RESUMO Para ajustar a frequência alimentar de juvenis de cobia ou beijupirá (Rachycentron canadum), 540 juvenis, com peso médio de 2,0 g (± 0,4) e comprimento médio de 8,7cm (± 0,5), foram distribuídos em quatro tratamentos: T2, T4, T6 e T8 (alimentação realizada duas, quatro, seis e oito vezes ao dia, respectivamente). Cada tratamento teve três repetições. Os juvenis de beijupirá foram alimentados em regime ad libitum. Observou-se diferença significativa no peso final (P<0,05), tendo os peixes do tratamento que receberam ração duas vezes ao dia (T2) apresentado peso significativamente menor do que os peixes que receberam oito refeições ao dia (T8). Não houve diferença nas variáveis conversão alimentar, ganho de peso, comprimento e sobrevivência (P>0,05) entre os tratamentos. Assim, para juvenis de beijupirá, observou-se que a frequência de alimentação de oito refeições por dia, juntamente com um regime de alimentação ad libitum, é a mais adequada durante essa fase. Os dados obtidos no presente experimento permitem otimizar uma etapa da cadeia produtiva do beijupirá.

RESUMO A relação entre o tamanho do pellet da ração e o crescimento dos peixes é bem conhecida na literatura. No entanto, a magnitude dessa associação em relação à eficiência alimentar dos animais ainda não está clara. Portanto, o presente estudo conduzido na Universidade de Virginia Tech (Virginia Seafood Agricultural Research and Extension Center EUA), investigou os efeitos de três tamanhos diferentes de pellets da ração, 1,7 mm (EP.1), 2,3 mm (EP.2) e 3,1 mm (EP.3), sobre o crescimento de juvenis bijupirá (Rachycentron canadum), em um sistema fechado de recirculação. Os animais foram criados por 55 dias, em tanques de 77,5 litros (densidade inicial de 3,78 g / L), pesando 41,83 ± 1,24 g. Os resultados mostraram que, durante o período de cultivo equivalente a oito semanas, não houve diferenças significativas entre o peso final dos peixes para os diferentes tamanhos de pellets (EP.1 - 952,5 ± 40,7 g; EP.2 - 1014,5 ± 26,6 g; EP.3 - 1030,0 ± 54,8 g). No entanto, o ganho de biomassa mostrou diferenças significativas para o maior pellet quando comparado com o menor (EP.1 - 704,0±34+.3 g; EP.2 - 763,0±27,8 g; EP.3 -776,5±51,9 g). Consequentemente, diferenças significativas também foram encontradas nos fatores de conversão alimentar.

ABSTRACT It is known that there is a close relationship between pellet feed size and fish growth. However, the magnitude of this relationship regarding an animals’ feed efficiency is not yet clear. Therefore, the present study conducted at the Virginia Tech - Virginia Seafood Agricultural Research and Extension Center (USA), investigated the effects of three different pellet feed sizes, 1.7mm (EP.1), 2.3 mm (EP.2) and 3.1 mm (EP.3), on the growth of Cobia (Rachycentron canadum) in a recirculating aquaculture system (RAS). Animals were farmed for 55 days in 77.5-liter tanks (6 fish with an initial density of 3.78 g L⁻¹) weighing approximately 41.83±1.24g. The results showed that during the 8-week culture period, there were no significant differences between the animal’s final weight over the different pellet feed sizes (EP.1 - 952.5±40.7g; EP.2 - 1014.5±26.6g; EP.3 - 1030.0±54.8g). However, biomass gain showed significant differences (EP.1 - 704.0±34+.3g; EP.2 - 763.0±27.8g; EP.3 -776.5±51.9g). Consequently, significant differences were also found in the feed conversion factors.

