Embryogenesis of mylossoma duriventre (Pacu-peva) / Embriogênese de mylossoma duriventre (Pacu-peva)

This paper tested a semi-natural reproduction and embryo development of Mylossoma duriventre embryo until hatching. Six females with bulging and softness coelomic cavity and eighteen males that release sperm under light belly compression were selected. Two doses of luteinizing hormone (0.0125 mg/kg and 0.125 mg/kg) were apllied for females performing a semi-natural reproduction.After fertilization the embryos were transferred to an incubator and were evaluated every 15-min intervals during the first hours of development and at one-hour intervals until hatching. The embryos are megalecites with meroblastic division, being visualized six different stages of development: fertilization, cleavage, blastula, gastrula, segmentation and pharyngula. In gastrulation (120-min post-fertilization), there is formation of "tail bud" and appearance of somites during segmentation (510- min post-fertilization), after the blastopore closure. The hatching occurred with 20 hours of development, at a temperature of 24°C. It was possible to reproduce the pacu peva in captivity and the embryonic development showed some specificity when compared to other species. The results of the reproduction and embryogenesis are needed because these are the critical phases that limit the survival of the larvae in fish farming.

Este estudo descreve a reprodução seminatural e o desenvolvimento morfológico de embriões de Mylossoma duriventre até a eclosão. Foram selecionadas seis fêmeas com protuberância e maciez de cavidade celomática e dezoito machos que espermiaram por compressão da cavidade celomática. Foram aplicadas duas doses de hormônio luteinizante (0.0125 mg/kg and 0.125 mg/kg) para fêmeas caracterizando a reprodução semi-natural. Depois da fertilização os embriões foram transferidos para a incubadora e foram avaliados em intervalos de 15 min durante a primeira hora de desenvolvimento e intervalos de uma hora até a eclosão. Os embriões são megalécitos com divisão meroblástica, sendo visualizado seis diferentes estágios de desenvolvimento: fertilização, mórula, blástula, gástrula, segmentação e faringula. Na gastrulação (120min pós fertilização), ocorre a formação do “botão da cauda” e aparecimento dos somitos durante a segmentação (510 min pós fertilização), depois o fechamento de blastóporo. A eclosão ocorreu com 20 horas de desenvolvimento à temperatura de 24ºC. É possível reproduzir pacu-peva em cativeiro e seu desenvolvimento embrionário apresenta especificidades quando comparado com outras espécies. Os resultados em relação à reprodução e a embriogênese são necessários pois, é a fase crítica que limita a sobrevivência das larvas em sistemas produtivos e para o entendimento da biologia da espécie.

Embryogenesis of mylossoma duriventre (Pacu-peva) / Embriogênese de mylossoma duriventre (Pacu-peva)

This paper tested a semi-natural reproduction and embryo development of Mylossoma duriventre embryo until hatching. Six females with bulging and softness coelomic cavity and eighteen males that release sperm under light belly compression were selected. Two doses of luteinizing hormone (0.0125 mg/kg and 0.125 mg/kg) were apllied for females performing a semi-natural reproduction.After fertilization the embryos were transferred to an incubator and were evaluated every 15-min intervals during the first hours of development and at one-hour intervals until hatching. The embryos are megalecites with meroblastic division, being visualized six different stages of development: fertilization, cleavage, blastula, gastrula, segmentation and pharyngula. In gastrulation (120-min post-fertilization), there is formation of "tail bud" and appearance of somites during segmentation (510- min post-fertilization), after the blastopore closure. The hatching occurred with 20 hours of development, at a temperature of 24°C. It was possible to reproduce the pacu peva in captivity and the embryonic development showed some specificity when compared to other species. The results of the reproduction and embryogenesis are needed because these are the critical phases that limit the survival of the larvae in fish farming.(AU)

