Macro, micromorphological and histological aspects of the intestine pirarucu Arapaima gigas (SCHINZ, 1822) (Osteoglossiformes: Arapaimidae) / Aspectos macro e micromorfológicos e histológicos do intestino do pirarucu Arapaima gigas (SCHINZ, 1822) (Osteoglossiformes: Arapaimidae)

Currently, the fish farming with Arapaima gigas has suffered from technological obstacles in the fields of reproduction, health and nutrition, making it necessary to know the morphology of its structures, so that it can advance in more technified research in scope of production in Rondônia state, as well as in aquaculture nutrition and health. Therefore, the aimed is to characterize the macro and microscopic morphology of posterior digestive system of A. gigas. The intestine of six specimens A. gigas in ideal slaughter size was analyzed. The analyzes were performed using light-sheet microscopy (LM) and scanning electron (SEM) techniques. The intestine basically showes similar histological characteristics in three analyzed portions (proximal, middle and distal). Same type of simple columnar epithelium with goblet cells was evidenced, with subtle variations in pattern of villi in each segment, and in number of goblet cells. In the rectum, the amount of goblet cells and evident longitudinal villi was expressive. Macroscopic anatomy and histology of the intestine A. gigas analyzed showes characteristics of adaptation to cultivation, according to their diet and habitat. The intestinal mucosa can divided into three distinct portions: proximal, middle and final intestine, in addition to the rectum and anus. In the pyloric cecum, the folds are slightly higher and poorly branched. The rectum, compared to the midgut, showed a higher occurrence of goblet cells in the mucosa. This increase in goblet cells observed in the posterior portion may related to the assimilation of ions and fluids that occur at this location.

Atualmente, a piscicultura do Arapaima gigas tem sofrido com entraves tecnológicos nos campos de reprodução, saúde e nutrição, fazendo-se necessário conhecer a morfologia de suas estruturas, para que se possa avançar em pesquisas mais tecnificadas no âmbito da produção piscícola no estado de Rondônia, bem como na nutrição e na sanidade aquícola. Por isso, objetiva-se caracterizar a morfologia macro e microscópica do sistema digestivo posterior do A. gigas. Foi analisado o intestino de seis espécimes de A. gigas em porte de abate. As análises foram realizadas por meio de técnicas de microscopia de luz (ML) e eletrônica de varredura (MEV). O intestino apresenta basicamente características histológicas similares nas três porções analisadas (proximal, médio e distal). Evidenciou-se um mesmo tipo de epitélio colunar simples com células caliciformes, variando o padrão de vilos em cada segmento de forma sutil, e o número de células caliciformes. No reto foi expressiva a quantidade de células caliciformes e as vilos longitudinais evidentes. A anatomia macroscópica e a histologia do intestino de A. gigas analisadas apresentam características de adaptação ao cultivo, conforme sua alimentação e habitat. A mucosa intestinal pode ser dividida em três porções distintas: intestino proximal, médio e final, além de reto e ânus. No ceco pilórico, as dobras são ligeiramente mais altas e pouco ramificadas. O reto, comparado ao intestino médio, apresentou maior ocorrência de células caliciformes na mucosa. Esse aumento de células caliciformes observado na porção posterior pode estar relacionado com a assimilação de íons e fluidos que ocorrem neste local.

Morphology of the digestive system in carnivorous freshwater dourado Salminus brasiliensis.

The digestive system of teleost shows remarkable functional and morphological diversity. In this study, the digestive tract and accessory organs of dourado Salminus brasiliensis are characterized using anatomical, histological, histochemical and immunohistochemical analyses. The existence of taste buds bordered by microridges in the oesophagus of dourado was recorded for the first time, thus showing that the species drives food intake by either swallowing or rejecting the food item. The Y-shaped stomach of dourado consisted of cardiac, cecal and pyloric regions with tubular gastric glands registered solely in the cardiac and cecal segments. The intestine is a short N-shaped tube with two loops, an intestinal coefficient of 0.73. The structure of pyloric caeca is similar to that of the intestine wall, comprising tunica mucosa, tela submucosa, tunica muscularis and tunica serosa layers. Histochemical analyses revealed an increased incidence of goblet cells from the midgut to the hindgut segment. A well-developed enteric plexus of scattered nerve cell and fibres are found along the digestive tract, and the calcitonin gene-related peptide (CGRP) immunoreactive neurons and fibres were identified in the myenteric plexus from the oesophagus to the hindgut. The exocrine pancreas appears diffuse in the mesentery around the stomach, intestine and also reaches the liver, and the endocrine pancreas is organized as a few islets of Langerhans. The liver comprises three distinct, asymmetric lobes, and the portal triad arrangement was registered in this tissue.

Effect of enzymatic complex in the diet of pirarucu, Arapaima gigas juveniles / Efeito de complexo enzimático na dieta para juvenis de pirarucu, Arapaima gigas

The pirarucu, Arapaima gigas is a native, carnivorous fish species from the Amazon basin. As carnivorous fish have low amylase activity, exogenous enzymes can improve the digestibility of carbohydrates in aquaculture feeds. We evaluated the digestibility of increasing levels of an enzymatic complex in diets of pirarucu juveniles (65.2 ± 0.4 g). The experimental design was randomized with four treatments [diets containing 0.25, 0.50, 0.75, and 1 g kg-1 on-top inclusion of an enzyme complex (Allzyme® SSF®, USA), and a control, with three replications at a density of 5 fish per unit, and a 30-day duration. We quantified apparent digestibility of dry matter, crude protein, and crude energy through nutrient and chromium oxide content in diets and feces. Enzymatic activity, hepatic glycogen and total protein were determined in liver and anterior intestine samples. The diet with 1 g kg-1 of enzyme-complex resulted in an increase in apparent digestibility of crude protein, gross energy, and dry matter, hepatic glycogen, total proteins in liver and in intestine, showing the efficiency of the enzyme complex in pirarucu feeding. A higher accumulation of dry matter, crude energy, and ethereal extract in the carcass indicated weight increase in the fish treated with enzymatic complex. A decrease in the endogenous enzymatic activity (protease, lipase and amylase) suggested an improved efficacy of the digestive process. Our results indicate that the inclusion of 1 g kg-1 enzyme complex in the diet of juvenile pirarucu can be recommended to achieve greater digestibility of nutrients and improvement in productive performance.(AU)

