Foliculogénesis en Rhinella bergi (Anura: Bufonidae)

Los anuros muestran la mayor diversidad de modos reproductivos que cualquier otro grupo de vertebrados, constituyendo así un taxón muy interesante para los estudios de biología reproductiva. Los factores exógenos como la temperatura del aire, el fotoperiodo y las precipitaciones; y endógenos, como la regulación neuroendócrina de hormonas hipofisiarias y esteroideas, condicionan la actividad gonadal y sus ciclos reproductivos. Por tal motivo, el objetivo del presente trabajo es analizar la foliculogénesis en Rhinella bergi mediante el análisis anatómico e histológico de los ovarios, con el fin de contribuir al conocimiento de los eventos claves de la foliculogénesis, para la posterior comparación con otras especies de anuros neotropicales. Para ello se recolectaron ejemplares de R. bergi en viajes de campo a la localidad de La Leonesa (Departamento Bermejo, Chaco - Argentina) durante el año 2014, los cuales fueron llevados al laboratorio y sometidos éticamente a eutanasia para la disección del aparato reproductor y fijación en formol al 10%. Para el análisis macroscópico del sistema gonadal, se procedió a la disección de los animales y posterior observación bajo microscopio estereoscópico. Para el análisis tisular del ovario, se realizaron preparados histológicos siguiendo las técnicas convencionales de deshidratación, inclusión en parafina, cortes en micrótomo y coloración. Las muestras fueron coloreadas con Hematoxilina- Eosina (H-E) para la caracterización histológica general. El ovario de Rhinella bergi exhibe el mismo patrón estructural que el resto de los anuros, compuesto de una corteza y médula, cubierto por una fina capa incolora de tejido conectivo. A nivel histológico se compone de diferentes tipos celulares de la línea germinal: folículos previtelogénicos, vitelogénicos y post- vitelogénicos. Algunos ovarios analizados presentaron folículos atrésicos, tanto en estado previtelogénico como posvitelogénico. Dicho proceso es común en ovarios de anuros, en los cuales se observa que durante el proceso de ovulación, no todos los folículos llegan a atravesar el oviducto. Estos resultados sientan las bases para la caracterización del ciclo reproductivo de la especie en estudio, como así también para futuros análisis comparativos con otras especies de anuros de nuestra región.Fil: Cheij, Esteban Omar. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; ArgentinaFil: Rodriguez, Florencia Evelyn. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Química Básica y Aplicada del Nordeste Argentino. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Química Básica y Aplicada del Nordeste Argentino; ArgentinaFil: Cespedes, Jorge. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; ArgentinaFil: Flores Quintana, Carolina Isabel. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; ArgentinaX Jornadas de Jóvenes InvestigadoresBuenos AiresArgentinaUniversidad de Buenos Aires. Facultad de Ciencias Veterinaria

Ovarían morphology andfolliculogenesis in Gymnotus carapo (Linnaeus, 1758)

