Sterol profile of Neobenedenia melleni, a marine ectoparasite fish.

Neobenedenia melleni, a marine fish ectoparasite, is responsible for considerable losses in the mariculture industry. In maintaining the parasite's homeostasis, sterols are structural and functional lipids that perform vital functions. Thus, understanding the mechanisms of biosynthesis and the uptake of sterols can reveal potential pharmacological targets. The objective of this work was thereby to characterize the N. melleni sterols. The most abundant sterol found was cholesterol in either its free (47.48 ± 15.93 %) or esterified form. However, its precursors, squalene (3.53 ± 0.92 %) and desmosterol (0.25 ± 0.03 %), were also found, suggesting the uptake of these intermediates from hosts or an unusual active pathway of sterol biosynthesis, which can be further explored as pharmacological targets.

Common moist diet replacement to promote sustainable Cobia Rachycentron canadum (Linnaeus) near - shore farming in Brazil

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.

Common moist diet replacement to promote sustainable Cobia Rachycentron canadum (Linnaeus) near - shore farming in Brazil

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.(AU)

Dietary crude protein levels for juvenile Beta / Níveis de proteína bruta em dietas para juvenis de Beta

The aim of this study was to evaluate the dietary crude protein requirements of juvenile Betta splendens. Isocaloric diets were used with six levels (27, 31, 35, 39, 43 e 47%) of crude protein (CP) in entirely randomised design with four repetitions. Fish with an average weight of 0.11 ± 0.02g were fed three times a day for 30 days. At the end of the experiment were evaluated: survival rate (SR); weight gain (WG); feed intake (FI); protein intake (PI); feed conversion (FC); protein efficiency ratio (PER); and specific growth rate (SGR). For FI, FC and PER, a negative linear effect of dietary CP levels was observed (p < 0.05). A quadratic effect of dietary CP levels for SR, WG and SGR was also observed and the estimated values which maximise the respective parameters were 30.95, 33.13 and 29.55% of CP. Thus, we concluded that the requirement for protein for juvenile Betta splendens is between 30 and 33% CP.

Com o presente estudo objetivou-se avaliar as exigências por proteína bruta para juvenis de Betta splendens. Foram utilizadas dietas isocalóricas com seis níveis de proteína bruta (27, 31, 35, 39, 43 e 47%), em delineamento inteiramente casualizado, com quatro repetições. Peixes com peso médio de 0,11 ± 0,02g foram alimentados três vezes ao dia, por 30 dias. Ao final do experimento avaliou-se: taxa de sobrevivência (TS), ganho de peso (GP), consumo de ração (CR), consumo de proteína (CP), conversão alimentar (CA), taxa de eficiência protéica (TEP) e taxa de crescimento específico (TCE). Para os parâmetros de desempenho produtivo CR, CA e TEP observou-se efeito linear negativo dos níveis de proteína bruta na dieta (p < 0,05). Observou-se efeito quadrático dos níveis de proteína da dieta para TS, GP e TCE, sendo 30,95%, 33,13% e 29,55% de PB os valores estimados para maximizar os respectivos parâmetros de desempenho produtivo. Dessa forma, conclui-se que a exigência por proteína para juvenis de Betta splendens está entre 30 e 33% PB.

Dietary crude protein levels for juvenile Beta / Níveis de proteína bruta em dietas para juvenis de Beta

The aim of this study was to evaluate the dietary crude protein requirements of juvenile Betta splendens. Isocaloric diets were used with six levels (27, 31, 35, 39, 43 e 47%) of crude protein (CP) in entirely randomised design with four repetitions. Fish with an average weight of 0.11 ± 0.02g were fed three times a day for 30 days. At the end of the experiment were evaluated: survival rate (SR); weight gain (WG); feed intake (FI); protein intake (PI); feed conversion (FC); protein efficiency ratio (PER); and specific growth rate (SGR). For FI, FC and PER, a negative linear effect of dietary CP levels was observed (p < 0.05). A quadratic effect of dietary CP levels for SR, WG and SGR was also observed and the estimated values which maximise the respective parameters were 30.95, 33.13 and 29.55% of CP. Thus, we concluded that the requirement for protein for juvenile Betta splendens is between 30 and 33% CP.(AU)