O pirarucu, Arapaima gigas é um peixe carnívoro nativo da bacia amazônica. Como peixes carnívoros possuem baixa atividade de amilase, enzimas exógenas melhoram a digestibilidade de carboidratos em rações para aquacultura. O objetivo deste estudo foi avaliar a digestibilidade de níveis crescentes de complexo enzimático em dietas para juvenis de pirarucu (65,2 ± 0,4 g). O desenho experimental foi randomizado com quatro tratamentos [dietas contendo 0,25, 0,50, 0,75 e 1 g kg-1 de complexo enzimático adicionado (Allzyme® SSF®, EUA)] e um controle, com três réplicas com densidade de cinco peixes por unidade e 30 dias de duração. A digestibilidade aparente da matéria seca, proteína bruta e energia bruta foi calculada por quantificação de nutrientes e óxido de cromo nas dietas e fezes. A atividade enzimática, o glicogênio hepático e a proteína total foram determinados a partir de amostras do fígado e intestino anterior. A dieta com 1 g kg-1 de complexo enzimático resultou em um aumento da digestibilidade aparente de proteina bruta, energia bruta, matéria seca, glicogênio hepático e proteínas totais no fígado e intestino, mostrando a eficácia do complexo enzimático na dieta dos pirarucus. A acumulação mais alta de matéria seca, energia bruta e extrato etéreo na carcaça indicou o aumento de peso dos peixes tratados com complexo enzimático. A redução da atividade enzimática endógena (protease, lipase e amilase) sugeriu um aumento da eficácia do processo digestivo. Nossos resultados indicam que a inclusão de 1 g kg-1 do complexo enzimático na dietas de juvenis de pirarucu pode ser recomendada para obter maior digestibilidade de nutientes e performance produtiva.(AU)

Live and frozen Artemia nauplii for catfish Lophiosilurus alexandri (Steindachner, 1876) larvae in different salinities.

The objective of the study was to verify the combination of live and frozen Artemia nauplii, in different salinized water, and its influence in growth and survival of the catfish Lophiosilurus alexandri (Steindachner, 1876) larvae. Larvae were exposed to a combination of two feeds and two different salinities: live Artemia nauplii + 0‰ salinity in the water; live Artemia nauplii + 2‰ salinity in the water; frozen Artemia nauplii + 0‰ salinity in the water; and frozen Artemia nauplii + 2‰ salinity in the water. The experiment was conducted in a randomized design, in a 2 × 2 factorial scheme, 5 replicates, during 15 days. The larvae final weight, weight gain, food conversion, standard and total length, biomass, survival, body width, intestinal quotient, Fulton's condition factor, and water quality were evaluated. The use of Artemia nauplii and 2 ppm salinized water for L. alexandri larviculture proved to be adequate providing greater growth. This was due to Artemia nauplii being kept alive and attractive for the cultivation of larvae in salinized water, even though salt was a stress factor. Already, the frozen Artemia nauplii was a viable food but should be used preferably in times of lack of live nauplii and without salinization of the water.

Soybean meal in diets for juveniles of pirarucu / Farelo de soja na dieta de juvenis de pirarucu

In order to assess the effects of replacing fishmeal (FM) protein by soybean meal (SM) for juveniles of pirarucu (Arapaima gigas) feeds, five isonitrogenous (46% CP) and isocaloric (4,800 kcal kg-1 GE) diets containing 0, 15, 30, 45 and 60% replacement were tested. One hundred and five fish (233.5 ± 11.5 g) were distributed in fifteen 200-L tanks, fed three times daily to apparent satiation for 120 days. The highest growth rates were observed in diets with up to 30% replacement, but no significant difference was detected as regards to specific growth rate, feed conversion ratio, mean daily feed intake and mean daily protein intake in fish fed diets with up to 45% FM replacement. Survival rate, condition factor, hepatosomatic and viscerosomatic indexes were not influenced by the treatments, just as the biochemical analyses were not, except for cholesterol. Fish fed diets with increasing levels of SM presented lower hematological values, and higher mean corpuscular value, indicating probable anemia at 60% FM replacement and hypocholesterolemia. Diets with 15 and 30% FM replacement were the most cost effective suggesting that SM can replace up to 30% of FM in diets for pirarucu juveniles (200 to 1,200 g), without compromising growth performance, fish health, feed digestibility and feed cost effectiveness.