Este estudo descreve a reprodução seminatural e o desenvolvimento morfológico de embriões de Mylossoma duriventre até a eclosão. Foram selecionadas seis fêmeas com protuberância e maciez de cavidade celomática e dezoito machos que espermiaram por compressão da cavidade celomática. Foram aplicadas duas doses de hormônio luteinizante (0.0125 mg/kg and 0.125 mg/kg) para fêmeas caracterizando a reprodução semi-natural. Depois da fertilização os embriões foram transferidos para a incubadora e foram avaliados em intervalos de 15 min durante a primeira hora de desenvolvimento e intervalos de uma hora até a eclosão. Os embriões são megalécitos com divisão meroblástica, sendo visualizado seis diferentes estágios de desenvolvimento: fertilização, mórula, blástula, gástrula, segmentação e faringula. Na gastrulação (120min pós fertilização), ocorre a formação do “botão da cauda” e aparecimento dos somitos durante a segmentação (510 min pós fertilização), depois o fechamento de blastóporo. A eclosão ocorreu com 20 horas de desenvolvimento à temperatura de 24ºC. É possível reproduzir pacu-peva em cativeiro e seu desenvolvimento embrionário apresenta especificidades quando comparado com outras espécies. Os resultados em relação à reprodução e a embriogênese são necessários pois, é a fase crítica que limita a sobrevivência das larvas em sistemas produtivos e para o entendimento da biologia da espécie.(AU)

Larvae of migratory Characiformes species in an archipelago in the Lower Amazon River

In the Amazon basin, most of the migratory Characiformes species represent an important fishing resource for local people. However, the lack of information about the main areas and periods of reproduction and the importance of certain environments for the maintenance of species may jeopardize the renewal of fish stocks. Thus, the aim was to examine the spatial and seasonal variation in the density of larvae of migratory Characiformes species in an archipelago in the Lower Amazon River and to assess the importance of this environment for the biological recruitment of the studied species. The capture of larvae was carried out in places close to restinga swamps, steep ruts,and inlet areas with a plankton net (300 μm) in monthly sampling from January to December 2013. An analysis of variance was used to verify differences in larval density between seasons and sampling months. A total of 30,997 larvae were captured and showed no significant differences in their distributions between habitats. However, a variationbetween the phases of the hydrological cycle was evident, in which the highest larval concentrations were observed during the flooding (17.72 larvae.10m-3) and the drought (1.33 larvae.10m-3). The study area has a great capacity to assist in the maintenance and renewal of regional fish stocks, as it is an important retention and nursery site for larvae of Characiformes that drift along the main channel of the Amazon River.

Larvae of migratory Characiformes species in an archipelago in the Lower Amazon River

In the Amazon basin, most of the migratory Characiformes species represent an important fishing resource for local people. However, the lack of information about the main areas and periods of reproduction and the importance of certain environments for the maintenance of species may jeopardize the renewal of fish stocks. Thus, the aim was to examine the spatial and seasonal variation in the density of larvae of migratory Characiformes species in an archipelago in the Lower Amazon River and to assess the importance of this environment for the biological recruitment of the studied species. The capture of larvae was carried out in places close to restinga swamps, steep ruts,and inlet areas with a plankton net (300 μm) in monthly sampling from January to December 2013. An analysis of variance was used to verify differences in larval density between seasons and sampling months. A total of 30,997 larvae were captured and showed no significant differences in their distributions between habitats. However, a variationbetween the phases of the hydrological cycle was evident, in which the highest larval concentrations were observed during the flooding (17.72 larvae.10m-3) and the drought (1.33 larvae.10m-3). The study area has a great capacity to assist in the maintenance and renewal of regional fish stocks, as it is an important retention and nursery site for larvae of Characiformes that drift along the main channel of the Amazon River.(AU)

Leporinus elongatus induced spawning using carp pituitary extract or mammalian GnRH analogue combined with dopamine receptor antagonists

Several studies have been developed to support the replacement of the crude carp pituitary extract (CPE) by synthetic products for induced reproduction of South American rheophilic species. However, results have been quite heterogeneous and there is no consensus or a routine use of synthetic products in these species. Thus, the aim of this study was to evaluate the ovulatory process in L. elongatus using different protocols of hormonal induction. Thus, fifteen wild mature females maintained at the Experimental Fish Station, Salto Grande, SP, Brazil were submitted to three different hormonal treatments: CPE (fractioned dose: 0.5 and 5.0 mg kg-1 ); mGnRHa (single dose: 3.5 µg kg-1 ) and mGnRHa (single dose: 5.0 µg kg-1 ). The spawning rate and absolute fecundity were similar among the treatments, but fertility rates were higher for CPE treatment (23.60 ± 9.40) then for mGnRHa treatments (close to or zero zero). Although females ovulated in all treatments, none of them provided viable embryos, showing hatching rates close to zero or zero. Both mGnRHa treatments were more potent for inducing the ovulatory process then CPE treatment, which was evidenced by the fact that the formers showed higher volume density of postovulatory follicles (POF). Accordingly, E2 and 17α-OHP plasma levels were higher for the mGnRHa treated females compared to the CPE one at the time of ovulation. In this study we confirmed previous scientific evidence that, regardless of whether promoting ovulation, the use of conventional CPE and GnRH doses are not appropriate for some South American migratory species, due to the nonattainment of viable embryos. Moreover, we have brought new information about the relationship between reproductive performance and gonadal steroids concentrations using different hormonal therapies, contributing to understand the reasons for Leporinus elongatus embryo loss in induced spawning.