El objetivo del presente trabajo fue el estudio de la morfología ovárica y la foliculogénesis de Gymnotus carapo, a fin de aportar información sobre su biología reproductiva, y que ésta sea de utilidad en el manejo de dicha especie como recurso pesquero. Se recolectaron 40 ejemplares hembras durante el periodo de febrero a diciembre del 2019 en ambientes naturales próximos a la Ciudad de Corrientes. Posteriormente a la captura fueron anestesiados con solución de lidocaína al 2% y sacrificados por sección medular. Los ovarios fueron aislados y fijados en formol al 10%; posteriormente fueron procesados para la técnica histológica convencional y coloreados con hematoxilina-eosina (H-E), tricrómica de Gomori y reacción histoquímica de PAS. Los preparados histológicos fueron analizados a través del microscopio óptico. Se pudo observar que la foliculogénesis en G. carapo es similar a la descrita para otros peces. El ovario y los ovocitos de G. carapo experimentan diferentes etapas de desarrollo: crecimiento primario, secundario, vitelogénesis y maduración durante el ciclo reproductivo, información que sienta base para estudios futuros sobre biología reproductiva. La información brindada en el presente trabajo es importante dado que aporta un estudio histológico detallado que describe la morfología ovárica y foliculogénesis en G. carapo y contribuye a la gestión y planificación de conservación de especies de importancia para el recurso pesquero.The objective of this work is to study the ovarian morphology and folliculogenesis of Gymnotus carapo, in order to provide information on its reproductive biology, and that this is useful in the management of this species as a fishing resource. 40 female specimens were collected during the period from February to December 2019 from natural environments near the City of Corrientes. After capture, they were anesthetized with 2% lidocaine solution and sacrificed by spinal section. The ovaries were isolated and fixed in 10% formalin; Later they were processed for the conventional histological technique and stained with hematoxylin-eosin (H-E), Gómori trichrome and PAS histochemical reaction. The histological preparations were analyzed through the light microscope. It was observed that the folliculogenesis in G. carapo is similar to that described for other fish. The ovary and oocytes of G. carapo undergo different stages of development: primary and secondary growth, vitellogenesis and maturation during the reproductive cycle, information that provides the basis for future studies on reproductive biology. The information provided in this work is important since it provides a detailed histological study that describes the ovarian morphology and folliculogenesis in G. carapo and contributes to the management and conservation planning of species that are of importance to the fishing resource.Fil: Perez, Dante David. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; ArgentinaFil: Olea, Gabriela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; Argentina. Universidad Nacional del Nordeste. Facultad de Medicina; Argentina. Universidad Nacional del Chaco Austral; ArgentinaFil: Mendez Galarza, Sabrina. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; ArgentinaFil: Blanco Cohene, Tania Katherina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; ArgentinaFil: Flores Quintana, Carolina Isabel. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; Argentina. Universidad Nacional del Chaco Austral; Argentin

Ovarían morphology andfolliculogenesis in Gymnotus carapo (Linnaeus, 1758)

El objetivo del presente trabajo fue el estudio de la morfología ovárica y la foliculogénesis de Gymnotus carapo, a fin de aportar información sobre su biología reproductiva, y que ésta sea de utilidad en el manejo de dicha especie como recurso pesquero. Se recolectaron 40 ejemplares hembras durante el periodo de febrero a diciembre del 2019 en ambientes naturales próximos a la Ciudad de Corrientes. Posteriormente a la captura fueron anestesiados con solución de lidocaína al 2% y sacrificados por sección medular. Los ovarios fueron aislados y fijados en formol al 10%; posteriormente fueron procesados para la técnica histológica convencional y coloreados con hematoxilina-eosina (H-E), tricrómica de Gomori y reacción histoquímica de PAS. Los preparados histológicos fueron analizados a través del microscopio óptico. Se pudo observar que la foliculogénesis en G. carapo es similar a la descrita para otros peces. El ovario y los ovocitos de G. carapo experimentan diferentes etapas de desarrollo: crecimiento primario, secundario, vitelogénesis y maduración durante el ciclo reproductivo, información que sienta base para estudios futuros sobre biología reproductiva. La información brindada en el presente trabajo es importante dado que aporta un estudio histológico detallado que describe la morfología ovárica y foliculogénesis en G. carapo y contribuye a la gestión y planificación de conservación de especies de importancia para el recurso pesquero.The objective of this work is to study the ovarian morphology and folliculogenesis of Gymnotus carapo, in order to provide information on its reproductive biology, and that this is useful in the management of this species as a fishing resource. 40 female specimens were collected during the period from February to December 2019 from natural environments near the City of Corrientes. After capture, they were anesthetized with 2% lidocaine solution and sacrificed by spinal section. The ovaries were isolated and fixed in 10% formalin; Later they were processed for the conventional histological technique and stained with hematoxylin-eosin (H-E), Gómori trichrome and PAS histochemical reaction. The histological preparations were analyzed through the light microscope. It was observed that the folliculogenesis in G. carapo is similar to that described for other fish. The ovary and oocytes of G. carapo undergo different stages of development: primary and secondary growth, vitellogenesis and maturation during the reproductive cycle, information that provides the basis for future studies on reproductive biology. The information provided in this work is important since it provides a detailed histological study that describes the ovarian morphology and folliculogenesis in G. carapo and contributes to the management and conservation planning of species that are of importance to the fishing resource.Fil: Perez, Dante David. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; ArgentinaFil: Olea, Gabriela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas, Naturales y Agrimensura. Departamento de Biología; Argentina. Universidad Nacional del Nordeste. Facultad de Medicina; Argentina. Universidad Nacional del Chaco Austral; ArgentinaFil: Mendez Galarza, Sabrina. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; ArgentinaFil: Blanco Cohene, Tania Katherina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; ArgentinaFil: Flores Quintana, Carolina Isabel. Universidad Nacional del Nordeste. Facultad de Cs.veterinarias. Departamento de Cs.basicas. Cátedra de Histología y Embriologia; Argentina. Universidad Nacional del Chaco Austral; Argentin