Com o presente estudo objetivou-se avaliar as exigências por proteína bruta para juvenis de Betta splendens. Foram utilizadas dietas isocalóricas com seis níveis de proteína bruta (27, 31, 35, 39, 43 e 47%), em delineamento inteiramente casualizado, com quatro repetições. Peixes com peso médio de 0,11 ± 0,02g foram alimentados três vezes ao dia, por 30 dias. Ao final do experimento avaliou-se: taxa de sobrevivência (TS), ganho de peso (GP), consumo de ração (CR), consumo de proteína (CP), conversão alimentar (CA), taxa de eficiência protéica (TEP) e taxa de crescimento específico (TCE). Para os parâmetros de desempenho produtivo CR, CA e TEP observou-se efeito linear negativo dos níveis de proteína bruta na dieta (p < 0,05). Observou-se efeito quadrático dos níveis de proteína da dieta para TS, GP e TCE, sendo 30,95%, 33,13% e 29,55% de PB os valores estimados para maximizar os respectivos parâmetros de desempenho produtivo. Dessa forma, conclui-se que a exigência por proteína para juvenis de Betta splendens está entre 30 e 33% PB. (AU)

Biofiltering efficiency and productive performance of macroalgae with potential for integrated multi-trophic aquaculture (IMTA) / Eficiência biofiltradora e desempenho produtivo de macroalgas com potencial para aquicultura multi-trófica integrada (AMIT)

Seaweeds have many uses in industry and agriculture and many species have potential for integrated multi-trophic aquaculture (IMTA), since they are efficient in removing nutrients from water. The efficiency of Ulva flexuosa, U. fasciata and Gracilaria birdiae in removing nutrients from enriched water and their productive performance in outdoor tanks were quantified. These seaweeds (50 g; n = 5) were grown in tanks containing 50 L of eutrophic seawater, with a salinity of 30, a temperature of 28.5 ± 2.8 C, an irradiance of 547 ± 458 mol photons m-2 s-1 and aeration. The nutrients levels were recorded daily and when total nitrogen removal was detected, the biomass was measured. After five days of cultivation, more than 98% of NH3 (H = 1.1; P = 0.56) and NO3- (H = 2.7; P = 0.25) and 62.1% of PO43- (H = 0.0; P = 0.90) had been removed from the tanks. However, the mean daily growth rate (4.5 ± 2.5% day-1) and productivity (3.5 ± 1.9 g m-2 day-1) of U. fasciata and G. birdiae were higher than U. flexuosa (-13.6 ± 7.7% day-1; -6.24 ± 2.8 g m-2 day-1; P 0.01), demonstrating that microalga contamination by this species promoted high removal efficiency in the tanks, but a low productive performance. Based on these results, U. fasciata and G. birdiae show a greater potential for use in IMTA to improve water quality and produce biomass.

As macroalgas são utilizadas em diversos setores industriais e agrícolas. Além disso, muitas espécies apresentam potencial para aquicultura multitrófica integrada (AMTI), pois são eficientes na remoção de nutrientes da água. A eficiência biofiltradora e desempenho produtivo das macroalgas Ulva flexuosa, U. fasciata e Gracilaria birdiae e foram quantificados em tanques outdoor. As algas (50 g; n = 5) foram cultivadas em tanques de 50 L, com água eutrofizada, salinidade 30 e temperatura média 28,3 C. Os nutrientes foram monitorados diariamente e a biomassa foi mensurada assim que detectada a extinção do nitrogênio. Após cinco dias de cultivo, mais de 98% de NH3 (H = 1,1; P = 0,56) e de NO3- (H = 2,7; P = 0,25) e 62,1% de PO43- (H = 0,0; P = 0,9) foram removidos dos tanques. Contudo, a taxa de crescimento (% dia-1) e a produtividade (g m-2 dia-1) de U. fasciata e de G. birdiae (4,5 ± 2,5% dia-1; 3,5 ± 1,9 g m-2 dia-1) foram superiores às de U. flexuosa (13,6 ± 7,7% dia-1; 6,2 ± 2,8; P 0,01), cuja contaminação por microalgas contribuiu para elevada eficiência de retirada nos tanques desta espécie, mas baixo desempenho produtivo. Desta forma, U. fasciata e G. birdiae foram indicadas para AMTI tanto para a manutenção da qualidade da água quanto para aproveitamento de biomassa.

