RESUMO

Although the tambaqui (Colossoma macropomum) is the most cultivated native fish species in Brazil, estimated breeding values for growth traits are rarely used for selection of superior individuals in commercial fingerling production. This study aimed to estimate the (co)variance components of growth traits. Body weight, length and width of 2500 tambaqui were determined at tagging and at 6 and 12 months after tagging in a commercial breeding programme in Brazil. Heritability estimates were low for traits measured at tagging (0.10 to 0.19) and moderate to high for traits measured at 6 and 12 months (0.23 to 0.81). Common full-sib effects were high at tagging (>73%), low at 6 months and negligible at 12 months. Positive genetic correlations were found among growth traits at 12 months (0.84 to 0.99) and between growth traits at 6 and 12 months (0.80 to 0.92). These results show that animal selection can be performed at 6 months after tagging. Expected genetic gains for growth traits ranged from 8% to 31%. A simulation of the sex ratio was performed, as individuals did not reach sexual maturity during the experimental period. Because of the sexual dimorphism, more accurate heritability estimates were obtained when considering the female proportion to be 90% in the high-weight group. The findings indicate that it is possible to obtain considerable genetic gains in growth by selecting for growth traits. The development of a tool to determine the sex of animals at early stages can improve the response to selection in tambaqui.

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RESUMO

Abstract In this work, the seminal parameters of P. mesopotamicus were evaluated fresh and after cryopreservation, focusing on the sperm variables that affect the rates of fertilization, hatching and post-hatching parameters such as larval survival and morphology. The semen and oocytes from the animals were collected after extrusion, and seminal quality and oocyte fertilization were analyzed. Subsequently, a portion of each semen sample was cryopreserved and, after two days, the oocytes from three new females were fertilized with cryopreserved semen from the males. The analyzes showed that progressive motility, spermatic vigor, motility duration, number of normal sperm and secondary abnormalities were higher in fresh semen than in semen after thawing (P <0.0001). Similarly, fertilization and hatching rates and the percentage of normal and abnormal larvae in fertilized oocytes were higher when fresh semen was used (P <0.0001). The cryopreservation process affected the qualitative parameters of the semen of Piaractus mesopotamicus. The primary abnormality of spermatozoa was the main variable that influenced both fertilization and hatching rates, both in fresh and thawed semen. The second most important variable that influenced, particularly, thawed semen, was the spermatic vigor.

Resumo Neste trabalho, os parâmetros seminais de P. mesopotamicus foram avaliados fresco e após criopreservação, com foco nas variáveis espermáticas ​​que afetam as taxas de fertilização, eclosão e os parâmetros pós-eclosão como a sobrevivência e a morfologia das larvas. Os espermatozoides e os ovócitos dos animais foram coletados após a extrusão, e a qualidade seminal e a fertilização dos ovócitos foram analisados. Posteriormente, uma porção de cada amostra de semen foi criopreservada e, após dois dias, os ovócitos de três novas fêmeas foram fertilizados com semen criopreservado dos machos. As análises mostraram que a motilidade progressiva, o vigor espermático, a duração da motilidade, o número de espermatozoides normais e anormalidades secundárias foram maiores no semen fresco do que no semen após descongelamento (P <0,0001). Da mesma forma, as taxas de fertilização e eclosão e a porcentagem de larvas normais e anormais em ovócitos fertilizados foram maiores quando o semen fresco foi utilizado (P <0,0001). O processo de criopreservação afetou os parâmetros qualitativos do sêmen de Piaractus mesopotamicus . A anormalidade primária dos espermatozoides foi a principal variável que influenciou tanto a taxa de fertilização como a de eclosão, tanto no semen fresco como no semen descongelado. A segunda variável mais importante que influenciou, particularmente, o semen descongelado, foi o vigor espermático.

Assuntos

RESUMO

In this work, the seminal parameters of P. mesopotamicus were evaluated fresh and after cryopreservation, focusing on the sperm variables that affect the rates of fertilization, hatching and post-hatching parameters such as larval survival and morphology. The semen and oocytes from the animals were collected after extrusion, and seminal quality and oocyte fertilization were analyzed. Subsequently, a portion of each semen sample was cryopreserved and, after two days, the oocytes from three new females were fertilized with cryopreserved semen from the males. The analyzes showed that progressive motility, spermatic vigor, motility duration, number of normal sperm and secondary abnormalities were higher in fresh semen than in semen after thawing (P <0.0001). Similarly, fertilization and hatching rates and the percentage of normal and abnormal larvae in fertilized oocytes were higher when fresh semen was used (P <0.0001). The cryopreservation process affected the qualitative parameters of the semen of Piaractus mesopotamicus. The primary abnormality of spermatozoa was the main variable that influenced both fertilization and hatching rates, both in fresh and thawed semen. The second most important variable that influenced, particularly, thawed semen, was the spermatic vigor.

