididas em três classes de idade, correspondendo a animais de até um (Idade 1), entre um e dois (Idade 2) e com mais de três anos (Idade 3). A verificação de desovas foi realizada uma vez por semana no período de outubro/2012 a março/2013, correspondendo a 23 semanas de avaliação. Realizaram as análises estatísticas utilizando o procedimento Proc Genmod do programa estatístico SAS. O Local 2 apresentou resultados inferiores aos demais locais para todas as características estudadas ao utilizar animais de Idade 2. Diferenças estatísticas não foram observadas entre Idade 1 e 2 para o mesmo local de avaliação, no entanto a Idade 3 presente no Local 3 apresentou resultados superiores ao comparar com fêmeas de Idade 2. Desta forma, evitar o uso de animais em hapas individuais (1 m³) e manter fêmeas mais velhas no plantel podem melhor os resultados reprodutivos.(AU)

Essential oils in Nile tilapia fingerlings fed / Óleos essenciais na alimentação de alevinos de tilápia do Nilo

The use of herbal extracts and essential oils as additives for fish feed have shown great potential, still requiring that the field trials are performed to determine the final use of these compounds. Aiming to evaluate the growth performance of Nile tilapia fingerlings Oreochromis niloticus fed with different levels essential oils, an experiment was conducted in a completely randomized design with 5 treatments and 4 replicates: 0,000, 0,005, 0,010, 0,015 and 0,020% of a commercial blend microencapsulate based on essential oils in the diet. Net tanks with volume of 1m3 were used as experimental units with a stocking density of 50 fingerling m3. At the end of 69 days of culture there was no relation between levels of essential oils and the parameters of survival (%), weight gain (g), growth rate (g/day) and feed conversion. On the other hand there was a quadratic relationship of body protein content for different levels of the commercial blend microencapsulate in the diet with the maximum point estimated at 0,0097% inclusion. Therefore, it is concluded that the levels of essential oils used in this study did not provide evidence of the positive effect on the performance of Nile tilapia fingerlings, mainly as a growth promoter.

A utilização de óleos essenciais e extratos herbais como aditivos para alimentação dos peixes têm demonstrado grande potencial, necessitando ainda que ensaios a campo sejam realizados para se determinar a utilização definitiva destes compostos. Com o objetivo de avaliar o desempenho zootécnico de alevinos de Tilápia do Nilo Oreochromis niloticus alimentados com ração contendo diferentes níveis de óleos essenciais, realizou-se um experimento em delineamento inteiramente casualizado com 5 tratamentos e 4 repetições: 0.000; 0,005; 0,010; 0,015 e 0,020% de um aditivo comercial à base de óleos essenciais na ração. Tanques-rede com volume de 1m3 foram utilizados como unidades experimentais com uma densidade de estocagem de 50 alevinos.m-3. Ao final de 69 dias de cultivo não se verificou uma relação entre os diferentes níveis de óleos essenciais e os parâmetros de sobrevivência (%), ganho em peso (g), taxa de crescimento (g.dia-1) e conversão alimentar aparente (CAA). Por outro lado verificou-se uma relação quadrática para o conteúdo de proteína corporalcom ponto de máximo estimado em 0,0097% de inclusão. Sendo assim, conclui-se que os níveis do aditivo utilizados no presente estudo não forneceram evidências do efeito positivo dos óleos essenciais sobre o desempenho de alevinos de tilápia do Nilo, principalmente como promotor de crescimento.

Essential oils in Nile tilapia fingerlings fed / Óleos essenciais na alimentação de alevinos de tilápia do Nilo

The use of herbal extracts and essential oils as additives for fish feed have shown great potential, still requiring that the field trials are performed to determine the final use of these compounds. Aiming to evaluate the growth performance of Nile tilapia fingerlings Oreochromis niloticus fed with different levels essential oils, an experiment was conducted in a completely randomized design with 5 treatments and 4 replicates: 0,000, 0,005, 0,010, 0,015 and 0,020% of a commercial blend microencapsulate based on essential oils in the diet. Net tanks with volume of 1m3 were used as experimental units with a stocking density of 50 fingerling m3. At the end of 69 days of culture there was no relation between levels of essential oils and the parameters of survival (%), weight gain (g), growth rate (g/day) and feed conversion. On the other hand there was a quadratic relationship of body protein content for different levels of the commercial blend microencapsulate in the diet with the maximum point estimated at 0,0097% inclusion. Therefore, it is concluded that the levels of essential oils used in this study did not provide evidence of the positive effect on the performance of Nile tilapia fingerlings, mainly as a growth promoter.(AU)