Leporinus elongatus induced spawning using carp pituitary extract or mammalian GnRH analogue combined with dopamine receptor antagonists

Several studies have been developed to support the replacement of the crude carp pituitary extract (CPE) by synthetic products for induced reproduction of South American rheophilic species. However, results have been quite heterogeneous and there is no consensus or a routine use of synthetic products in these species. Thus, the aim of this study was to evaluate the ovulatory process in L. elongatus using different protocols of hormonal induction. Thus, fifteen wild mature females maintained at the Experimental Fish Station, Salto Grande, SP, Brazil were submitted to three different hormonal treatments: CPE (fractioned dose: 0.5 and 5.0 mg kg-1 ); mGnRHa (single dose: 3.5 µg kg-1 ) and mGnRHa (single dose: 5.0 µg kg-1 ). The spawning rate and absolute fecundity were similar among the treatments, but fertility rates were higher for CPE treatment (23.60 ± 9.40) then for mGnRHa treatments (close to or zero zero). Although females ovulated in all treatments, none of them provided viable embryos, showing hatching rates close to zero or zero. Both mGnRHa treatments were more potent for inducing the ovulatory process then CPE treatment, which was evidenced by the fact that the formers showed higher volume density of postovulatory follicles (POF). Accordingly, E2 and 17α-OHP plasma levels were higher for the mGnRHa treated females compared to the CPE one at the time of ovulation. In this study we confirmed previous scientific evidence that, regardless of whether promoting ovulation, the use of conventional CPE and GnRH doses are not appropriate for some South American migratory species, due to the nonattainment of viable embryos. Moreover, we have brought new information about the relationship between reproductive performance and gonadal steroids concentrations using different hormonal therapies, contributing to understand the reasons for Leporinus elongatus embryo loss in induced spawning.(AU)

Effects of cryoprotectants and low temperatures on hatching and abnormal embryo development of Prochilodus lineatus (Characiformes: Prochilodontidae)

This study evaluated the effect of the cryoprotectants and the low temperatures on the embryonic development of Prochilodus lineatus, describing their main morphological alterations. On chilling sensitivity test, the survival rates at the twenty somites stage (20S) were 53.6% at 0ºC, and 100% in 5ºC. To test toxicity, the embryos were exposed to a graded series of 1,2-Propanediol (PROP), dimethyl sulfoxide (Me2SO4) and glycerol (GLY), terminating in a solution of high osmolarity. There was no significant difference in the embryos survival of toxicity test between series of PROP and Me2SO4 in the 6S and 20S. In the cooling protocols, were evaluated the effects of low temperature associated with cryoprotectants. At 5ºC, PROP showed survival rates above 75% in the gastrula stage (G) and above 90% in the 6S and 20S stages. High rates of abnormalities were observed, and the most recurrent were: small bodies, fins presenting uncontrolled cell growth, membrane rupture, and retraction. These results demonstrate the need to use cryoprotectant solutions, even when there is no ice nucleation, and, on the other hand, shows that high cryoprotectant concentrations promote numerous morphological lesions, compromising normal embryonic development.(AU)