RESUMEN Rachycentron canadum es un pez con importancia económica en la acuacultura debido a su resistencia a variaciones ambientales, factibilidad de cultivo en confinamiento, altas tasas de crecimiento y buena aceptación de los consumidores. La rentabilidad de su cultivo en jaulas se ve afectada negativamente por la dificultad de implementar cultivos monosexo debido a la aparente semejanza entre los sexos. En este estudio se utilizaron técnicas morfométricas para determinar el dimorfismo sexual mediante el análisis de medidas y la forma de los peces. Se encontraron diferencias entre sexos en la posición de los ojos, labios, aleta pectoral y aleta ventral, y en la forma general del cuerpo. La precisión del sexado de los individuos fue de 75,4 % con distancias y 82,7 % con morfometría geométrica.

ABSTRACT Rachycentron canadum is an economically important fish in aquaculture due to its resistance to environmental variations, the feasibility of culture in confinement, high growth rates, and good acceptance by consumers. The profitability of their cage culture is negatively affected by the difficulty of implementing monosex cultures due to the apparent similarity between sexes. In this study, morphometric techniques were used to determine sexual dimorphism by analyzing measurements and the fish’s shape. Differences were found between the sexes in the position of the eyes, lips, pectoral fin and ventral fin, and the body’s general shape. The sexing precision of the individuals was 75.4 % with distances and 82.7 % with geometric morphometry.

Abstract Aquaculture of cobia (Rachycentron canadum) is still incipient in Brazil, as well as the sale of its meat. However, there is a market demand for this product in the state of Rio de Janeiro. The salting process for the meat of cultivated cobia is a way of preserving and marketing the product for the growers. Thus, the present study aimed to assess the chemical properties of salted cobia meat. Market-sized cobia grown in net-tanks located in Baía de Ilha Grande, Angra dos Reis, Rio de Janeiro, Brazil were used. The fish were eviscerated (gutted), beheaded and lightly flattened. The fillets “charutos” were then subjected to brine salting for 6 days, immersed in saturated brine at refrigeration temperature. After the preparation of the product, analyzes of percent composition, chloride content and lipid profile were performed. The product had high concentrations of protein (20.16%), lipids (19.88%) and 6.56% of total chloride. Lipid profile assessment showed significant percentages of palmitic (6.66%) and oleic (4.99%) acids. Therefore, it is concluded that the salted meat of cobia has good nutritional quality, and the product is a source of palmitic and oleic acids that help preventing cardiovascular diseases and lowering cholesterol levels.

ABSTRACT An innovative aquaculture project involving the thermal seawater effluent of a thermoelectric power plant and a recirculating aquaculture system (RAS) was implemented in the Atacama Desert, the driest in the world located in northern Chile to produce the warm water pelagic fish cobia (Rachycentron canadum Linnaeus, 1766). An experimental land-based fish farm was built consisting of nine independent RAS provided with adequate temperature (28°C) and salinity (32) for cobia growth and overall aquaculture performance. Under these conditions, cobia was raised from egg to an average weight of 4 ± 0.4 kg in 12 months. Growth rates were similarly high for all the batches, and mortalities from weaning up to harvest sizes never exceeded 6%. Besides, no antibiotics were ever used, and no infectious diseases ever detected during the four years experimental phase reported herein. The batches of eggs arrived in Chile in 2012 and 2014. After three years, 12 t of cobia were consistently produced per every eight months’ cycle. During this period, successful reproduction and routine volitional spawning of broodstock were achieved, producing offspring from F1 and F2 generations. The biological potential and economic feasibility of the RAS concept for raising cobia in temperate, desert regions was demonstrated and is described. Farm management, multi-trophic aquaculture, animal welfare, proactive health management, zero water effluent discharge, and total recycling of wastes are also discussed as a means of expanding the concept into a commercial phase.