Para avaliar os efeitos da proteína do farelo de soja (FS), substituindo a proteína da farinha de peixe (FP) na alimentação de juvenis de pirarucu, foram testadas cinco dietas isoproteicas (46% PB) e isocalóricas (4800 kcal kg-1 EB), contendo 0, 15, 30, 45 e 60% de substituição. Cento e cinco exemplares (233,5 ± 11,5 g) foram distribuídos em 15 tanques (200 L), alimentados três vezes ao dia, até saciedade aparente, por 120 dias. Os maiores ganho de peso foram obtidos até 30% de substituição, sem diferenças significativas para taxa de crescimento específico, conversão alimentar aparente, consumo médio diário de ração e consumo médio diário de proteína com até 45% de FS. Não houve diferenças estatísticas para sobrevivência, fator de condição, índice hepatossomático e víscerossomático e nas análises bioquímicas, exceto colesterol. Os valores hematológicos diminuíram com os níveis de substituição, com elevação do volume corpuscular médio, indicando provável quadro de anemia em 60% de FS e de hipocolesterolemia. Dietas com 15 e 30% de FS foram mais viáveis, sugerindo a substituição até 30% da FP pelo FS (inclusão de 22%) em dietas para pirarucu (200 a 1.200 g), sem prejuízos aos parâmetros zootécnicos, saúde dos peixes e menor custo de produção.

Soybean meal in diets for juveniles of pirarucu / Farelo de soja na dieta de juvenis de pirarucu

In order to assess the effects of replacing fishmeal (FM) protein by soybean meal (SM) for juveniles of pirarucu (Arapaima gigas) feeds, five isonitrogenous (46% CP) and isocaloric (4,800 kcal kg-1 GE) diets containing 0, 15, 30, 45 and 60% replacement were tested. One hundred and five fish (233.5 ± 11.5 g) were distributed in fifteen 200-L tanks, fed three times daily to apparent satiation for 120 days. The highest growth rates were observed in diets with up to 30% replacement, but no significant difference was detected as regards to specific growth rate, feed conversion ratio, mean daily feed intake and mean daily protein intake in fish fed diets with up to 45% FM replacement. Survival rate, condition factor, hepatosomatic and viscerosomatic indexes were not influenced by the treatments, just as the biochemical analyses were not, except for cholesterol. Fish fed diets with increasing levels of SM presented lower hematological values, and higher mean corpuscular value, indicating probable anemia at 60% FM replacement and hypocholesterolemia. Diets with 15 and 30% FM replacement were the most cost effective suggesting that SM can replace up to 30% of FM in diets for pirarucu juveniles (200 to 1,200 g), without compromising growth performance, fish health, feed digestibility and feed cost effectiveness.(AU)

Para avaliar os efeitos da proteína do farelo de soja (FS), substituindo a proteína da farinha de peixe (FP) na alimentação de juvenis de pirarucu, foram testadas cinco dietas isoproteicas (46% PB) e isocalóricas (4800 kcal kg-1 EB), contendo 0, 15, 30, 45 e 60% de substituição. Cento e cinco exemplares (233,5 ± 11,5 g) foram distribuídos em 15 tanques (200 L), alimentados três vezes ao dia, até saciedade aparente, por 120 dias. Os maiores ganho de peso foram obtidos até 30% de substituição, sem diferenças significativas para taxa de crescimento específico, conversão alimentar aparente, consumo médio diário de ração e consumo médio diário de proteína com até 45% de FS. Não houve diferenças estatísticas para sobrevivência, fator de condição, índice hepatossomático e víscerossomático e nas análises bioquímicas, exceto colesterol. Os valores hematológicos diminuíram com os níveis de substituição, com elevação do volume corpuscular médio, indicando provável quadro de anemia em 60% de FS e de hipocolesterolemia. Dietas com 15 e 30% de FS foram mais viáveis, sugerindo a substituição até 30% da FP pelo FS (inclusão de 22%) em dietas para pirarucu (200 a 1.200 g), sem prejuízos aos parâmetros zootécnicos, saúde dos peixes e menor custo de produção.(AU)

Fish protein hydrolysate as an ingredient in diets for Arapaima gigas juveniles / Hidrolisado protéico de peixe em dietas para juvenis de Arapaima gigas

This study evaluated the dietary inclusion of a fish protein hydrolysate (FPH) derived from from tilapia trimmings, on physiological and growth parameters of juveniles of Arapaima gigas. A total of 180 arapaima juveniles (91.4 ± 2.7 g) were used in a complete randomized design with six treatments (n = 3). Fish were fed to apparent satiation four times a day for eight weeks, with diets containing increasing inclusion levels of FPH (0, 4, 8, 12, 16 and 20%). FPH diets did not affect growth and hemato-biochemical parameters of arapaima juveniles. The FPH from tilapia trimmings seems to be a suitable ingredient for arapaima over 90 g feeds, at least up to 20% inclusion level. No bioactive effects of the FPH could be detected.(AU)

Este estudo avaliou a inclusão na dieta de um hidrolisado de proteína de peixe (FPH) derivado de aparas de tilápia sobre parâmetros fisiológicos, crescimento e composição proximal do músculo de juvenis de Arapaima gigas. Cento e oitenta juvenis de arapaima (91,4 ± 2,7 g) foram utilizados em delineamento inteiramente casualizado, com seis tratamentos (n = 3). Os peixes foram alimentados até saciedade aparente quatro vezes por dia durante oito semanas, com dietas contendo níveis crescentes de inclusão de FPH (0, 4, 8, 12, 16 e 20%). As dietas de FPH não afetaram o crescimento e os parâmetros hemato-bioquímicos de juvenis de arapaima. O FPH de aparas de tilápia parece ser um ingrediente adequado para rações de arapaima acima de 90 g, pelo menos até 20% de inclusão. Nenhum efeito bioativo da FPH pode ser detectado.(AU)

Fish protein hydrolysate as an ingredient in diets for Arapaima gigas juveniles / Hidrolisado protéico de peixe em dietas para juvenis de Arapaima gigas

This study evaluated the dietary inclusion of a fish protein hydrolysate (FPH) derived from from tilapia trimmings, on physiological and growth parameters of juveniles of Arapaima gigas. A total of 180 arapaima juveniles (91.4 ± 2.7 g) were used in a complete randomized design with six treatments (n = 3). Fish were fed to apparent satiation four times a day for eight weeks, with diets containing increasing inclusion levels of FPH (0, 4, 8, 12, 16 and 20%). FPH diets did not affect growth and hemato-biochemical parameters of arapaima juveniles. The FPH from tilapia trimmings seems to be a suitable ingredient for arapaima over 90 g feeds, at least up to 20% inclusion level. No bioactive effects of the FPH could be detected.