Biofiltering efficiency and productive performance of macroalgae with potential for integrated multi-trophic aquaculture (IMTA) / Eficiência biofiltradora e desempenho produtivo de macroalgas com potencial para aquicultura multi-trófica integrada (AMIT)

Seaweeds have many uses in industry and agriculture and many species have potential for integrated multi-trophic aquaculture (IMTA), since they are efficient in removing nutrients from water. The efficiency of Ulva flexuosa, U. fasciata and Gracilaria birdiae in removing nutrients from enriched water and their productive performance in outdoor tanks were quantified. These seaweeds (50 g; n = 5) were grown in tanks containing 50 L of eutrophic seawater, with a salinity of 30, a temperature of 28.5 ± 2.8 C, an irradiance of 547 ± 458 mol photons m-2 s-1 and aeration. The nutrients levels were recorded daily and when total nitrogen removal was detected, the biomass was measured. After five days of cultivation, more than 98% of NH3 (H = 1.1; P = 0.56) and NO3- (H = 2.7; P = 0.25) and 62.1% of PO43- (H = 0.0; P = 0.90) had been removed from the tanks. However, the mean daily growth rate (4.5 ± 2.5% day-1) and productivity (3.5 ± 1.9 g m-2 day-1) of U. fasciata and G. birdiae were higher than U. flexuosa (-13.6 ± 7.7% day-1; -6.24 ± 2.8 g m-2 day-1; P 0.01), demonstrating that microalga contamination by this species promoted high removal efficiency in the tanks, but a low productive performance. Based on these results, U. fasciata and G. birdiae show a greater potential for use in IMTA to improve water quality and produce biomass.(AU)

As macroalgas são utilizadas em diversos setores industriais e agrícolas. Além disso, muitas espécies apresentam potencial para aquicultura multitrófica integrada (AMTI), pois são eficientes na remoção de nutrientes da água. A eficiência biofiltradora e desempenho produtivo das macroalgas Ulva flexuosa, U. fasciata e Gracilaria birdiae e foram quantificados em tanques outdoor. As algas (50 g; n = 5) foram cultivadas em tanques de 50 L, com água eutrofizada, salinidade 30 e temperatura média 28,3 C. Os nutrientes foram monitorados diariamente e a biomassa foi mensurada assim que detectada a extinção do nitrogênio. Após cinco dias de cultivo, mais de 98% de NH3 (H = 1,1; P = 0,56) e de NO3- (H = 2,7; P = 0,25) e 62,1% de PO43- (H = 0,0; P = 0,9) foram removidos dos tanques. Contudo, a taxa de crescimento (% dia-1) e a produtividade (g m-2 dia-1) de U. fasciata e de G. birdiae (4,5 ± 2,5% dia-1; 3,5 ± 1,9 g m-2 dia-1) foram superiores às de U. flexuosa (13,6 ± 7,7% dia-1; 6,2 ± 2,8; P 0,01), cuja contaminação por microalgas contribuiu para elevada eficiência de retirada nos tanques desta espécie, mas baixo desempenho produtivo. Desta forma, U. fasciata e G. birdiae foram indicadas para AMTI tanto para a manutenção da qualidade da água quanto para aproveitamento de biomassa.(AU)

Transport of Astyanax altiparanae Garutti and Britski, 2000 in saline water / Transporte de Astyanax altiparanae Garutti and Britski, 2000 em água salinizada

Two experiments were performed. The first aimed to assess the tolerance of fingerlings Astyanax altiparanae to water salinity. Fish were exposed to salinity of 0, 3, 6, 9, 12 or 15 g NaCl L-1 for 96 hours. The fish mortality was 0%, in the levels of 0, 3 and 6 g L-1; 75% in the level of 9 g L-1and 100% at 12 and 15 g L-1 of common salt. The second experiment aimed to assess the parameters of water quality, mortality and blood glucose during transport. For this, A. altiparanae were stored in plastic bags at 22, 30 and 37 g of fish L-1 stocking densities and salinity of 0, 3, 6 and 9 g L-1, for. Fish showed similar mortality levels in the different salinities and stocking densities. The increase in fish density reduced the dissolved oxygen levels and salinity decreased the pH. The blood glucose levels were higher in those fish with 0 g L-1 salinity and higher stocking densities. The addition of salt to the water reduces the stress responses of A. altiparanae during transport.