Este estudo avaliou os efeitos dos crioprotetores e das baixas temperaturas no desenvolvimento embrionário de Prochilodus lineatus, descrevendo suas principais alterações morfológicas. Nos testes de sensibilidade ao frio, as taxas de sobrevivência, no estágio de vinte somitos (20S), foram de 53,6% a 0ºC e 100% a 5ºC. Nos testes de toxicidade, os embriões foram expostos a uma série graduada dos crioprotetores: 1,2-Propanediol (PROP), dimetilsulfóxido (Me2SO4) e glicerol (GLY), terminando em uma combinação de alta osmolaridade. Não houve diferença significativa na sobrevivência dos embriões nas séries do PROP e Me2SO4 nos estágios de 6S e 20S. Nos protocolos de resfriamento, foram avaliados os efeitos da baixa temperatura associados as séries crioprotetoras. A 5ºC, o PROP apresentou taxas de sobrevivência acima de 75% no estádio de gástrula (G) e acima de 90% nos estádios 6S e 20S. Foram observadas altas taxas de anormalidades sendo as mais recorrentes: corpos pequenos, nadadeiras apresentando crescimento celular descontrolado, ruptura da membrana e retração vitelínica. Estes resultados demonstram a necessidade do uso das soluções crioprotetoras, mesmo não havendo nucleação de gelo e, em contrapartida, demonstra que as elevadas concentrações crioprotetoras promovem numerosas lesões morfológicas, comprometendo o desenvolvimento embrionário.(AU)

Effects of cryoprotectants and low temperatures on hatching and abnormal embryo development of Prochilodus lineatus (Characiformes: Prochilodontidae)

This study evaluated the effect of the cryoprotectants and the low temperatures on the embryonic development of Prochilodus lineatus, describing their main morphological alterations. On chilling sensitivity test, the survival rates at the twenty somites stage (20S) were 53.6% at 0ºC, and 100% in 5ºC. To test toxicity, the embryos were exposed to a graded series of 1,2-Propanediol (PROP), dimethyl sulfoxide (Me2SO4) and glycerol (GLY), terminating in a solution of high osmolarity. There was no significant difference in the embryos survival of toxicity test between series of PROP and Me2SO4 in the 6S and 20S. In the cooling protocols, were evaluated the effects of low temperature associated with cryoprotectants. At 5ºC, PROP showed survival rates above 75% in the gastrula stage (G) and above 90% in the 6S and 20S stages. High rates of abnormalities were observed, and the most recurrent were: small bodies, fins presenting uncontrolled cell growth, membrane rupture, and retraction. These results demonstrate the need to use cryoprotectant solutions, even when there is no ice nucleation, and, on the other hand, shows that high cryoprotectant concentrations promote numerous morphological lesions, compromising normal embryonic development.(AU)

Este estudo avaliou os efeitos dos crioprotetores e das baixas temperaturas no desenvolvimento embrionário de Prochilodus lineatus, descrevendo suas principais alterações morfológicas. Nos testes de sensibilidade ao frio, as taxas de sobrevivência, no estágio de vinte somitos (20S), foram de 53,6% a 0ºC e 100% a 5ºC. Nos testes de toxicidade, os embriões foram expostos a uma série graduada dos crioprotetores: 1,2-Propanediol (PROP), dimetilsulfóxido (Me2SO4) e glicerol (GLY), terminando em uma combinação de alta osmolaridade. Não houve diferença significativa na sobrevivência dos embriões nas séries do PROP e Me2SO4 nos estágios de 6S e 20S. Nos protocolos de resfriamento, foram avaliados os efeitos da baixa temperatura associados as séries crioprotetoras. A 5ºC, o PROP apresentou taxas de sobrevivência acima de 75% no estádio de gástrula (G) e acima de 90% nos estádios 6S e 20S. Foram observadas altas taxas de anormalidades sendo as mais recorrentes: corpos pequenos, nadadeiras apresentando crescimento celular descontrolado, ruptura da membrana e retração vitelínica. Estes resultados demonstram a necessidade do uso das soluções crioprotetoras, mesmo não havendo nucleação de gelo e, em contrapartida, demonstra que as elevadas concentrações crioprotetoras promovem numerosas lesões morfológicas, comprometendo o desenvolvimento embrionário.(AU)

Use of glucose or BTS™ combined with DMSO or methylglycol under two differentfreezing protocols for the cryopreservation of sperm from the common curimatã(Prochilodus brevis)

