RESUMO O tambaqui, Colossoma macropomum, é uma das espécies mais produzidas na piscicultura brasileira, o que tem impulsionado o desenvolvimento de novas tecnologias para aumentar sua produtividade. O objetivo deste estudo foi avaliar o desempenho da produção de dois estoques de tambaqui de segunda geração melhorada geneticamente para ganho de peso em um sistema de criação semi-intensivo, e avaliar sua influência no custo total de produção. Foram analisados 300 peixes (peso e comprimento padrão inicial médio de 160 g e 17 cm, respectivamente) de duas famílias (A e B, 150 peixes cada). Os peixes foram marcados individualmente com microchips e estocados em um tanque escavado de 800 m2. Para análise econômica, os dados de desempenho obtidos foram extrapolados para uma piscicultura com 10 ha de lâmina d’água, adotando a metodologia Custo Total de Produção. Depois de 270 dias de cultivo, os peixes da família B foram significativamente superiores (p < 0,05) para todos os parâmetros de desempenho analisados (peso final = 1965,0 g; ganho de peso = 1786,7 g; ganho de biomassa = 255,2 kg) e crescimento morfométrico em relação aos peixes da família A (peso final = 1881,0 g; ganho de peso = 1737,5 g; ganho de biomassa: 217,7 kg). As estimativas de custo total de produção indicaram que os peixes da família B permitiriam uma redução de 4% no custo fixo médio e uma redução de 1% no custo médio total de produção.

ABSTRACT Tambaqui, Colossoma macropomum, is one of the most produced species in Brazilian fish farming, which has boosted the development of new technologies to increase its productivity. The aim of this study was to evaluate production performance in two second-generation tambaqui stocks selectively bred for weight gain in a semi-intensive rearing system and assess its influence on total production cost. We analyzed 300 fish (initial mean weight and standard length of 160 g and 17 cm, respectively) of two families (A and B, 150 fish each). The fish were individually marked with microchips and stocked in an 800-m2 excavated pond. For economic analysis, the obtained performance data were extrapolated for a fish farm with a 10-ha pond, adopting the Total Production Cost methodology. After 270 days of farming, the fish from family B were significantly superior (p < 0.05) for all analyzed performance parameters (final weight = 1965.0 g; weight gain = 1786.7 g; biomass gain = 255.2 kg) and morphometric growth in relation to the fish from family A (final weight = 1881.0 g; weight gain = 1737.5 g; biomass gain: 217.7 kg). The total production cost estimations indicated that fish from family B would allow for a 4% reduction in the average fixed cost and a 1% decrease in the total average production cost.

O objetivo deste trabalho foi avaliar o efeito de diferentes crioprotetores na viabilidade de embriões de dourado (Salminus brasiliensis). Foram testadas dez soluções crioprotetoras. Para cada solução, 300 embriões foram selecionados na fase do fechamento do blastóporo, e mais 300 embriões foram utilizados como controle negativo. Após o resfriamento (-8ºC por 6 horas), os embriões foram reidratados diretamente na incubadora até a eclosão. O melhor resultado é obtido com solução crioprotetora com 9% de metanol associado a 17% de sacarose, o que resultou em taxa de eclosão de larvas de 67,06%.

The objective of this work was to evaluate the effect of different cryoprotectants on the viability of dourado (Salminus brasiliensis) embryos. Ten cryoprotectant solutions were tested. For each solution, 300 embryos were selected at the closing of the blastopore stage, and 300 more embryos were used as a negative control. After cooling (-8ºC for 6 hours), the embryos were rehydrated directly in the incubator until hatching. The best result is obtained with the cryoprotectant solution containing 9% methanol associated with 17% sucrose, resulting in a larvae hatching rate of 67.06%.

Los programas de repoblación de ríos vienen siendo usados con mayor frecuencia como métodos de conservación de especies de peces. Sin embargo, la evaluación de procedimientos reproductivos y su influencia en la progenie son necesarias para obtener resultados viables en los ecosistemas impactados negativamente por el hombre. El objetivo de este estudio, fue estimar la contribución reproductiva de una progenie de Brycon orbignyanus usada en programas de repoblación, en el sistema reproductivo seminatural, utilizando el marcador molecular microsatélite. Se analizaron muestras de aleta de 44 reproductores, 69 larvas de 3 días y 70 alevinos de 90 días. No se observó mortalidad de reproductores durante el proceso reproductivo y hubo desova/espermiación en todos los individuos, demostrando la efectividad del sistema seminatural en la preservación física y reproductiva durante los cruzamientos. Los 5 loci utilizados produjeron un total de 14 alelos entre 135 pb y 200 pb, siendo observados 3 alelos (BoM1, BoM5, BoM7 y BoM13) y 2 alelos (BoM2) por locus, presentes en los reproductores y en la progenie (larvas y alevinos). Fue confirmada la presencia de paternidad múltiple con participación de pocos reproductores en la progenie, revelando un proceso de dominancia reproductiva. Fueron observadas diferencias en la contribución reproductiva de larvas y alevinos, demostrando que esta contribución en un mismo lote puede ser diferente entre fases de crecimiento