Este estudo avaliou a inclusão na dieta de um hidrolisado de proteína de peixe (FPH) derivado de aparas de tilápia sobre parâmetros fisiológicos, crescimento e composição proximal do músculo de juvenis de Arapaima gigas. Cento e oitenta juvenis de arapaima (91,4 ± 2,7 g) foram utilizados em delineamento inteiramente casualizado, com seis tratamentos (n = 3). Os peixes foram alimentados até saciedade aparente quatro vezes por dia durante oito semanas, com dietas contendo níveis crescentes de inclusão de FPH (0, 4, 8, 12, 16 e 20%). As dietas de FPH não afetaram o crescimento e os parâmetros hemato-bioquímicos de juvenis de arapaima. O FPH de aparas de tilápia parece ser um ingrediente adequado para rações de arapaima acima de 90 g, pelo menos até 20% de inclusão. Nenhum efeito bioativo da FPH pode ser detectado.

Larviculture of a carnivorous freshwater catfish, Lophiosilurus alexandri, screened by personality type.

Considering that each personality type in animals presents distinct physiological and behavioural responses, this study evaluated the efficiency of the Novel Environment test to classify larvae of Lophiosilurus alexandri into bold and shy individuals, which were then investigated for growth, cannibalism and mortality in larviculture of pure and mixed groups. Larvae with an average weight of 24.0±1.7mg and length of 14.1±0.4mm, were subjected to a Novel Environment test to classify their personality type (bold and shy larvae). After the larvae were classified according to personality type, they were subjected to larviculture for 15days. Three treatments were tested: only bold larvae, only shy larvae, and a mixed treatment (bold larvae+shy larvae) at a density for 16 larvae/L, which were fed 3 times a day with Artemia nauplii. After larviculture, there were no differences in the final lengths of larvae of the bold, shy, and mixed treatments (26.9±0.76mm, 26.7±1.00mm, and 26.8±1.24mm, respectively); however, shy larvae possessed weighed less (0.22±0.01g) than the bold and mixed treatments, which did not differ significantly (0.25±0.02g and 0.27±0.02g, respectively). The bold and mixed treatments had the highest cannibalism rate (11.2±5.1% and 23.1±12.3%, respectively). Overall survival was lowest in the mixed treatment (62.5±13.0%), while that of the bold and shy treatments were similar (82.5±9.2% and 86.2±9.2%, respectively). The separation of L. alexandri larvae by traits can ensure a decrease in cannibalism and hence, more productive larviculture.

Early sexing techniques in Lophiosilurus alexandri (Steindachner, 1876), a freshwater carnivorous catfish.

This study aimed to evaluate sexing techniques for juvenile Lophiosilurus alexandri. With this aim, we evaluated three techniques: coelioscopy, performed with the use of video surgery equipment; coeliotomy, a surgical procedure for direct visualization of the gonads; and sex determination using a urethral probe to compare the genital papillae. For coelioscopy, the survival rate was 100% 30 days after the procedure, and the fish restarted eating 10 days after surgery. This technique resulted in a 100% correct identification of individuals identified as females, whereas for males, it was 66.6%. There was no significant difference between males and females for anesthesia induction and recovery times. However, the procedure took longer for males because of the difficulty in observing the gonads, which can be attributed to the large amount of visceral fat in males. Coeliotomy also resulted in a 100% survival rate 30 days after surgery, and the efficiency of this technique was 96.3% for males and 93.9% for females. The fish restarted eating between 10 and 14 days after surgery, and there were no significant differences between males and females for anesthesia induction and recovery times for the surgical procedure to visualize the gonads (P > 0.05). The urethral probe technique was less efficient with an accuracy rate of 67.8% and 81.8% for males and females, respectively. We conclude that coeliotomy was more efficient for sexing both sexes of juvenile L. alexandri.

Desempenho produtivo e econômica de surubins (pseudoplatystoma sp) alimentados com níveis de proteína e estocados em tanque-rede / Growth performance and economic of pseudoplatystoma sp fed with protein levels reared in net cages

O surubim (Pseudoplatystoma sp.) é uma das espécie de peixe mais apreciadas para o consumo. Por ser uma espécie carnívora, exige atenção especial no que tange às suas exigências nutricionais. Até o momento, poucos estudos foram realizados para estabelecê-las na fase de engorda, em especial em sistema de cultivo intensivo. O objetivo do presente estudo foi avaliar os desempenhos zootécnico e econômico de surubins (Pseudoplatystoma sp.) na fase final de crescimento, estocados em tanque-rede e alimentados com dietas com diferentes níveis de proteína. Os peixes, com peso de 356,6±40,3g, foram acondicionados em 12 tanques-rede de 18m3, nos quais permaneceram por cinco meses até adquirirem o peso comercial para abate. O tratamento experimental foi constituído por três dietas extrusadas comerciais, com os níveis de proteína bruta (36, 38, 40%PB) sendo substituídos gradativamente por carboidratos. Foram avaliados os parâmetros de crescimento, rendimento de filé, enzimas metabólicas e desempenho econômico. O ganho de peso, o ganho de peso diário, o consumo de dieta, a taxa de eficiência proteica, a sobrevivência e o rendimento de filé não apresentaram diferença significativa. A conversão alimentar foi melhor para os peixes alimentados com a dieta com 38 e 40%PB. Não foram observadas diferenças significativas para os parâmetros de índice hepatossomático e de enzimas hepáticas. Apesar dos maiores gastos com a ração contendo 38%PB em comparação à dieta com 36%PB, esta foi a que apresentou o melhor índice de custo por kg de peixe produzido. Os melhores índices de crescimento e o menor custo de arraçoamento foram obtidos pelos peixes alimentados com a dieta 38%PB, sendo esta, portanto recomendada para o arraçoamento na fase final de surubins em tanque-rede.