This study evaluated the effect of glucose orBeltsville Thawing Solution (BTS™) combined withdimethyl sulfoxide (DMSO) or methylglycol (MG)under two different freezing protocols on the kineticsand morphology of cryopreserved Prochilodus brevissperm. The semen samples were diluted using one of fourdifferent treatments (glucose+DMSO, glucose+MG,BTS™+DMSO, and BTS™+MG), loaded into 0.25-mlstraws and subjected to two different freezing processes(programmed freezing machine and dry shipper). After10 days, the semen samples were thawed, and the spermmorphology and kinetics were evaluated. Thephysicochemical parameters of the semen in naturawere similar to those observed in other studies ofCharaciformes, indicating the feasibility of semencryopreservation. Glucose, when used as a diluentwith the cryoprotectant MG (glucose+MG), yieldedhigher percentages of mobile spermatozoa afterfreezing in a dry shipper (76.88 ± 4.84%) and in aprogrammed freezing machine (70.95 ± 1.76%)compared with the combination of glucose and DMSO.Moreover, the glucose+MG treatment yielded a highersperm velocity (curvilinear velocity: 79.52 ± 2.88 µm s-1; straight-line velocity: 45.46 ± 3.01 µm s-1; averagepath velocity: 67.92 ± 3.08 µm s-1) than the otherstudied treatments, and a higher amount of normalsperm (74.56 ± 0.77%) was observed in the semensamples cryopreserved using a programmed freezingmachine. The sperm abnormalities observed included abent tail morphology. Therefore, the use ofglucose+MG in combination with either a dry shipper ora programmed freezing machine is recommended forthe cryopreservation of P. brevis sperm because thesemethods yielded high numbers of motile andmorphologically normal spermatozoa.

Use of glucose or BTS™ combined with DMSO or methylglycol under two differentfreezing protocols for the cryopreservation of sperm from the common curimatã(Prochilodus brevis)

This study evaluated the effect of glucose orBeltsville Thawing Solution (BTS™) combined withdimethyl sulfoxide (DMSO) or methylglycol (MG)under two different freezing protocols on the kineticsand morphology of cryopreserved Prochilodus brevissperm. The semen samples were diluted using one of fourdifferent treatments (glucose+DMSO, glucose+MG,BTS™+DMSO, and BTS™+MG), loaded into 0.25-mlstraws and subjected to two different freezing processes(programmed freezing machine and dry shipper). After10 days, the semen samples were thawed, and the spermmorphology and kinetics were evaluated. Thephysicochemical parameters of the semen in naturawere similar to those observed in other studies ofCharaciformes, indicating the feasibility of semencryopreservation. Glucose, when used as a diluentwith the cryoprotectant MG (glucose+MG), yieldedhigher percentages of mobile spermatozoa afterfreezing in a dry shipper (76.88 ± 4.84%) and in aprogrammed freezing machine (70.95 ± 1.76%)compared with the combination of glucose and DMSO.Moreover, the glucose+MG treatment yielded a highersperm velocity (curvilinear velocity: 79.52 ± 2.88 µm s-1; straight-line velocity: 45.46 ± 3.01 µm s-1; averagepath velocity: 67.92 ± 3.08 µm s-1) than the otherstudied treatments, and a higher amount of normalsperm (74.56 ± 0.77%) was observed in the semensamples cryopreserved using a programmed freezingmachine. The sperm abnormalities observed included abent tail morphology. Therefore, the use ofglucose+MG in combination with either a dry shipper ora programmed freezing machine is recommended forthe cryopreservation of P. brevis sperm because thesemethods yielded high numbers of motile andmorphologically normal spermatozoa.(AU)

Cryopreservation of Prochilodus brevis semen: freezing media and thawing rates / Criopreservação do sêmen de Prochilodus brevis: meios de congelação e taxas de descongelação

Prochilodus brevis is a migratory fish, an important component of its river ecosystem and an appreciated animal in northeastern cuisine. However, human activities have threatened its survival. Thus, researchers have become interested in developing genetic material storage protocols, such as seminal cryopreservation. Therefore, determination of the appropriate freezing media and thawing rate is a fundamental step toward the use of this biotechnology in the production of common curimatã and for reducing risks to the species survival. As such, the aim of the current study was to evaluate the effect of different freezing media and thawing rates on the quality of cryopreserved semen from P. brevis. For this study, males received a single dose of pituitary extract of carp 18 hours before semen collection. The semen samples were diluted in 5% glucose + 10% methyl glycol (MG), 5% glucose + 10% dimethyl sulfoxide (DMSO), 0.9% NaCl + 10% methyl glycol, and 0.9% NaCl + 10% dimethyl sulfoxide, loaded into 0.25-mL straws and frozen in liquid nitrogen vapor. The semen from each treatment was thawed at three different thawing rates: 25 C for 30 sec, 30 C for 16 sec and 40 C for 12 sec. Motility, vitality and morphology analyses were performed by computer-assisted sperm analysis (CASA). The characteristics of the fresh sperm mostly resembled those found in the literature. For the parameter...(AU)