The stock enhancement programs are being used more frequently as methods of fish conservation. However, the evaluation of reproductive procedures and their influence in the offspring are necessary to obtain viable results in the ecosystems impacted negatively by the man. The aim of this study was to estimate the reproductive contribution of a Brycon orbignyanus offspring used in stock enhancement programs, in the semi-natural reproductive system, using the microsatellite molecular marker. Fin samples of 44 broodstocks, 69 larvae of three days and 70 juvenile of 90 days were analyzed. Mortality of broodstocks was not observed during the reproductive process and there was spawing/spermiation in all the individuals, demonstrating the effectiveness of the seminatural system in the physical and reproductive preservation during the mating. The 5 loci used produced 14 alleles a total between 135 bp and 200 bp, being observed 3 alleles (BoM1, BoM5, BoM7 and BoM13) and 2 alleles (BoM2) by locus present in the broodstocks and in the offspring (larvae and juvenile). The presence of multiple paternity was confirmed with participation of few broodstocks in the offspring, revealing a possible process of reproductive dominance. Differences in the reproductive contribution of larvae and juvenile were observed, demonstrating that this contribution in oneself stock can be different between phases of growth

Los programas de repoblamiento de ríos vienen siendo usados con mayor frecuencia como métodos de conservación de la ictiofauna. Sin embargo, el monitoreo genético y evaluación de procedimientos reproductivos son necesarios para obtener resultados viables en los ecosistemas impactados negativamente por el hombre. El objetivo de este estudio fue analizar la diversidad genética de Brycon orbignyanus utilizado en programas de repoblamiento, en el sistema reproductivo semi-natural (SRSN), con el marcador RAPD. Fueron analizados 15 reproductores (Rp;10 machos y 5 hembras) y 95 larvas de la progenie. El SRSN permitió la obtención de una baja mortalidad de los Rp utilizados en el cruzamiento y todos presentaron desova/espermiación. Los 9 iniciadores utilizados produjeron 90 fragmentos (fg), de los cuales 73,33% fueron polimórficos. Encontrándose diferencias (P<0,05) en la frecuencia de 17 fg, sin la presencia de fg exclusivos. El índice de diversidad genética de Shannon y porcentaje de fg polimórficos fueron inferiores en los individuos de la progenie. La similaridad genética fue mayor en la progenie. El análisis de variancia molecular mostró que la mayor parte de la variación está dentro de cada lote (81,49%) y no entre los lotes (18,51%). La identidad y distancia genética fue 0,953 y 0,049, respectivamente. A pesar que el SRSN permitió la obtención de una baja mortalidad y adecuado comportamiento reproductivo de los Rp, hubo disminución de la variabilidad genética en la progenie por el efecto del bajo número de Rp utilizados durante la reproducción y por la baja variabilidad genética existente entre ellos

The stock enhancement programs are being used more frequently as methods of fish conservation. However, the genetic monitoring and the reproductive procedures evaluation are necessary to achieve viable and reliable results. The purpose of this study was to analyze the genetic diversity of Brycon orbignyanus used in stock enhancement programs, in the semi-natural reproductive system, with the RAPD marker. Fifteen broodstocks (10 male and 5 female) and 95 larvae of the offspring were analyzed. The semi-natural reproductive system allowed the obtaining of a low mortality of the broodstocks using in the mating and all presented spawing/spermiation. The nine primers used yielded 90 fragments, of which 73,33% were polymorphic. Differences (P <0,05) in the frequency of 17 fragments were observed, without the presence of exclusive fragments. The Shannon genetic diversity index and percentage of polymorphic fragments were lower in the offspring individuals. Genetic similarity was higher in the offspring. The analysis of molecular variance results showed that the major part of the genetic variation is within the groups (81,49%) and not between them (18,51%). The identity and genetic distance among the groups were 0,953 and 0,049; respectively. In spite of the semi-natural reproductive system to allow the decrease of mortality and an appropriate reproductive broodstocks behavior, was decrease of the genetic variability in the offspring for the effect of the small number of broodstocks used during the reproduction and for the low existent genetic variability among them