The Pseudoplatystoma sp. is one of the most appreciated fish species for consumption. Being a carnivorous species, the painted requires special attention regarding their nutritional requirements. To date, few studies have been conducted to establish them in their stage of fattening especially in intensive cultivation systems. The aim of the present study was to evaluate the growth and economic performance of Pseudoplatystoma sp fed with protein levels reared in net cages. The fish weighing from 356.6 ± 40.3g were packed in twelve net cages in 18 m3 in which they remained for five months until acquiring the commercial weight for slaughter. The experimental treatment was constituted by three commercial extruded diets with different crude protein levels (36, 38, 40% CP) gradually being replaced with carbohydrate. Growth parameters, metabolic enzymes, fillet yield and economic performance were evaluated. The gain in weight, daily weight gain, diet consumption, protein efficiency rate, survival and fillet yield did not show significant difference. The feed conversion was best for fish fed a diet with 38 and 40% CP. No significant differences were observed for the hepatossomatic index parameters and liver enzymes. There were larger expenditures on rations containing 38% PB compared to the diet with 36% CP, this presented the best index of cost per kg of fish produced. The best growth rates and lower cost of feeding were obtained by fish fed with a 38% CP diet, which is, therefore, recommended for feeding in the final phase of surubins monitored via net cages.

Desempenho produtivo e econômica de surubins (Pseudoplatystoma sp) alimentados com níveis de proteína e estocados em tanque-rede / Growth performance and economic of Pseudoplatystoma sp fed with protein levels reared in net cages

O surubim (Pseudoplatystoma sp.) é uma das espécie de peixe mais apreciadas para o consumo. Por ser uma espécie carnívora, exige atenção especial no que tange às suas exigências nutricionais. Até o momento, poucos estudos foram realizados para estabelecê-las na fase de engorda, em especial em sistema de cultivo intensivo. O objetivo do presente estudo foi avaliar os desempenhos zootécnico e econômico de surubins (Pseudoplatystoma sp.) na fase final de crescimento, estocados em tanque-rede e alimentados com dietas com diferentes níveis de proteína. Os peixes, com peso de 356,6±40,3g, foram acondicionados em 12 tanques-rede de 18m3, nos quais permaneceram por cinco meses até adquirirem o peso comercial para abate. O tratamento experimental foi constituído por três dietas extrusadas comerciais, com os níveis de proteína bruta (36, 38, 40%PB) sendo substituídos gradativamente por carboidratos. Foram avaliados os parâmetros de crescimento, rendimento de filé, enzimas metabólicas e desempenho econômico. O ganho de peso, o ganho de peso diário, o consumo de dieta, a taxa de eficiência proteica, a sobrevivência e o rendimento de filé não apresentaram diferença significativa. A conversão alimentar foi melhor para os peixes alimentados com a dieta com 38 e 40%PB. Não foram observadas diferenças significativas para os parâmetros de índice hepatossomático e de enzimas hepáticas. Apesar dos maiores gastos com a ração contendo 38%PB em comparação à dieta com 36%PB, esta foi a que apresentou o melhor índice de custo por kg de peixe produzido. Os melhores índices de crescimento e o menor custo de arraçoamento foram obtidos pelos peixes alimentados com a dieta 38%PB, sendo esta, portanto recomendada para o arraçoamento na fase final de surubins em tanque-rede.(AU)

The Pseudoplatystoma sp. is one of the most appreciated fish species for consumption. Being a carnivorous species, the painted requires special attention regarding their nutritional requirements. To date, few studies have been conducted to establish them in their stage of fattening especially in intensive cultivation systems. The aim of the present study was to evaluate the growth and economic performance of Pseudoplatystoma sp fed with protein levels reared in net cages. The fish weighing from 356.6 ± 40.3g were packed in twelve net cages in 18 m3 in which they remained for five months until acquiring the commercial weight for slaughter. The experimental treatment was constituted by three commercial extruded diets with different crude protein levels (36, 38, 40% CP) gradually being replaced with carbohydrate. Growth parameters, metabolic enzymes, fillet yield and economic performance were evaluated. The gain in weight, daily weight gain, diet consumption, protein efficiency rate, survival and fillet yield did not show significant difference. The feed conversion was best for fish fed a diet with 38 and 40% CP. No significant differences were observed for the hepatossomatic index parameters and liver enzymes. There were larger expenditures on rations containing 38% PB compared to the diet with 36% CP, this presented the best index of cost per kg of fish produced. The best growth rates and lower cost of feeding were obtained by fish fed with a 38% CP diet, which is, therefore, recommended for feeding in the final phase of surubins monitored via net cages.(AU)

Rendimento de carcaça de surubins Pseudoplatystoma spp. produzidos em viveiros sob diferentes densidades de estocagem / Carcass yield of surubins Pseudoplatystoma spp. reared in ponds under different stocking densities