RESUMO O objetivo do presente trabalho foi desenvolver a carne de bijupirá defumada, assim como avaliar o rendimento, a qualidade bacteriológica, a composição centesimal e a aceitabilidade do produto. Análises microbiológicas de pesquisa de Salmonella sp. e contagens de Staphylococcus aureus, coliformes totais e Escherichia coli foram realizadas. Foi determinada a composição centesimal e realizado o teste de aceitação do produto. O rendimento médio da carne após a salga foi de 83,41%, com base no peso do charuto. A análise microbiológica da carne defumada apresentou-se positiva em apenas uma amostra para Staphylococcus aureus e negativa para as demais bactérias. O produto possui boa qualidade nutricional e alcançou 97% de aceitação para o aspecto global, atingindo média de 6,26 (± 0,99). A carne de bijupirá defumada obteve condições higiênico-sanitárias satisfatórias, boa qualidade nutricional, além de alto índice de aceitação sensorial, destacando-se os atributos textura e sabor. Evidenciou-se, assim, que esse tipo de processo pode ser realizado em escala artesanal ou industrial.

ABSTRACT The objective of the study was to develop the smoked cobia meat and to evaluate the yield, the bacteriological quality, the centesimal composition, and the acceptability of the product. Microbiological analysis of Salmonella sp. and Staphylococcus aureus, total coliforms and Escherichia coli counts were performed. The centesimal composition was determined and the acceptance test was performed. The average yield of the product after salting was 83.41% based on the fish roll weight. The microbiological analysis of the smoked meat showed positive in only one sample for Staphylococcus aureus and negative for the other bacteria. The product has a good nutritional quality and was accepted obtaining 97% for the overall aspect, average of 6.26 (± 0.99). The smoked cobia meat obtained satisfactory hygienic-sanitary conditions, good nutritional quality, besides a high index of sensorial acceptance emphasizing the texture and flavor attributes. Smoked process can be easily carried out on an artisanal or industrial scale.

ABSTRACT: Cobia is one of the most promising warm water aquaculture species. In Brazil, cobia farming began in 2008 in the state of Rio de Janeiro from experimental scale facilities to regular near-shore farms based on fresh/frozen fish diets composed mostly of Sardinella sp. Despite the encouraging results achieved in the promotion of sustainable cobia farming, we advocate the replacement of fresh/frozen fish by a practical formulated feed. This experiment evaluated the zootechnical performance and environmental efficiency of moist and practical formulated feeds in early grow-out phases in the cycle of cobia nearshore cage culture. Four hundred and twenty juvenile cobia (151 ± 7 g) were fed with moist feed and practical formulated feed for 56 days. Biometrics were taken every two weeks and diets were analyzed for proximate composition, fatty acid composition and pellet quality. Although growth performance was equivalent between treatments, feed consumption and feed conversion ratios (FCR) were different (p < 0.05) and varied according to water temperature. Cobia fed moist feed exhibited an FCR two times higher than those fed formulated feed. Elevated settling speed and low floatability contributed to higher heterogeneity and lower efficiency of fish fed moist diet. Nitrogen excretion rate was reduced (64 %) and protein efficiency ratio elevated (27 %) within formulated diet groups in comparison to those fed moist diet (79 % and 15 %, respectively). The fatty acid profile of cobia muscle was similar across the groups. With no negative effects of diet substitution on production performance and improvement of environmental efficiency, this approach can be applied and advocated globally and contribute to the responsible intensification of sustainable marine fish culture.

Resumo: O objetivo deste trabalho foi avaliar diferentes taxas de arraçoamento no desempenho produtivo de bijupirá (Rachycentron canadum) criado em águas salobras. Para o experimento, 1.600 juvenis foram distribuídos em 16 cercados instalados em viveiro, em área estuarina. Foram avaliados quatro diferentes níveis de arraçoamento: 1, 3, 5 e 7% do peso vivo (PV) por dia. Avaliaram-se os seguintes parâmetros de desempenho: sobrevivência, biomassa final, taxa de crescimento específico, ganho de peso diário, conversão alimentar aparente, taxa de eficiência proteica, taxa de eficiência lipídica e índice hepatossomático. A sobrevivência foi superior a 80% em todos os níveis de arraçoamento. A conversão alimentar aparente mais eficiente foi obtida com a taxa de arraçoamento de 5% do PV por dia, que também resultou em melhores valores para o índice hepatossomático. A taxa de 5% do PV por dia proporciona melhor desempenho produtivo para o bijupirá em águas salobras.