O Prochilodus brevis é um peixe reofílico, importante componente do ecossistema fluvial e apreciado na culinária nordestina. No entanto, ações antrópicas têm ameaçado sua sobrevivência. Desta forma, surge, nos pesquisadores, o interesse no desenvolvimento de protocolos de conservação do material genético, como a criopreservação seminal. Logo, a determinação do meio de congelação e da taxa de descongelação adequados, são passos fundamentais que possibilitarão a utilização dessa biotecnologia na produção de curimatã comum, reduzindo os riscos à sua sobrevivência. Portanto, o objetivo desse trabalho foi avaliar o efeito de diferentes meios de congelação e taxas de descongelação sobre a qualidade do sêmen criopreservado de P. brevis. Para isso, 18 horas antes da coleta de sêmen, os machos receberam dose única de extrato hipofisário de carpa. Cada animal foi sedado com solução à base de eugenol e o sêmen foi coletado. As amostras foram diluídas em quatro meios de congelação (5% Glicose + Metilglicol 10%; 5% Glicose + DMSO 10%; 0,9% NaCl + Metilglicol 10%; 0,9% NaCl + DMSO 10%) envasadas em palhetas de 0,25 mL e congeladas em vapor de nitrogênio líquido. O sêmen foi descongelado após sete dias em três taxas de descongelação: 25 C 30 s-1; 30 C 16 s-1; 40 C 12 s-1. Foram feitas as análises de motilidade, vitalidade e morfologia com auxílio de sistema automatizado de análise seminal...(AU)

Cryopreservation of Prochilodus brevis semen: freezing media and thawing rates / Criopreservação do sêmen de Prochilodus brevis: meios de congelação e taxas de descongelação

Prochilodus brevis is a migratory fish, an important component of its river ecosystem and an appreciated animal in northeastern cuisine. However, human activities have threatened its survival. Thus, researchers have become interested in developing genetic material storage protocols, such as seminal cryopreservation. Therefore, determination of the appropriate freezing media and thawing rate is a fundamental step toward the use of this biotechnology in the production of common curimatã and for reducing risks to the species survival. As such, the aim of the current study was to evaluate the effect of different freezing media and thawing rates on the quality of cryopreserved semen from P. brevis. For this study, males received a single dose of pituitary extract of carp 18 hours before semen collection. The semen samples were diluted in 5% glucose + 10% methyl glycol (MG), 5% glucose + 10% dimethyl sulfoxide (DMSO), 0.9% NaCl + 10% methyl glycol, and 0.9% NaCl + 10% dimethyl sulfoxide, loaded into 0.25-mL straws and frozen in liquid nitrogen vapor. The semen from each treatment was thawed at three different thawing rates: 25 C for 30 sec, 30 C for 16 sec and 40 C for 12 sec. Motility, vitality and morphology analyses were performed by computer-assisted sperm analysis (CASA). The characteristics of the fresh sperm mostly resembled those found in the literature. For the parameter...

O Prochilodus brevis é um peixe reofílico, importante componente do ecossistema fluvial e apreciado na culinária nordestina. No entanto, ações antrópicas têm ameaçado sua sobrevivência. Desta forma, surge, nos pesquisadores, o interesse no desenvolvimento de protocolos de conservação do material genético, como a criopreservação seminal. Logo, a determinação do meio de congelação e da taxa de descongelação adequados, são passos fundamentais que possibilitarão a utilização dessa biotecnologia na produção de curimatã comum, reduzindo os riscos à sua sobrevivência. Portanto, o objetivo desse trabalho foi avaliar o efeito de diferentes meios de congelação e taxas de descongelação sobre a qualidade do sêmen criopreservado de P. brevis. Para isso, 18 horas antes da coleta de sêmen, os machos receberam dose única de extrato hipofisário de carpa. Cada animal foi sedado com solução à base de eugenol e o sêmen foi coletado. As amostras foram diluídas em quatro meios de congelação (5% Glicose + Metilglicol 10%; 5% Glicose + DMSO 10%; 0,9% NaCl + Metilglicol 10%; 0,9% NaCl + DMSO 10%) envasadas em palhetas de 0,25 mL e congeladas em vapor de nitrogênio líquido. O sêmen foi descongelado após sete dias em três taxas de descongelação: 25 C 30 s-1; 30 C 16 s-1; 40 C 12 s-1. Foram feitas as análises de motilidade, vitalidade e morfologia com auxílio de sistema automatizado de análise seminal...