A utilização de óleos essenciais e extratos herbais como aditivos para alimentação dos peixes têm demonstrado grande potencial, necessitando ainda que ensaios a campo sejam realizados para se determinar a utilização definitiva destes compostos. Com o objetivo de avaliar o desempenho zootécnico de alevinos de Tilápia do Nilo Oreochromis niloticus alimentados com ração contendo diferentes níveis de óleos essenciais, realizou-se um experimento em delineamento inteiramente casualizado com 5 tratamentos e 4 repetições: 0.000; 0,005; 0,010; 0,015 e 0,020% de um aditivo comercial à base de óleos essenciais na ração. Tanques-rede com volume de 1m3 foram utilizados como unidades experimentais com uma densidade de estocagem de 50 alevinos.m-3. Ao final de 69 dias de cultivo não se verificou uma relação entre os diferentes níveis de óleos essenciais e os parâmetros de sobrevivência (%), ganho em peso (g), taxa de crescimento (g.dia-1) e conversão alimentar aparente (CAA). Por outro lado verificou-se uma relação quadrática para o conteúdo de proteína corporalcom ponto de máximo estimado em 0,0097% de inclusão. Sendo assim, conclui-se que os níveis do aditivo utilizados no presente estudo não forneceram evidências do efeito positivo dos óleos essenciais sobre o desempenho de alevinos de tilápia do Nilo, principalmente como promotor de crescimento.(AU)

Studies on the reproductive and developmental biology of Cichlasoma dimerus (Percifomes, Cichlidae).

Many characteristics of the South American teleost fish Cichlasoma dimerus (body size, easy breeding, undemanding maintenance) make it amenable to laboratory studies. In the last years, many of the fundamental aspects of its reproductive and developmental biology have been addressed in our laboratory. Rather recently, the immunohistochemical localization of pituitary hormones involved in reproduction and in background color adaptation has been described in both adult and developing individuals, and the role of FSH in ovarian differentiation has been established. These findings have been correlated with mapping of some of their brain-derived controlling hormones. The latter include brain-derived gonadotropins which were shown to be active in vitro in the control of pituitary hormone secretions. The emerging picture shows C. dimerus as an interesting species in which many of their basic features have already been investigated and which conform a solid platform for comparative studies correlating neurohormones, pituitary hormones and behavior, from the molecular to the organismic level.

Studies on the reproductive and developmental biology of Cichlasoma dimerus (Percifomes, Cichlidae): [review]

Many characteristics of the South American teleost fish Cichlasoma dimerus (body size, easy breeding, undemanding maintenance) make it amenable to laboratory studies. In the last years, many of the fundamental aspects of its reproductive and developmental biology have been addressed in our laboratory. Rather recently, the immunohistochemical localization of pituitary hormones involved in reproduction and in background color adaptation has been described in both adult and developing individuals, and the role of FSH in ovarian differentiation has been established. These findings have been correlated with mapping of some of their brain-derived controlling hormones. The latter include brain-derived gonadotropins which were shown to be active in vitro in the control of pituitary hormone secretions. The emerging picture shows C. dimerus as an interesting species in which many of their basic features have already been investigated and which conform a solid platform for comparative studies correlating neurohormones, pituitary hormones and behavior, from the molecular to the organismic level.

Studies on the reproductive and developmental biology of Cichlasoma dimerus (Percifomes, Cichlidae): [review]

Many characteristics of the South American teleost fish Cichlasoma dimerus (body size, easy breeding, undemanding maintenance) make it amenable to laboratory studies. In the last years, many of the fundamental aspects of its reproductive and developmental biology have been addressed in our laboratory. Rather recently, the immunohistochemical localization of pituitary hormones involved in reproduction and in background color adaptation has been described in both adult and developing individuals, and the role of FSH in ovarian differentiation has been established. These findings have been correlated with mapping of some of their brain-derived controlling hormones. The latter include brain-derived gonadotropins which were shown to be active in vitro in the control of pituitary hormone secretions. The emerging picture shows C. dimerus as an interesting species in which many of their basic features have already been investigated and which conform a solid platform for comparative studies correlating neurohormones, pituitary hormones and behavior, from the molecular to the organismic level.(AU)

Organogénesis del sistema digestivo del pez Pterophylum scalare (Perciformes: Cichlidae)

Organogenesis of the digestive system of the fish Pterophylum scalare (Perciformes: Cichlidae). There is little knowledge on the development of the angelfish Pterophyllum scalare (Liechtenstein 1823), a species of economical and biological value for inland water ecosystems. We recorded net development time of each organogenetic stage, cumulative time and characteristic structure differentiation for each stage. We found eight organogenetic stages for the digestive system, between the gastrula and the total re-adsorption of the vitelin sack. The total time for the organogenetic development of the digestive system was 119 hours and 44 minutes. Rev. Biol. Trop. 56 (4): 1857-1870. Epub 2008 December 12.