Avaliou-se o rendimento de carcaça de surubins Pseudoplatystoma spp. produzidos em viveiros sob diferentes densidades de estocagem. Adotou-se o delineamento inteiramente casualizado, com três tratamentos (densidades) e nove repetições. As densidades foram: densidade 1: (1peixe/5m2), densidade 2 (1 peixe/ 3m2) e densidade 3 (1 peixe/2,14m2). Surubins com peso total médio de 1,144 ± 0,340 kg, foram sacrificados por choque térmico em gelo para determinação dos rendimentos do peixe eviscerado com e sem cabeça (RPECC; RPESC), do filé lateral com e sem pele (RFLCP; PFLSP), do filé abdominal com e sem pele (RFACP; RFASP), da cabeça (RC), de pele (RP), de vísceras (RV), de resíduos (RR). Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5%. Para estimação do comportamento dos rendimentos e percentuais de participação dos componentes da carcaça em função do peso final dos peixes, foram estimadas equações de regressão. Não foi verificada diferença (P>0,05) dos tratamentos sobre as variáveis de rendimento. Valores médios para RPECC, RC, RFLSP, RFASP, RP, RV e RR foram de 91,44 ± 2,20%; 21,17 ± 1,57%; 30,01 ± 2,48%; 12,74 ± 1,17%; 6,71 ± 1,21%; 7,61 ± 2,23%; 20,11 ± 3,01%, respectivamente. As correlações do peso do peixe com os rendimentos foram fracas, indicando que o peso final não é um indicador confiável de rendimento de cortes. As análises de componentes principais (CP) indicaram que quatro destes foram suficientes para explicar mais de 90% da variação total, resultante da combinação da variável peso final e os rendimentos. A avaliação do comportamento dos rendimentos e percentuais de participaçãono peso total dos peixes dos diferentes componentes de carcaça em função do peso final dos animais indicou comportamento linear para (RPECC, RC e RV). Os rendimentos de processamento de surubins independem da densidade de estocagem e apresentam valores semelhantes.(AU)

The aim of this study was to evaluate carcass yield of surubins Pseudoplatystoma spp. reared in ponds under different stocking densities. We performed a completely randomized design, with three treatments(density) and nine repetitions. The densities were: density 1 (1peixe/5m2), density 2 (1 fish/3m2) and 3 density (1 fish/2.14 m2). Surubins total average weight of 1.144 ± 0.340 kg, were slaughtered by thermal shock in ice for determining yields of eviscerated fish with and no head (YEFWH; YEFWNH), the lateral fillet with and with no skin (YLFWS; YLFWNS) of abdominal fillet with and with no skin (YAFWS; YAFWNS), head (YH), skin (YS), viscera (YV) of residues (YR). Data were subjected to analysis of variance and average was compared by Tukey test at 5%. In order to steeming the relation amongincome on percentage of carcass components depending on the final weight of the fish we reckoned regression equations. There was no difference (P>0.05) of treatment through the variables of income. Average values for YEFWH, YH, YLFWNS, YAFWNS, YS, YV and YR were 91.44 ± 2.20%, 21.17 ± 1.57%, 30.01 ± 2.48%, 12.74 ± 1, 17%, 6.71 ± 1.21%, 7.61% ± 2.23, 20.11 ± 3.01%, respectively. The correlations of weight of fish yields were trivial, thus, they showed that the final weight is not a reliable indicator of yield cuts. The principal component analysis (PC) indicated that four of those tests were sufficient to explain 90% of the total variation, resulting from the combination of the variables final weight and yields. The performance evaluation of income on percentage of participation in the fish total weight of the different components of carcass depending on the final weight of the animals showed linear manner for (YEFWH, YH and YV). Surubim yields processing does not depend on stocking density and they have similar values.(AU)

Levels of digestible protein to surubim (Pseudoplatystoma sp) reared in net cages / Níveis de proteína digestível para surubim (Pseudoplatystoma sp) criados em tanque-rede

The Pseudoplatystoma sp. is species of carnivorous fish that require special attention in the diet offered. This work had the objective to determine the digestible protein requirement of juvenile the Pseudoplatystoma sp. reared in net cages. The test consisted of four isoenergetic diets (2606.69 ± 39.16 kcal kg-1 of digestible energy) containing increasing levels of digestible protein (23, 24, 26 and 28%PD) provided to juveniles of surubim (157.35±11.23g) for five months. The parameters of growth, fillet composition, metabolic liver enzymes and morphometry of the intestine and liver were analyzed in completely randomized design with four treatments and four replicates. An increase of protein in the diet provided better weight gain. The metabolic liver enzymes increased in fish fed 24PD. The histopathological changes were not observed in the liver of the fish. The bowel histology showed adaptation to increased protein in the diet until the 26 level PD. juveniles of Pseudoplatystoma sp. Were demanding in digestible protein, showing the best results of production performance and nutrient use efficiency with the diet containing 28%PD.(AU)

O surubim (Pseudoplatystoma sp.) é uma das espécie de peixe carnívora que exige atenção especial na dieta ofertada. Este trabalho teve o objetivo determinar a exigência de proteína digestível de juvenis de surubim (Pseudoplatystoma sp.) criados em tanque-rede. O ensaio foi constituído por quatro dietas isoenergéticas (2606,69±39,16 kcal. kg-1 de energia digestível) contendo níveis crescentes de proteína digestível (23, 24, 26 e 28 % PD) fornecidas aos juvenis de surubim (157,35± 11,23g) durante cinco meses. Os parâmetros de crescimentos, composição do filé, enzimas metabólicas hepáticas e morfometria do intestino e fígado foram analisados em delineamento inteiramente casualizado com quatro tratamentos e quatro repetições. O aumento de proteína na dieta proporcionou melhor ganho em peso. As enzimas do metabolismo hepático aumentaram nos peixes alimentados com 24%PD. Não foram observadas alterações histopatológicas no fígado dos peixes. A histologia do intestino revelou adaptação ao aumento de proteína na dieta até o nível de 26% PD. Os juvenis de surubim mostraram-se exigentes em proteína digestível, apresentando os melhores resultados de desempenho de produção e de eficiência de utilização dos nutrientes com a dieta contendo 28% de PD.(AU)

Effect of fishmeal replacement by soy protein concentrate with taurine supplementation on hepatic intermediary metabolism and antioxidant status of totoaba juveniles (Totoaba macdonaldi).