Assuntos

RESUMO

In this work, the seminal parameters of P. mesopotamicus were evaluated fresh and after cryopreservation, focusing on the sperm variables that affect the rates of fertilization, hatching and post-hatching parameters such as larval survival and morphology. The semen and oocytes from the animals were collected after extrusion, and seminal quality and oocyte fertilization were analyzed. Subsequently, a portion of each semen sample was cryopreserved and, after two days, the oocytes from three new females were fertilized with cryopreserved semen from the males. The analyzes showed that progressive motility, spermatic vigor, motility duration, number of normal sperm and secondary abnormalities were higher in fresh semen than in semen after thawing (P 0.0001). Similarly, fertilization and hatching rates and the percentage of normal and abnormal larvae in fertilized oocytes were higher when fresh semen was used (P 0.0001). The cryopreservation process affected the qualitative parameters of the semen of Piaractus mesopotamicus. The primary abnormality of spermatozoa was the main variable that influenced both fertilization and hatching rates, both in fresh and thawed semen. The second most important variable that influenced, particularly, thawed semen, was the spermatic vigor.(AU)

Neste trabalho, os parâmetros seminais de P. mesopotamicus foram avaliados fresco e após criopreservação, com foco nas variáveis espermáticas que afetam as taxas de fertilização, eclosão e os parâmetros pós-eclosão como a sobrevivência e a morfologia das larvas. Os espermatozoides e os ovócitos dos animais foram coletados após a extrusão, e a qualidade seminal e a fertilização dos ovócitos foram analisados. Posteriormente, uma porção de cada amostra de semen foi criopreservada e, após dois dias, os ovócitos de três novas fêmeas foram fertilizados com semen criopreservado dos machos. As análises mostraram que a motilidade progressiva, o vigor espermático, a duração da motilidade, o número de espermatozoides normais e anormalidades secundárias foram maiores no semen fresco do que no semen após descongelamento (P 0,0001). Da mesma forma, as taxas de fertilização e eclosão e a porcentagem de larvas normais e anormais em ovócitos fertilizados foram maiores quando o semen fresco foi utilizado (P 0,0001). O processo de criopreservação afetou os parâmetros qualitativos do sêmen de Piaractus mesopotamicus . A anormalidade primária dos espermatozoides foi a principal variável que influenciou tanto a taxa de fertilização como a de eclosão, tanto no semen fresco como no semen descongelado. A segunda variável mais importante que influenciou, particularmente, o semen descongelado, foi o vigor espermático.(AU)

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The study aimed to analyze the Colossoma macropomum reproductive behavior and quality of the female gametes throughout the reproductive season. The experiment was carried out in Pimenta Bueno - Rondônia State (Northern Brazil) during the reproductive season (2010-2011) using 36 females. Each sampling was performed on a 15 ± 5 days interval. Female gametes were collected by stripping and the following analyses were performed: weight of oocytes released (g); productivity index, fertilization and hatching rate. During the sampling period was verified effect (p < 0.05) of collecting time into the season for oocytes weight, productivity index and fertilization rate. Although the period 3 (December) did not differ significantly from other periods, it showed better parameters for the quality of C. macropomum oocytes.

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RESUMO

The study aimed to analyze the Colossoma macropomum reproductive behavior and quality of the female gametes throughout the reproductive season. The experiment was carried out in Pimenta Bueno - Rondônia State (Northern Brazil) during the reproductive season (2010-2011) using 36 females. Each sampling was performed on a 15 ± 5 days interval. Female gametes were collected by stripping and the following analyses were performed: weight of oocytes released (g); productivity index, fertilization and hatching rate. During the sampling period was verified effect (p < 0.05) of collecting time into the season for oocytes weight, productivity index and fertilization rate. Although the period 3 (December) did not differ significantly from other periods, it showed better parameters for the quality of C. macropomum oocytes.(AU)

O estudo foi conduzido com o objetivo de analisar o comportamento reprodutivo da espécie Colossoma macropomum, quanto à qualidade de seus gametas femininos ao longo da estação reprodutiva. O experimento foi executado em Pimenta Bueno-Rondônia durante a estação reprodutiva do C. macropomum. Utilizaram 36 fêmeas durante a estação de 2010-2011. Cada coleta apresentou um intervalo de 15±5 dias. Através da extrusão foram coletados os gametas femininos e realizadas as seguintes análises ao longo da estação: peso de oócitos liberados (g); índice de produtividade; taxa de fertilização e eclosão. Durante a estação 2010-2011 foi verificado efeito (p < 0,05) de período (coleta) dentro da estação para peso de oócitos, índice de produtividade e taxa de fertilização. Apesar do período 3 (coleta mês de dezembro) não ter diferenciado significativamente de alguns períodos, foi o que apresentou os melhores parâmetros estabelecidos para a qualidade dos oócitos de C. macropomum.(AU)

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RESUMO

BACKGROUND: Over the last ten years, Brazilian fish farming has become more focused, resulting in the development of genetic improvement programmes (GIP) for two South American species Colossoma macropomum (tambaqui) and Pseudoplatystoma reticulatum (cachara). OBJECTIVE: To describe the action plan used for setting up the GIP and to detail the germplasm bank composition. MATERIALS AND METHODS: Semen of both species was collected, frozen and transported between locations in Brazil. To start the programme, full and half-sib families of both species were established from 120 males and 60 females. RESULTS: New species-specific protocols for semen cryopreservation s were established of value to commercial application in fish farming. CONCLUSION: Germplasm banking has enabled the exchange of biological material and reduced the overall GIP costs. Germplasm banking can be very important to the dissemination of the selected genetic material of these species among fish farmers.