Debido a la poca información sobre el desarrollo de sistemas orgánicos en el pez Pterophylum scalare (Liechtenstein 1823) estudiamos yiempo neto de desarrollo de cada estadio de la organogénesis, tiempo acumulado y diferenciación de estructuras características de cada estadio. Se obtuvo un total de 8 estadios en la organogénesis del sistema digestivo, comprendidos entre la gástrula y la reabsorción total del saco vitelino. La duración de la organogénesis del sistema digestivo fue de 119 horas 44 minutos.

[Organogenesis of the digestive system of the fish Pterophylum scalare (Perciformes: Cichlidae)]. / Organogénesis del sistema digestive del pez Pterophylum scalare (Perciformes: Cichlidae).

There is little knowledge on the development of the angelfish Pterophyllum scalare (Liechtenstein 1823), a species of economical and biological value for inland water ecosystems. We recorded net development time of each organogenetic stage, cumulative time and characteristic structure differentiation for each stage. We found eight organogenetic stages for the digestive system, between the gastrula and the total re-adsorption of the vitelin sack. The total time for the organogenetic development of the digestive system was 119 hours and 44 minutes. Rev.

Efeito da vitamina C sobre o hematócrito e glicemia de alevinos de tilápia-do-nilo (Oreochromis niloticus) em transporte simulado / Effect of vitamin C over the haematocrit and glycemia of nile tilapia (Oreochromis niloticus) alevins in simulated transport

Avaliou-se o efeito do ascorbato sobre o hematócrito e glicemia em alevinos de tilápia nilótica (Oreochromis niloticus) submetidos à simulação de práticas relacionadas ao transporte. Foram utilizadas três dietas experimentais com diferentes níveis de vitamina C (16, 500 e 1000mg de vitamina C/kg), fornecidas durante os 14 dias anteriores à simulação do transporte que se estendeu por 14 horas. O tratamento que continha 16mg de vitamina C/kg foi o que apresentou a glicemia mais elevada logo após a simulação, 108,5mg/dl imediatamente após a simulação e 91mg/dl 12 horas após a simulação. A concentração de 1000mg de vitamina C/kg foi a mais eficiente no controle do aumento da glicemia, 94,6mg/dl imediatamente após a simulação e 74,4mg/dl 12 horas após a simulação. Para a concentração de 500mg de vitamina C/kg foram observados os níveis de 91,4mg/dl imediatamente após a simulação e 103,8mg/dl 12 horas após a simulação. Os valores do hematócrito não apresentaram variação significativa (P>0,05). A suplementação com 1000mg de vitamina C/kg por 14 dias anteriores ao transporte pode ser utilizada de forma profilática em alevinos de tilápia nilótica para amenizar o aumento da glicemia relacionado ao estresse(AU)

The effects of ascorbate on the haematocrit and blood glucose level were evaluated in Nile tilapia alevins (Oreochromis niloticus) submitted to a transport simulation. Three experimental diets with different levels of vitamin C (16, 500 and 1000mg/kg) were given for 14 days before the simulation of the transport. The treatment containing 16mg of vitamin C showed the highest level of glucose after the simulation (108.5mg/dl immediately after the transport and 91mg/dl 12 hours after the transport). The vitamin C concentration of 1000mg/kg was the most efficient treatment to control glycemia increases (94.6mg/dl immediately after the simulation and 74.4mg/dl 12 hour after simulation). In the 500mg/kg treatment, the glucose level was 91.4mg/dl immediately after the simulation and 103.8mg/dl 12 hours after the simulation. The haematocrit values did not show any significative variation (P<0.05). The supplementation with 1000mg/kg of vitamin C for a 14 days period can be used in a prophylactic way to soften glycemia increases in Nile tilapia alevins submitted to transport stress(AU)

Identification of immunoreactive FSH and LH cells in the cichlid fish Cichlasoma dimerus during the ontogeny and sexual differentiation.