The effect of dietary incorporation of soy protein concentrate (SPC) and the concomitant supplementation with taurine on hepatic intermediary metabolism and antioxidant status of totoaba (Totoaba macdonaldi) juveniles was assessed. Four isoproteic and isolipidic diets were formulated containing either 30 or 60% of SPC (diets SP30 and SP60), supplemented or not with 1% of taurine (diets SP30T and SP60T). A fish meal (FM) based diet, without SPC and taurine supplementation, was used as a control. Triplicate groups of 32 totoaba juveniles (average body mass=7.5g) were fed these diets over 45days. Results revealed that dietary FM replacement by SPC depressed the overall intermediary metabolism. Activity of key enzymes of amino acid catabolism and gluconeogenesis was significantly reduced and a trend to reduce glycolysis and glucose-6-phosphate dehydrogenase activity was observed. The incorporation of the highest level of SPC also significantly increased hepatic lipid peroxidation and the activity of superoxide dismutase. Concomitant taurine supplementation restored the activity of amino acid catabolic and gluconeogenic enzymes and hexokinase to levels similar of those of the control diet. Taurine supplementation also led to a significant increase of glucose-6-phosphate dehydrogenase and catalase activity, as well as to a significant reduction of liver lipid peroxidation. These results suggest that taurine may play an important metabolic modulation action on totoaba fed SPC based diets, contributing to the enhancement of the overall metabolism and to the reduction of liver oxidative damage.

Rendimento de carcaça de surubins Pseudoplatystoma spp. produzidos em viveiros sob diferentes densidades de estocagem / Carcass yield of surubins Pseudoplatystoma spp. reared in ponds under different stocking densities

Avaliou-se o rendimento de carcaça de surubins Pseudoplatystoma spp. produzidos em viveiros sob diferentes densidades de estocagem. Adotou-se o delineamento inteiramente casualizado, com três tratamentos (densidades) e nove repetições. As densidades foram: densidade 1: (1peixe/5m2), densidade 2 (1 peixe/ 3m2) e densidade 3 (1 peixe/2,14m2). Surubins com peso total médio de 1,144 ± 0,340 kg, foram sacrificados por choque térmico em gelo para determinação dos rendimentos do peixe eviscerado com e sem cabeça (RPECC; RPESC), do filé lateral com e sem pele (RFLCP; PFLSP), do filé abdominal com e sem pele (RFACP; RFASP), da cabeça (RC), de pele (RP), de vísceras (RV), de resíduos (RR). Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5%. Para estimação do comportamento dos rendimentos e percentuais de participação dos componentes da carcaça em função do peso final dos peixes, foram estimadas equações de regressão. Não foi verificada diferença (P>0,05) dos tratamentos sobre as variáveis de rendimento. Valores médios para RPECC, RC, RFLSP, RFASP, RP, RV e RR foram de 91,44 ± 2,20%; 21,17 ± 1,57%; 30,01 ± 2,48%; 12,74 ± 1,17%; 6,71 ± 1,21%; 7,61 ± 2,23%; 20,11 ± 3,01%, respectivamente. As correlações do peso do peixe com os rendimentos foram fracas, indicando que o peso final não é um indicador confiável de rendimento de cortes. As análises de componentes principais (CP) indicaram que quatro destes foram suficientes para explicar mais de 90% da variação total, resultante da combinação da variável peso final e os rendimentos. A avaliação do comportamento dos rendimentos e percentuais de participaçãono peso total dos peixes dos diferentes componentes de carcaça em função do peso final dos animais indicou comportamento linear para (RPECC, RC e RV). Os rendimentos de processamento de surubins independem da densidade de estocagem e apresentam valores semelhantes.

The aim of this study was to evaluate carcass yield of surubins Pseudoplatystoma spp. reared in ponds under different stocking densities. We performed a completely randomized design, with three treatments(density) and nine repetitions. The densities were: density 1 (1peixe/5m2), density 2 (1 fish/3m2) and 3 density (1 fish/2.14 m2). Surubins total average weight of 1.144 ± 0.340 kg, were slaughtered by thermal shock in ice for determining yields of eviscerated fish with and no head (YEFWH; YEFWNH), the lateral fillet with and with no skin (YLFWS; YLFWNS) of abdominal fillet with and with no skin (YAFWS; YAFWNS), head (YH), skin (YS), viscera (YV) of residues (YR). Data were subjected to analysis of variance and average was compared by Tukey test at 5%. In order to steeming the relation amongincome on percentage of carcass components depending on the final weight of the fish we reckoned regression equations. There was no difference (P>0.05) of treatment through the variables of income. Average values for YEFWH, YH, YLFWNS, YAFWNS, YS, YV and YR were 91.44 ± 2.20%, 21.17 ± 1.57%, 30.01 ± 2.48%, 12.74 ± 1, 17%, 6.71 ± 1.21%, 7.61% ± 2.23, 20.11 ± 3.01%, respectively. The correlations of weight of fish yields were trivial, thus, they showed that the final weight is not a reliable indicator of yield cuts. The principal component analysis (PC) indicated that four of those tests were sufficient to explain 90% of the total variation, resulting from the combination of the variables final weight and yields. The performance evaluation of income on percentage of participation in the fish total weight of the different components of carcass depending on the final weight of the animals showed linear manner for (YEFWH, YH and YV). Surubim yields processing does not depend on stocking density and they have similar values.