Abstract: The objective of this work was to evaluate different feeding rates on the productive performance of cobia (Rachycentron canadum) grown in brackish waters. For the experiment, 1,600 juveniles were distributed in 16 enclosures installed in an estuarine pond. Four different feeding rates were evaluated: 1, 3, 5, and 7% live weight (LW) per day. The following performance parameters were assessed: survival, final biomass, specific growth rate, daily weight gain, apparent feed conversion, protein efficiency rate, lipid efficiency rate, and hepatosomatic index. Survival was greater than 80% at all feeding rates. The most efficient feed conversion rate was obtained with the feeding rate of 5% LW per day, which also resulted in better values for the hepatosomatic index. The rate of 5% LW per day provides a better productive performance for cobia in brackish waters.

RESUMO: A qualidade do pescado está condicionada a diversos fatores, entre eles os métodos de insensibilização. Nesta pesquisa foi utilizado o choque elétrico em diferentes intensidades como método de insensibilização do bijupirá (Rachycentron canadum), e avaliados seus efeitos sobre a qualidade dos peixes resfriados. O experimento foi realizado insensibilizando os peixes com eletrochoque de intensidades de 100, 150 e 200 Volts, e armazenados refrigerados durante 21 dias. Os peixes utilizados foram obtidos de uma piscicultura comercial localizada no litoral norte do estado de São Paulo a cerca de 50km, por via marítima, da cidade de Ubatuba-SP. As variáveis de qualidade dos peixes avaliadas foram características físicas, químicas e sensoriais como medidas dielétricas, índice de Rigor Mortir, pH, textura, cor, avaliação sensorial do frescor, ATP e produtos da degradação. O delineamento experimental utilizado foi um fatorial 6X3, seis tempos de análise e três intensidades de choque elétrico. Foram observadas diferenças significativas (P<0,05) para a maioria das variáveis analisadas, tanto para os tratamentos em relação ao tempo, como também para a influência do tempo de armazenamento dentro de cada tratamento. No entanto, o número de variáveis com significância entre os tratamentos foi menor em relação ao número de variáveis em que houve significância para os tempos de conservação, sendo a interação tempoxtratamento a que obteve significância expressiva dentro dos resultados encontrados. Foram observados os melhores resultados para o tratamento com a intensidade em 150 volts para a maioria das variáveis analisadas em que houve diferenças significativas (p<0,05) entre os tratamentos. Concluiu-se também que o bijupirá pode ser conservado em até sete dias após abate em conservação refrigerada utilizando a eletronarcose como método de insensibilização.

ABSTRACT: Fish quality is conditioned by several factors, among them desensitization methods applied for fish managing and slaughtering. This research used electric shock at different intensities as a desensitization method for cobia (Rachycentron canadum) slaughtering and evaluated its effects over fish quality during refrigerated storage. The experiment was carried out by numbing the fish with electroshock at the intensities of 100, 150 and 200 Volts, and keeping them in refrigerated storage for 21 days. On the cobia, obtained from a commercial fish farm the following physical, chemical and sensorial characteristics as quality variables were evaluated: dielectric properties, rigor index, pH, texture, color, sensorial evaluation of freshness, ATP and degradation catabolites. The experimental design was a 6×3 factorial (6 times of analysis and 3 electroshock intensities). Significant differences (P<0.05) were observed for the analyzed variables, as a consequence of desensitization treatments and of storage time within each treatment. However, the number of variables affected by the treatment was smaller than the number of variables significantly affected by the storage time, and the interaction time×treatment was highly significant within the results reported. The best results for the parameters tested were obtained when the treatment at 150 volts intensity with the majority of analyzed variables held significant differences (P<0.05) among treatments. It was also concluded that cobia can be conserved in refrigerated storage within seven days after slaughtering using electro-narcosis as a method of desensitization.