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) expressing cells were detected in pituitary, brain and ovary of the Perciform cichlid fish Cichlasoma dimerus. This detection was carried out by immunohistochemistry (IHC) and Western blot techniques using antisera of the Cyprinodontiform Fundulus heteroclitus raised against the conservative region of the teleost betaFSH and the betaLH subunits. The estimated molecular weights were 24 kDa for LH and 19 and 15 kDa for FSH. In the adult pituitary, both cell types were distributed along mid and ventral zones of the proximal pars distalis (PPD, mid-immunoreactive cells), and along the ventral and dorsal external border of the pars intermedia (PI, high-immunoreactive cells). Double IHC showed that FSH and LH are mainly expressed in different pituitary cells. FSH cells were detected in the pituitary around day 21 after hatching (ah) (prior to sex differentiation), while LH cells were detected by day 60 ah (during the sexual differentiation period). A correlation between gonadal sex differentiation and FSH was demonstrated in a 15 days organ culture system. FSH and LH neurons were localized in the nucleus lateralis tuberis and their fibers project through the ventral hypothalamus, preoptic area and neurohypophysis. FSH neurons differentiated on day 21 ah, while LH neurons appeared on day 15 ah. In the ovary, the immunoreactivity for both FSH and LH was restricted to the cytoplasm of previtellogenic and early vitellogenic oocytes.

Gonadal development and sex differentiation in the cichlid fish Cichlasoma dimerus (Teleostei, Perciformes): a light- and electron-microscopic study.

Although the overall pattern and timing of gonadal sex differentiation have been established in a considerable number of teleosts, the ultrastructure of early stages of gonadal development is not well documented. In this study, gonads from larval and juvenile stages of laboratory-reared Cichlasoma dimerus were examined at the light-microscopic and ultrastructural levels. This freshwater species adapts easily to captivity and spawns with high frequency during 8 months of the year, providing an appropriate model for developmental studies. Larvae and juveniles were kept at a water temperature of 26.5 +/- 1 degrees C and a 12:12 hour photoperiod. Gonadal development was documented from 14-100 days postfertilization, covering the period of histologically discernible sex differentiation. Gonadal tissue was processed according to standard techniques for light and electron microscopy. C. dimerus, a perciform teleost, is classified as a differentiated gonochorist, in which an indifferent gonad develops directly into a testis or ovary. On day 14, the gonadal primordium consists of a few germ cells surrounded by enveloping somatic cells. Ovarian differentiation precedes testicular differentiation, as usual in teleost fishes. The earliest signs of differentiation, detected from day 42 onward, include the onset of meiotic activity in newly formed oocytes, which is soon accompanied by increased oogonial mitotic proliferation and the somatic reorganization of the presumptive ovary. The ovarian cavity is completely formed by day 65. Numerous follicles containing perinucleolar oocytes are observed by day 100. In contrast, signs of morphological differentiation in the presumptive testis are not observed until day 72. By day 100, the unrestricted lobular organization of the testis is evident. The latest stage of spermatogenesis observed by this time of testicular development is spermatocyte II.

Melanin-concentrating hormone system in the brain and skin of the cichlid fish Cichlasoma dimerus: anatomical localization, ontogeny and distribution in comparison to alpha-melanocyte-stimulating hormone-expressing cells.

Distribution and development of the melanin-concentrating hormone (MCH) system were examined by immunocytochemistry of the brain, pituitary gland and skin of the South American cichlid fish Cichlasoma dimerus. In adults, the most prominent group of MCH-ir perikarya was located in the nucleus lateralis tuberis (NLT). Outside the NLT, in the posterior hypothalamic region, a group of small neurons was found between the third ventricle and the lateral ventricular recess with delicate immunoreactive fibers that did not seem to contribute to the pituitary innervation. MCH-ir perikarya were identified at day 4 after hatching (AH) in a proliferating zone of the hypothalamic floor. Pituitary innervation could be detected at this stage. Another group of small MCH-ir neurons, only detected in pre-juvenile stages, originated close to the third ventricle in the medial hypothalamic region by day 6 AH. alphaMSH-ir neurons were localized in similar regions of the NLT and in the nucleus periventricularis posterior (NPP). Free MCH-ir neuromasts were detected in the ventral and dorsal skin of larval heads. These epidermal sensory organs were in close association with blood vessels and dermal melanocytes, suggesting that MCH synthesized in larval skin might act in an endocrine way reaching different targets and/or in a paracrine mode regulating melanin concentration in dermal melanocytes.