Levels of digestible protein to surubim (Pseudoplatystoma sp) reared in net cages / Níveis de proteína digestível para surubim (Pseudoplatystoma sp) criados em tanque-rede

The Pseudoplatystoma sp. is species of carnivorous fish that require special attention in the diet offered. This work had the objective to determine the digestible protein requirement of juvenile the Pseudoplatystoma sp. reared in net cages. The test consisted of four isoenergetic diets (2606.69 ± 39.16 kcal kg-1 of digestible energy) containing increasing levels of digestible protein (23, 24, 26 and 28%PD) provided to juveniles of surubim (157.35±11.23g) for five months. The parameters of growth, fillet composition, metabolic liver enzymes and morphometry of the intestine and liver were analyzed in completely randomized design with four treatments and four replicates. An increase of protein in the diet provided better weight gain. The metabolic liver enzymes increased in fish fed 24PD. The histopathological changes were not observed in the liver of the fish. The bowel histology showed adaptation to increased protein in the diet until the 26 level PD. juveniles of Pseudoplatystoma sp. Were demanding in digestible protein, showing the best results of production performance and nutrient use efficiency with the diet containing 28%PD.

O surubim (Pseudoplatystoma sp.) é uma das espécie de peixe carnívora que exige atenção especial na dieta ofertada. Este trabalho teve o objetivo determinar a exigência de proteína digestível de juvenis de surubim (Pseudoplatystoma sp.) criados em tanque-rede. O ensaio foi constituído por quatro dietas isoenergéticas (2606,69±39,16 kcal. kg-1 de energia digestível) contendo níveis crescentes de proteína digestível (23, 24, 26 e 28 % PD) fornecidas aos juvenis de surubim (157,35± 11,23g) durante cinco meses. Os parâmetros de crescimentos, composição do filé, enzimas metabólicas hepáticas e morfometria do intestino e fígado foram analisados em delineamento inteiramente casualizado com quatro tratamentos e quatro repetições. O aumento de proteína na dieta proporcionou melhor ganho em peso. As enzimas do metabolismo hepático aumentaram nos peixes alimentados com 24%PD. Não foram observadas alterações histopatológicas no fígado dos peixes. A histologia do intestino revelou adaptação ao aumento de proteína na dieta até o nível de 26% PD. Os juvenis de surubim mostraram-se exigentes em proteína digestível, apresentando os melhores resultados de desempenho de produção e de eficiência de utilização dos nutrientes com a dieta contendo 28% de PD.

Influência do tempo de transporte para juvenis de pacamã (Lophiosilurus alexandri) / Influence of transport time on pacama juveniles (Lophiosilurus alexandri)

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.(AU)

Influência do tempo de transporte para juvenis de pacamã (Lophiosilurus alexandri) / Influence of transport time on pacama juveniles (Lophiosilurus alexandri)

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.

Crude protein requeriment to pacamã juveniles / Exigência de proteína bruta para juvenis de pacamã

Pacamã (Lophiosilurus alexandri) is a species of carnivorous fish, suitable for farming, but little studied. The aim of this study was to determinate crude protein (CP) requirement to pacamã, L. alexandri, in juvenile phase, an experiment was conducted during 45 days in a completely randomized design, with five treatments (36.2, 38.2, 42.0, 44.4, and 48.8% CP of diet) and four replications, where a hundred juvenile fishes (5.19 ± 0.01 g) were distributed in twenty 36 L aquaria. Each aquarium with five juveniles was considered an experimental unit. The parameters evaluated were final weight, percentage weight gain, specific growth rate, survival rate, hepatosomatic index, carcass yield with and without head, total length, head length, width, and height. By the regression analysis was verify a (P<0.01) linear decrease to performance parameters in function to ration protein growth, however to Tukey test the best (P<0.01) result was obtained with 36.2% of CP. There was no influence of treatments on the other evaluated parameters (p>0.05). Thus, it is recommended to use feed containing 36.2% of crude protein to pacamã (L. alexandri) juveniles.(AU)

O pacamã (Lophiosilurus alexandri) é uma espécie de peixe com hábito alimentar carnívoro, apropriada para o cultivo, porém, ainda pouco estudada. O objetivo deste estudo foi determinar a exigência de proteína bruta (PB) do pacamã, L. alexandri, na fase juvenil. O experimento foi conduzido por um período de 45 dias utilizando um delineamento inteiramente casualizado, com cinco tratamentos (dieta contendo 36,2; 38,2; 42,0; 44,4 e 48,8% de PB) e quatro repetições cada, onde 100 juvenis (5,19 ± 0,01g) foram distribuídos em 20 caixas com volume útil de 36 L, sendo considerada como unidade experimental uma caixa com cinco juvenis. Foram avaliados os parâmetros de peso final, percentagem de ganho de peso, taxa de crescimento específico, sobrevivência, índice hepatossomático, rendimento de carcaça com e sem cabeça, comprimento total, comprimento da cabeça, largura e altura. Pela análise de regressão foi verificada uma redução linear (P<0.01) nos parâmetros de desempenho em função do nível protéico da ração. Quando comparados pelo teste de Tukey, o melhor resultado (P<0.01) foi obtido com 36,2% de PB. Não houve influência dos tratamentos nos outros parâmetros avaliados (p>0,05). Deste modo, recomenda-se a utilização de rações contendo entre 36,2% de proteína bruta para juvenis de pacamã (L. alexandri).(AU)