RESUMO As deformidades esqueléticas são problemas frequentes em populações de peixes cultivados devido, principalmente, a condições abióticas desfavoráveis, nutrição inapropriada e fatores genéticos. Estas podem causar natação errática, diminuição do índice de conversão, do crescimento e do valor no mercado. O objetivo deste relato de caso foi apresentar a ocorrência de deformidades em cobias e garoupas juvenis provenientes de uma fazenda marinha em sistema offshore, em Ilhabela, São Paulo, Brasil. Nove cobias e sete garoupas juvenis, que apresentavam deformidades, foram sujeitos à eutanásia e fixados em formol a 10%. Os espécimes foram registrados, processados e corados com "Alcian Blue" (AB) e “Alizarin Red-S" (ARS) para visualização de tecido cartilaginoso e ósseo, respectivamente. Os peixes foram eviscerados para o exame radiográfico. As deformidades observadas em cobia foram: atrofia do opérculo, desorganização das lamelas branquiais, deformidade do maxilar inferior, cifose e escoliose. As garoupas apresentaram deformidade do maxilar inferior e síndrome de Saddleback. Os peixes deste relato de caso estiveram sob manejo deficiente, alimentados com ração comercial para peixes herbívoros de água doce e sardinhas cozinhadas, alta consanguinidade e ausência de profissionais adequadamente treinados para o manejo dessas espécies. A soma desses fatores influenciou diretamente na aparição dessas deformidades, precisando ser controlados para minimizar a incidência de malformações que tenham impacto econômico para os produtores.

ABSTRACT Skeletal deformities are frequent problems in cultured fish populations due mainly to unfavorable abiotic conditions, inappropriate nutrition, and genetic factors. These may cause erratic swimming, decrease of conversion rate, growth, and market value. The aim of this case report was to present the occurrence of deformities in juvenile cobia and groupers from an offshore marine farm in Ilhabela, São Paulo, Brazil. Nine cobias and seven juvenile groupers, that presented deformities, were euthanized and fixed in 10% formaldehyde. They were tagged, processed, and stained with "Alcian Blue" (AB) and "Alizarin Red-S" (ARS) for visualization of cartilage and bone tissue, respectively. After evisceration, radiographic examination was performed. The deformities observed in cobia were atrophy of the operculum, disorganization of the gill lamellae, deformity of the lower jaw, kyphosis, and scoliosis. Groupers presented lower jaw deformity and saddleback syndrome. The farm studied in this case report had poor management standards, fed commercial feed for freshwater herbivorous fish and cooked sardines, high inbreeding and absence of adequately trained professionals to manage these species. The sum of these factors must have directly influenced the appearance of these deformities. It is necessary to control this situation to minimize the incidence of malformations that have economic impacts to farmers.

Resumo A produção da aquicultura vem crescendo em todo o mundo e o cultivo de peixes marinhos no Brasil é ainda muito recente. Condições intensivas de aquicultura podem causar estresse fisiológico ao organismo do cultivo, o que pode ser avaliado por biomarcadores citogenotóxicos. O objetivo desse estudo foi avaliar o efeito genotóxico das condições de cultivo nos eritrócitos de juvenis de beijupirás Rachycentron canadum usando o ensaio cometa e o ensaio de micronúcleo e outras anormalidades nucleares. Juvenis de beijupirá foram cultivados por 13 semanas em um tanque indoor com circulação aberta de água e em um tanque-rede. O ensaio comera e o ensaio de anormalidades nucleares detectaram um maior dano ao DNA e uma maior frequência de anormalidades nucleares em eritrócitos de peixes cultivados no tanque indoor. Results showed that two methods are complementary. Além disso, beijupirás foram injetados com β-naftoflavona (BNF) nas concentrações de 2mgkg-1 e 10mgkg-1 em condições controladas de laboratório e mantidos por 7 dias em tanques separados para um melhor entendimento dos mecanismos de resposta dessa espécie a uma substância tóxica. O ensaio cometa não detectou nenhuma diferença significativa entre os peixes injetados com BNF e os da condição controle, enquanto que o ensaio das anormalidades nucleares apresentaram diferenças significativas entre peixes injetados com BNF e os do controle. Os danos identificados pelo ensaio cometa são quebras reparáveis na fita do DNA, enquanto que as anormalidades nucleares são permanentes. Possivelmente, o período de de manutenção dos peixes nos tanques após a injeção foi suficiente para limpar a BNF dos organismos e reparar as quebras na fita do DNA. Como os beijupirás parecem responder muito bem a compostos genotóxicos, o ensaio cometa e o ensaio de anormalidades nucleares podem ser ferramentas úteis para monitorar as condições de cultivo.

