The aim of this work was to evaluate different transport times for pacama juvenile (Lophiosilurus alexandri) previously trained to feed formulated diets. Four hundred and eighty-six pacama juveniles (2.52±0.71g) were submitted to 24 hours of fasting before transport. The animals were divided into nine plastic bags, with density of 54 juveniles in 5L of clean water for each bag after that inflated with pure oxygen and then sealed. Fish were transported for three hours and bags were open at 5, 6 and 7.5 hours after closing. For each time three replications were used. Survival was monitored for 96 hours post-transport. The longest time tested showed the lowest values of dissolved oxygen and pH, while the total ammonia was similar in the different treatments. Survival was 100% for different transport times after 96 hours. Some juveniles returned to feed 48 hours and the majority 72 hours after opening the bags, suggesting the efficiency of transport made at different times.

A maior parte dos estudos a respeito dos aspectos nutricionais do surubim está limitada às primeiras fases de desenvolvimento. Entretanto, é claro que o desempenho e a utilização dos nutrientes podem mudar durante os diferentes estágios de desenvolvimento destes animais. Assim sendo, este estudo teve como objetivo avaliar o desempenho e a utilização de nutrientes em juvenis de surubim alimentados com dietas contendo níveis variáveis de energia e proteína. Dois experimentos foram realizados para testar os diferentes níveis de proteína e energia. No primeiro experimento, juvenis de surubim (89,2±4,8g) foram alimentados com cinco dietas contendo níveis diferentes de energia (18.0, 18.8, 19.6, 20.5, 21.3MJ/kg). No segundo experimento, os juvenis (170,03±3,35g) foram alimentados com dietas contendo cinco níveis de proteína (360, 400, 440, 480 e 520g/kg). O melhor nível de energia para ganho de peso foi 20,3 MJ/kg. O aumento dos níveis de energia levou a um incremento nos níveis de lipídeo e diminuição da proteína corporal. Níveis de proteína entre 360 a 400g/kg foram os mais adequados para o desempenho e utilização dos nutrientes em juvenis grandes de surubim.

Most studies in nutrition for the South American catfish (surubim) were limited to the initial phase of development. However, it is clear that performance and nutrient utilization can change during the life stages of a fish. Therefore, this study aimed to evaluate the performance and nutrient utilization in juveniles of surubim fed diets varying in protein and energy levels. Two experiments were performed to test different levels of energy and protein in formulated diets. In the first experiment, surubim juveniles (89.2±4.8g) were fed five diets containing different levels of energy (18.0, 18.8, 19.6, 20.5, 21.3 MJ/kg). In the second experiment, juveniles (170.03±3.35g) were fed five diets containing different levels of protein (360, 400, 440, 480 and 520g/kg). The most favorable energy level for weight gain was 20.3 MJ/kg. The increasing energy levels provided a rise in fat and decrease in protein whole-body composition. The protein amount was between 360 to 400g/kg (383g/kg), which was adequate for performance and nutrient assimilation in surubim juveniles.

Avaliou-se o efeito da densidade de estocagem na produção de "cachadia" (Pseudoplatystoma fasciatum x Leiarius marmoratus) em sistema de recirculação de água. Nas duas primeiras fases, com duração de 27 e 40 dias e usando animais com média de peso inicial de 31 e 57g, respectivamente, foram testados 20, 40, 60 e 80 peixes/m³. Na terceira e quarta fase, usando peixes com média de peso de 169 e 399g durante 41 e 99 dias, respectivamente, foram testados 10, 20, 30 e 40 peixes/m³. A taxa de sobrevivência foi acima de 92%, sem diferenças significativas entre tratamentos. Verificou-se redução no ganho de peso diário com redução com o incremento da densidade na segunda e na quarta fase experimental. A biomassa final apresentou relação direta com a densidade em todas as fases. Taxas de conversão alimentar entre 0,8 e 1,3:1 foram registradas. O "cachadia" atingiu 1,1kg em 207 dias de cultivo, mostrando-se promissor para a piscicultura intensiva.

The aim of this study was to investigate the effect of different stocking densities on cachadia production (Pseudoplatystoma fasciatum x Leiarius marmoratus) in recirculating aquaculture system. In the two first phases for 27 and 40 days using fish with average weight of 31 and 57g, respectively, densities 20, 40, 60, and 80 fish/m³ were tested. In the third and fourth trial, using fish with an average weight of 169 and 399g during 41 and 99 days, respectively, densities 10, 20, 30, and 40 fish/m³ were tested. Survival rate was higher than 92%, without stocking density differences between the treatments. Daily weight gain showed reduction with the increase of the density in the second and fourth trial. However, final biomass presented direct relationship with increase density in all trials. Feed conversion rates ranged 0.8 from 1.3:1 were registered. Cachadia hybrid reached 1.1kg in approximately seven months of rearing indicating promise for intensive production.

Avaliaram-se os efeitos de diferentes fluxos de água e do condicionamento alimentar sobre a produção de juvenis de pacamã Lophiosilurus alexandri. Larvas com nove dias pós-eclosão (n=2.400) foram estocadas na densidade de 5 larvas/L. Diferentes fluxos (F) de água foram testados: F1 = 180; F2 = 600; F3 = 1.300; e F4 = 2.600mL/min. Náuplios de Artemia foram usados como alimento nos primeiros 15 dias de alimentação ativa. No segundo experimento, para o condicionamento alimentar, 720 juvenis (comprimento total de 22,2mm) foram estocados na densidade de 1,5 juvenis/L. Fluxo de água similar a F1 foi utilizado. Foram testados o uso de dieta extrusada e o condicionamento alimentar adicionado ou não de náuplios de Artemia ou emulsão Scott. Os diferentes fluxos de água não afetaram a sobrevivência e o crescimento de L. alexandri. Durante o condicionamento alimentar foi registrada a ocorrência de canibalismo. Pior sobrevivência, taxa de crescimento específica e maior mortalidade foram registradas para o uso da dieta comercial, enquanto valores similares foram verificados para as diferentes dietas usadas no condicionamento alimentar. Fluxo de água reduzido pode ser empregado durante a larvicultura e condicionamento alimentar de L. alexandri.

The effects of different water flow rates and feed training on the production of "pacamã" Lophiosilurus alexandri juveniles were evaluated. In the first experiment, nine day post-hatch larvae (n= 2,400) were stocked at a density of 5 larvae/L. Different water flow (F) rates were tested: F1 = 180; F2 = 600; F3 = 1,300; and F4 = 2,600mL/min. Artemia nauplii were offered as food during the first 15 days of active feeding. In the second experiment for feed training, 720 juveniles (total length of 22.2mm) were stocked at a density of 1.5 juveniles/L. A water flow rate similar to F1 was used. The use of extruded dry diet was tested, and feed training was done with and without other enhanced flavors (Artemia nauplii or Scott emulsion). The water flow rates did not influence the survival or growth of L. alexandri. Cannibalism occurred during feed training. The worst survival, specific growth rate and high mortality were found with the use of extruded dry diet, while similar values were registered with the different feed training diets used. Reduced water flow rate can be used to lower water consumption during larviculture and feed training of L. alexandri.