Influence of a large dam and importance of an undammed tributary on the reproductive ecology of the threatened fish matrinxã Brycon orthotaenia Günther, 1864 (Characiformes: Bryconidae) in southeastern Brazil

A total of 312 adults of matrinxã were captured bimonthly, between 2011-2012, in two sites of the rio São Francisco: immediately downstream of the Três Marias Dam (site 1) and in the confluence with the rio Abaeté (site 2). Specimens of Brycon orthotaenia from site 2 presented higher values of total length (32.24 ± 5.70 cm for females and 26.64 ± 3.79 cm for males) and body weight (506.66 ± 332.17 g for females and 267.36 ± 145.84 g for males), when compared with the site 1. In site 2 was registered the highest GSI means (9.97 ± 2.96 for females and 0.93 ± 0.52 for males), compared with the site 1 means. Reproduction period occurred from October to February. Unlike site 2, no spawned females or spent males were captured in site 1. Significant differences were found between females and males in site 2 (χ2 = 26.84, df = 1, P < 0.05). Physical-chemical parameters of the water presented higher values in site 2. The canonical correlation test indicated that the reproduction of males is less susceptible to environmental factors than that of females. These results show that B. orthotaenia finds favourable conditions to reproduction just in site 2.(AU)

Um total de 312 adultos de matrinxã foram capturados bimestralmente entre 2011-2012, em dois pontos do rio São Francisco: imediatamente a jusante da barragem de Três Marias (ponto 1) e na confluência com o rio Abaeté (ponto 2). Exemplares de Brycon orthotaenia do ponto 2 apresentaram maiores valores de comprimento total (32,24 ± 5,70 cm para fêmeas e 26,64 ± 3,79 cm para machos) e peso corporal (506,66 ± 332,17 g para fêmeas e 267,36 ± 145,84 g para machos) quando comparado com peixes do ponto 1. No ponto 2, foi registrado as maiores médias de IGS (9,97 ± 2,96 para fêmeas e 0,93 ± 0,52 para machos) em comparação com o ponto 1. O período reprodutivo ocorreu de outubro a fevereiro. Ao contrário do ponto 2, fêmeas desovadas e machos espermiados não foram capturados no ponto 1. Foram encontradas diferenças significativas entre fêmeas e machos no ponto 2 (χ2 = 26,84, gl = 1, P < 0,05). Parâmetros físico-químicos da água apresentaram maiores valores no ponto 2. A análise de correlação canônica indicou que a reprodução de machos é menos susceptível a fatores ambientais do que de fêmeas. Estes resultados mostram que B. orthotaenia encontra condições favoráveis para a reprodução apenas no ponto 2.(AU)

Toxicity of cryoprotectants on Prochilodus lineatus (Valenciennes, 1837) (curimba) embryos in an experimental incubator (Characiformes: Prochilodontidae)

This paper investigated the effect of cryoprotectant substances on Prochilodus lineatus embryos in an experimental incubator. The prospective study applied combinations of polyvinyl alcohol, hydroxyethyl cellulose, gelatin and fetal bovine serum with dimethyl sulfoxide and ethylene glycol in a new experimental incubator. The morphology of embryos, larval viability and the efficiency of experimental incubators in maintaining the quality of embryos were evaluated. This study demonstrates the efficient association between hydroxyethylcellulose and dimethyl sulfoxide as greater viability (p<0.05) was found for embryos (72.9 ± 23.9%). It should also be noted the permeation of cryoprotectants in embryos through the changes found in chorion diameter, embryo diameter and embryo volume comparing the treatments versus control group (water) (p<0.05), this results can help in future cryopreservation protocols. Although the temperature and oxygenation differed between the usual and experimental incubators (p<0.05), the results showed a high fertilization rate (79.6 ± 13.2%) for experimental incubators (p<0.05) which is sufficient for the maintenance of embryos in a cryoprotective environment and effectively allows experimentation for long periods with cryoprotectant substances. Cryopreservation of fish embryos has not been accomplished yet and new approaches are required for understanding the permeability of teleost embryos, especially in Brazilian native species.(AU)