Abstract Aquaculture production is continuously growing worldwide, and marine fish farming in Brazil is still in its infancy. Intensive farming conditions may cause physiological stress to the cultured organism, which can be evaluated by citogenotoxic biomarkers. The aim of this study was to assess the genotoxic effect of the rearing conditions in red blood cells of juvenile cobia Rachycentron canadum by using comet assay and micronucleus and other nuclear abnormalities assay. Juvenile cobia were reared for 13 weeks in indoor tank with open water circulation and in near shore cage. The comet assay and the nuclear abnormalities assay detected higher DNA damage and higher nuclear abnormalities frequency in erythrocytes of fish reared in the indoor tank. Results showed that two methods are complementary. Additionally, cobia were injected with ß-naphthoflavone (BNF) at concentrations of 2mgkg-1 and 10mgkg-1 in laboratory controlled conditions, and maintained for 7 days in separate tanks to better understand the response mechanisms of this species to a toxic substance. The comet assay did not detect any significant differences between BNF injected and control fish, whereas nuclear abnormalities assay showed significant differences between BNF injected and the control groups. The damages identified by the comet assay are repairable breaks in the DNA strands, whereas nuclear abnormalities may be permanent. Possibly the period of maintenance after injection was enough to clean BNF from the organisms and to repair the breaks in the DNA strands. As cobia seems to respond very well to genotoxic elements, comet assay and nuclear abnormalities assay would be useful tools to monitor farming conditions.

Resumo O objetivo desta pesquisa foi comparar os atributos de qualidade de barrinhas temperadas de beijupirá embaladas a vácuo e em atmosfera modificada (MAP), sob temperatura de refrigeração, bem como estabelecer a mistura de gás mais adequada para manter o frescor do produto e a vida de prateleira mais extensa. As barrinhas temperadas de beijupirá foram empanadas com uma mistura de especiarias desidratadas (salsa, cebola, alho, tomate e bacon), embaladas sob vácuo; 100% aeróbico (controle, na presença do ar atmosférico); MAP1 (15% N2 + 80% CO2 + 5% O2); MAP2 (20% N2 + 70% CO2 + 10% O2), e armazenada a 5°C durante 28 dias. A cada 72 horas, amostras foram retiradas, em triplicata, para as análises microbiológicas (contagem total de bactérias mesófilas, contagem total de bactérias psicrotróficas, Staphylococcus coagulase positiva, Salmonella sp., e coliformes termotolerantes a 45°C) e análises físico-químicas (pH, nitrogênio de bases voláteis totais e trimetilamina). Os resultados mostraram que as barrinhas temperadas de beijupirá permaneceram seguras e com qualidade microbiológica e físico-química por um longo período de tempo quando embalados em atmosfera modificada. O grupo MAP1 (15% N2 + 80% CO2 + 5% O2 ) foi o que apresentou melhor desempenho na manutenção da qualidade e frescor, sendo o mais adequado demonstrando sua viabilidade em garantir a qualidade e maior prazo de validade (28 dias) a 5°C.