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This study aimed at assessing the sperm quality of the Amazon catfish, Leiarius marmoratus ¸ after refrigeration without extenders. After capturing the animals and stripping of semen, the following parameters were analyzed: progressive motility, motility quality score, duration of motility and sperm morphology. An aliquot of fresh semen from each male was kept at room temperature (28 ± 2°C) as a control, for further comparison with cooled semen. The semen from each animal was stored in extenders-free individual syringes. The syringes were kept in ice within polystyrene boxes at 13 ± 2°C. For both fresh and cooled semen, seminal parameters were evaluated every one-hour interval, reaching seven hours of analysis. Fresh semen showed a significant decrease in motility, motility quality score and duration of motility remaining viable only for three hours. Progressive motility of the cooled semen displayed a negative linear pattern (P<0.05). The duration of motility increased (P<0.05), reaching its peak after three hours of storage. The motility quality score showed a quadratic pattern. No statistical differences were observed when sperm morphology was assessed (P>0.05), even though the mean values of total abnormalities have increased over the storage time. Further studies focusing on the application of this technique should be performed, including the addition of extenders and cryoprotectants for preservation of the sperm over longer periods.(AU)

O objetivo deste experimento foi avaliar a qualidade espermática do Jundiá da Amazônia, Leiarius marmoratus, após resfriamento sem diluidores. Após a captura dos animais e coleta do sêmen, os seguintes parâmetros foram analizados: motilidade progressiva, vigor espermático, duração da motilidade e morfologia espermática. Uma alíquota de sêmen fresco de cada animal foi utilizada como controle, permanecendo em temperatura ambiente (28 ± 2°C) até o momento das análises. O sêmen de cada animal foi armazenado em seringas individuais, sem a presença de diluidores. As seringas foram mantidas em gelo dentro de caixas de poliestireno a uma temperatura media de 13 ± 2°C. Os parâmetros seminais foram avaliados a cada hora, totalizando sete horas de análises. O sêmen fresco (controle) apresentou uma queda significativa na motilidade progressiva, vigor espermático e duração da motilidade, permanecendo viável apenas por três horas. As taxas de motilidade progressiva do sêmen resfriado apresentaram um comportamento linear negativo (P<0.05). Assim como a duração da motilidade aumentou (P<0.05), alcançando seu pico após três horas de resfriamento. O vigor espermático do sêmen resfriado apresentou um comportamento quadrático. Não foi observada diferença estatística na morfologia espermática do sêmen resfriado (P<0.05), embora o número total de anormalidades tende a aumentar com o decorrer do tempo. Estudos adicionais focados na aplicação desta técnica devem ser realizados, incluindo a avaliação de diluidores e crioprotetores para a preservação do sêmen por maiores períodos.(AU)

Assuntos

RESUMO

This study aimed at assessing the sperm quality of the Amazon catfish, Leiarius marmoratus ¸ after refrigeration without extenders. After capturing the animals and stripping of semen, the following parameters were analyzed: progressive motility, motility quality score, duration of motility and sperm morphology. An aliquot of fresh semen from each male was kept at room temperature (28 ± 2°C) as a control, for further comparison with cooled semen. The semen from each animal was stored in extenders-free individual syringes. The syringes were kept in ice within polystyrene boxes at 13 ± 2°C. For both fresh and cooled semen, seminal parameters were evaluated every one-hour interval, reaching seven hours of analysis. Fresh semen showed a significant decrease in motility, motility quality score and duration of motility remaining viable only for three hours. Progressive motility of the cooled semen displayed a negative linear pattern (P<0.05). The duration of motility increased (P<0.05), reaching its peak after three hours of storage. The motility quality score showed a quadratic pattern. No statistical differences were observed when sperm morphology was assessed (P>0.05), even though the mean values of total abnormalities have increased over the storage time. Further studies focusing on the application of this technique should be performed, including the addition of extenders and cryoprotectants for preservation of the sperm over longer periods.

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RESUMO

Cryopreservation of fish gametes has been studied extensively in the last few decades, but the successful cryopreservation of fish embryos remains elusive. However, recent studies using short-term chilling techniques have shown that it is possible to store embryos at low temperatures with no significant loss in viability. Information on cryopreservation of Neotropical freshwater fish embryos has so far been very limited in the literature. In the present study, chilling protocols for storage of pacu embryos at -8°C for up to 24 h were studied using different concentrations of sucrose in methanol. Embryos tolerated the subzero temperature for up to 6 h with no adverse effects (P > 0.05). After 12 h chilling, hatching rate of 64.0 +/- 3.5 percent was recorded. Low temperature storage of pacu embryos by chilling is detailed here for the first time. Further studies are needed to extend the storage time and to improve the hatching rate.

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