Este trabalho avaliou o efeito de substâncias crioprotetoras sobre embriões de Prochilodus lineatus em uma incubadora experimental. O estudo aplicou combinações de álcool polivinílico, hidroxietilcelulose, gelatina e soro fetal bovino com dimetilosulfóxido e etilenoglicol em uma nova incubadora experimental. Foram avaliadas a morfologia dos embriões, a viabilidade larval e a eficiência das incubadoras experimentais na manutenção da qualidade dos embriões. Este estudo demonstra a associação eficiente entre hidroxietilcelulose e dimetilsulfóxido pela maior viabilidade (p<0,05) encontrada para os embriões (72,9 ± 23,9%). Deve-se notar também a permeação dos crioprotetores nos embriões através das alterações encontradas no diâmetro córion, diâmetro do embrião e no volume do embrião comparando os tratamentos ao grupo controle (água) (p<0,05), estes resultados podem ajudar em futuros protocolos de criopreservação. Embora a temperatura e a oxigenação diferiram entre as incubadoras comuns e as experimentais (p<0,05), os resultados mostraram elevada taxa de fertilização (79,6 ± 13,2%) para incubadoras experimentais (p<0,05), o que é suficiente para a manutenção de embriões em ambiente crioprotetor e permite efetivamente a experimentação por longos períodos com substâncias crioprotetoras. A criopreservação de embriões de peixes ainda não foi realizada e novas abordagens são necessárias para a compreensão da permeabilidade dos embriões de teleósteos, especialmente em espécies nativas brasileiras.(AU)

O desenvolvimento embrionário da Piapara, Leporinus elongatus (Pisces, Anostomidae), utilizando técnicas de histologia, microscopia eletrônica de varredura e imunológicas empregando marcadores ósseos / The embryonic development of Piapara, Leporinus elongatus (Pisces, Anostomidae), using histological techniques, electron microscopy and immunological techniques using bone markers

O desenvolvimento embrionário dos peixes é de grande importância para a piscicultura e na reintrodução de espécies ameaçadas de extinção em seus ambientes, e seu conhecimento constitui uma importante maneira para minimizar doenças e mortalidades dessas espécies. Com o auxílio de técnicas como a Microscopia Eletrônica de Varredura (MEV) e a imuno-histoquimica para identificar proteínas ósseas, foi possível avaliar as fases de desenvolvimento com mais riqueza de detalhes, facilitando a compreensão de hábitos e da biologia da espécie. Neste trabalho pudemos observar a ontogenia e osteogênese da Piapara (Leporinus elongatus), desde a fecundação até a fase juvenil, sendo evidenciadas estruturas importantes como o tamanho do vitelo, essencial para a nutrição do embrião; o fechamento do blastóporo, evento principal da embriogênese, que indica as taxas de fertilização; a metamorfose, que indica a formação dos primeiros e principais órgãos do animal e a formação de sua estrutura óssea. As Proteínas Ósseas Morfogenéticas (BMP-2 e BMP-4), moléculas essenciais reguladoras no desenvolvimento embrionário e na formação óssea, foram observadas apenas no estádio larval até o período juvenil, não sendo evidenciadas nos estágios anteriores. Os resultados desse trabalho trouxeram novas informações quanto à biologia do desenvolvimento dessa espécie, que certamente poderão auxiliar no aprimoramento de técnicas reprodutivas visando uma melhora na sua produção seja para fins comerciais ou de repovoamento.(AU)

The embryonic development of fishes has great importance in fish culture and on reintroduction of species at risk of extinction into their environment; its knowledge constitutes an important way to minimize diseases and mortality of these species. By using techniques like electron microscopy and immunohistochemistry for bone markers identification, it was possible to evaluate the developmental stages of Leporinus elongatus in more details, helping to clarify the habits and biology of this species. Results showed the ontogeny and ostheogenesis of of Leporinus elongatus this species from fecundation to juvenile, evidencing important structures as size of the yolk, essential to embryo nutrition, the blastopores closure, important event in embryogenesis because it indicates fertilization indexes, and the metamorphosis, which shows the main organs' development including bones. Bone morphogenetic markers 1 and 4, essential regulatory molecules for bone development, had their expression restricted from larva to fry stages, and were not observed in their previous stages. In sum, these results provided new data that may improve reproductive techniques for L. elongatus, and will support commercial and repopulation purposes.(AU)