Abstract The objective of this research was to compare the quality attributes of seasoned cobia sticks packed under vacuum and using modified atmosphere packaging (MAP) and stored under refrigeration, as well as to establish the most suitable gas mixtures to maintain product freshness and provide an extended shelf life. The seasoned cobia sticks were breaded with a mixture of dehydrated spices (parsley, onion, garlic, tomato and bacon), packaged under vacuum; 100% aerobic package (control, with the presence of atmosphere air); MAP1 (15% N2 + 80% CO2 + 5% O2), and MAP2 (20% N2 + 70% CO2 + 10% O2 ), and stored at 5°C for 28 days. Samples were taken every 72 hours for the microbiological analyses (total mesophilic count, total psychrotrophic count, coagulase positive Staphylococcus, Salmonella sp., and thermotolerant Coliforms at 45°C) and physicochemical analyses (pH, the nitrogen from the total volatile bases, and trimethylamine), all carried out in triplicate. The results showed that the seasoned cobia sticks remained safe and with good microbiological, physical and chemical quality for a longer period when packed in a modified atmosphere. MAP1 (15% N2 + 80% CO2 + 5% O2) was the system showing the best performance in the maintenance of quality and freshness, demonstrating the feasibility of ensuring quality and a longer shelf life (28 days) at 5°C.

RESUMEN Objetivo. Evaluar el efecto de tres dietas sobre el desempeño de juveniles de róbalo (Centropomus undecimalis) mantenidos en estanques de agua dulce. Materiales y métodos. 108 juveniles de róbalo fueron distribuidos homogénea y aleatoriamente en un estanque dividido en 9 corrales de 50 m2. Se suministraron tres dietas (D1: alimento comercial para truchas, 45% de proteína; D2: alimento comercial para cobia, 50% de proteína y D3: pescado fresco, 17.52% de proteína). Los tratamientos experimentales fueron asignados por triplicado y se les suministró cada dieta en dos dosis diarias. Se realizaron biometrías cada 20 días evaluando: peso, talla, relación Longitud-Peso, Factor de Conversión Alimenticia (FCA), Factor de Condición (K), Tasa Específica de Crecimiento (SGR) y supervivencia final; durante 120 días. Los resultados fueron evaluados con un ANOVA a una vía, cuando no se encontraron diferencias (p>0.05) las medias fueron comparadas mediante la prueba de la Mediana de Mood. En caso de significación estadística del ANOVA, se aplicó la prueba de comparación múltiple de Tukey HSD. Resultados. Se encontraron diferencias estadísticas entre los tratamientos, mostrando los mayores crecimientos y rendimientos con D2, con valores de SGR=0.65±0.09 g/día; FCA=3.76 y K=0.81±0.06. La supervivencia fue D1=51.4%, D2=50% y D3=77.8% sin diferir estadísticamente entre las diferentes dietas. Conclusiones. El cultivo de esta especie en estanques de agua dulce con suministro de alimento comercial para cobia es viable en términos de crecimiento y ganancia en peso.

ABSTRACT Objective. To evaluate the effect of three diets on the growth of juvenile common snook (Centropomus undecimalis) maintained in freshwater ponds. Materials and methods. 108 juvenile of common snook were homogenous and randomly distributed in a pond, divided into 9 corrals of 50 m2. Three diets were applied (D1: commercial food for trout, 45% protein; D2: commercial food for cobia, 50% protein and D3: fresh fish, 17.52% protein). The experimental treatments were assigned in triplicate and diets were supplied in two daily doses. Biometrics were performed every 20 days to assess: weight, size, Length-Weight correlation, Feed Conversion Factor (FCA), Condition Factor (K), Specific Growth Rate (SGR) and survival; during 120 days. The results were evaluated with a one-way ANOVA, when differences (p<0.05) were found the means were compared by test Median Mood, otherwise a pos-hoc test was performed (Tukey HSD). Results. Applying the test of Mood Median significant differences were found, showing the highest growth with D2, where values of SGR=0.65±0.09 g/day; FCA=3.76 and K=0.81±0.06. Survival was D1=51.4%, D2=50% and D3=77.8% without inferring statistically among the different diets. Conclusions. The culture of this species in freshwater ponds with commercial food for cobia, is viable in terms of growth and weight gain.