Foram realizados dois experimentos. O primeiro teve o objetivo de avaliar a tolerância de alevinos de Astyanax altiparanae a salinidade da água. Os peixes foram submetidos às salinidades de 0, 3, 6, 9, 12 ou 15 g de NaCl L-1 durante 96 horas. A mortalidade dos peixes foi de 0%, nos níveis de 0, 3 e 6 g L-1; de 75% no nível de 9 g L-1 e de 100% em 12 e 15 g L- 1 de NaCl. No segundo experimento, objetivou-se avaliar os parâmetros de qualidade de água, mortalidade e a glicose sanguínea durante o transporte. Para isso, A. altiparanae foram estocados em sacos plásticos nas densidades de 22, 30 e 37 g de peixe L-1 e salinidades de 0, 3, 6 e 9 g de NaCl L-1. A mortalidade foi semelhante nas diferentes salinidades e densidades de estocagem. O aumento da densidade de peixes reduziu o nível de oxigênio dissolvido e a salinidade da água reduziu o pH. Os níveis de glicose sanguínea foram maiores nos peixes expostos a salinidade de 0 g L-1 e nas maiores densidades de estocagem. A adição de sal na água reduz as respostas de estresse em A. altiparanae durante o transporte.

Transport of Astyanax altiparanae Garutti and Britski, 2000 in saline water / Transporte de Astyanax altiparanae Garutti and Britski, 2000 em água salinizada

Two experiments were performed. The first aimed to assess the tolerance of fingerlings Astyanax altiparanae to water salinity. Fish were exposed to salinity of 0, 3, 6, 9, 12 or 15 g NaCl L-1 for 96 hours. The fish mortality was 0%, in the levels of 0, 3 and 6 g L-1; 75% in the level of 9 g L-1and 100% at 12 and 15 g L-1 of common salt. The second experiment aimed to assess the parameters of water quality, mortality and blood glucose during transport. For this, A. altiparanae were stored in plastic bags at 22, 30 and 37 g of fish L-1 stocking densities and salinity of 0, 3, 6 and 9 g L-1, for. Fish showed similar mortality levels in the different salinities and stocking densities. The increase in fish density reduced the dissolved oxygen levels and salinity decreased the pH. The blood glucose levels were higher in those fish with 0 g L-1 salinity and higher stocking densities. The addition of salt to the water reduces the stress responses of A. altiparanae during transport.(AU)

Foram realizados dois experimentos. O primeiro teve o objetivo de avaliar a tolerância de alevinos de Astyanax altiparanae a salinidade da água. Os peixes foram submetidos às salinidades de 0, 3, 6, 9, 12 ou 15 g de NaCl L-1 durante 96 horas. A mortalidade dos peixes foi de 0%, nos níveis de 0, 3 e 6 g L-1; de 75% no nível de 9 g L-1 e de 100% em 12 e 15 g L-1 de NaCl. No segundo experimento, objetivou-se avaliar os parâmetros de qualidade de água, mortalidade e a glicose sanguínea durante o transporte. Para isso, A. altiparanae foram estocados em sacos plásticos nas densidades de 22, 30 e 37 g de peixe L-1 e salinidades de 0, 3, 6 e 9 g de NaCl L-1. A mortalidade foi semelhante nas diferentes salinidades e densidades de estocagem. O aumento da densidade de peixes reduziu o nível de oxigênio dissolvido e a salinidade da água reduziu o pH. Os níveis de glicose sanguínea foram maiores nos peixes expostos a salinidade de 0 g L-1 e nas maiores densidades de estocagem. A adição de sal na água reduz as respostas de estresse em A. altiparanae durante o transporte.(AU)