RESUMO O objetivo do presente estudo foi registrar a ocorrência de larva de nematoide da família Raphidascarididae, Hysterothylacium deardorffoverstreetorum, em bijupirá Rachycentron canadum (Linnaeus, 1766), criado e alimentado com ração e "trashfish" em fazendas marinhas localizadas no Rio de Janeiro, Brasil, alertando para possíveis riscos zoonóticos ao se usar esse tipo de alimentação para criação de peixes. Foram necropsiados 15 animais. Os parasitas encontrados foram coletados, fixados e, posteriormente, conservados em álcool a 70°GL, clarificados e identificados. Em todos os animais necropsiados, apenas um espécime estava parasitado com uma larva de Hysterothylacium deardorffoverstreetorum na serosa do fígado do peixe e conclui-se que a presença desse parasita em bijupirá de criação alimentado por "trashfish pode estar associada à alimentação, indicando, assim, um potencial risco zoonótico.

ABSTRACT The aim of this study was to record the occurrence of nematode larvae of the Raphidascarididae family, Hysterothylacium deardorffoverstreetorum in cobia Rachycentron canadum (Linnaeus, 1766) grown and fed with trashfish in marine farms located in Rio de Janeiro, Brazil, warning regarding possible zoonotic risk using this type of food for fish. Fifteen animals were necropsied. Parasites found were collected, fixed and later preserved in alcohol 70°GL, clarified and identified. In all animals necropsied, only one specimen was infested with a Hysterothylacium deardorffoverstreetorum larvae in the serosa of fish liver. It is concluded that the presence of the parasite in cobia culture fed with trashfish may be associated with a potential zoonotic risk.

Worldwide, the growth of marine aquaculture is limited by a number of factors. One of the most important is the development of larviculture protocols to produce adequate numbers of juveniles to stock grow-out systems at a convenient cost. In order to develop a tool to assess the nutritional status of cobia larvae, we have cloned and sequenced the Growth Hormone (GH) from the pituitary gland of adult fish, and examined the ontogenetic expression in embryonic and larval specimens by qPCR, as well as tissue distribution in wild adult animals by RT-PCR. The cobia GH sequence showed similarity to the GH sequence of Coryphaena hippurus (mahi mahi), Seriola dumerili (Greater amberjack) and Seriola quinqueradiata (Yellowtail). GH gene expression was studied in 18 different tissues, but was only detected in the pituitary gland, eyes, gill and red muscle. Expression levels were very low in embryos and in early larvae but just before the first feeding, gene expression increased dramatically (~1000 fold) and remained high for the rest of the collection period (to 300 h post fertilization). This pattern of expression is similar to that seen in other rapidly growing temperate marine fish and underscores the rapid somatic growth that begins with the onset of feeding in cobia.

A nivel mundial, el crecimiento de la acuicultura marina está limitado por una serie de factores. Uno de los más importantes es el desarrollo de protocolos de larvicultura para producir un número adecuado de juveniles para abastecer los sistemas de engorda a un costo conveniente. Con el fin de desarrollar una herramienta para evaluar el estado nutricional de las larvas de cobia, se ha clonado y secuenciado la Hormona de Crecimiento (GH) de la hipófisis de peces adultos, y se examinó la expresión ontogenética en muestras de embriones y larvas por qPCR, así como la distribución en los tejidos en animales adultos silvestres mediante RT-PCR. La secuencia de GH de cobia mostró similitud con la secuencia de GH de Coryphaena hippurus (mahi mahi), Seriola dumerili (mayor medregal) y Seriola quinqueradiata (jurel). La expresión del gen GH se estudió en 18 tejidos diferentes, pero sólo se detectó en la hipófisis, los ojos, branquias y músculo rojo. Los niveles de expresión fueron bajos en los embriones y larvas, pero justo antes de la primera alimentación, la expresión de genes se incrementó dramáticamente (~ 1000 veces) y se mantuvieron altos durante el resto del período de recolección de muestras (300 h después de la fecundación). Este patrón de expresión es similar al observado en otras especies de peces marinos de aguas templadas con rápido crecimiento y se remarca con un rápido crecimiento somático que inicia con la primera alimentación en cobia.