Torta de pinhão-manso (Jatropha curcas): implicações hepatotóxicas

Jatropha has been highlighted as an oleaginous potential for the production of biofuel. The cake, produced by oil extraction, could be used in animal feed. However, some varieties of jatropha are toxic by limiting their incorporation into animal diets. The objective of this study was to evaluate the hepatotoxicity of diets added with jatropha cake – JC (Jatropha curcas) in rats. Thirty-five (35) male Wistar adults rats (Rattus norvegicus) with initial weight of 352.1 ± 26.8 g were used. The animals were fed for 21 days with the diets: control, 10, 25, 40 and 50% JC. In the feeding with 50% JC the animals presented themselves prostrate and with piloerection. Development and survival decreased, since the inclusion of JC in diets increased. In rats submitted to 10 and 25% JC there was an increase of 17.52% in the hepatosomatic index in relation to the control group. Increase of JC in the rat diet promoted an increase in the activity of ALT and AST enzymes. Anatomic-histopathological evaluation demonstrated that, regardless of the levels tested, JC in rat diet causes hypertrophy of the hepatocytes, with a reduction in energy reserves. This study demonstrated that the use of JC resulted in decreased food intake, associated with weight loss due to the clinical pattern of toxicity, demonstrated by biochemical and histopathological changes in the liver. It was concluded that the inclusion of jatropha cake in rat feeding presents high hepatotoxic potential leading to lesions in the liver parenchyma.O pinhão-manso tem se destacado como oleaginosa potencial para a produção de biocombustível. A torta, coproduto da extração do óleo, poderia ser utilizada na alimentação animal. No entanto, algumas variedades de pinhão-manso são tóxicas, limitando sua incorporação em dietas animais. Objetivou-se neste estudo avaliar a hepatotoxicidade de dietas acrescidas de torta de pinhão-manso (Jatropha curcas) em ratos. Foram utilizados trinta e cinco (35) ratos Wistar (Rattus norvergicus) machos adultos com peso inicial de 352,1 ± 26,8 g. Os animais foram alimentados por 21 dias com as dietas: controle, 10, 25, 40 e 50% TPM. Na alimentação com 50% TPM os animais apresentaram-se prostrados e com piloereção. O desenvolvimento e a sobrevivência apresentaram diminuição conforme o aumento da inclusão de TPM nas dietas. Em ratos submetidos a 10 e 25% TPM houve aumento de 17,52% no índice hepatossomático em relação ao grupo controle. O aumento de TPM na dieta de ratos promoveu aumento da atividade das enzimas ALT e AST. A avaliação anatomo-histopatológica revelou que, independentemente dos níveis testados, a TPM na alimentação de ratos provoca hipertrofia dos hepatócitos, com redução das reservas energéticas. Este estudo demonstrou que a utilização de TPM resultou em diminuição do consumo de alimento associado à perda de peso devido ao quadro clínico de toxicidade demonstrado pelas alterações bioquímica e histopatológica no fígado. Conclui-se que a inclusão de torta de pinhão-manso na alimentação de ratos apresenta alto potencial hepatotóxico levando a lesões no parênquima hepático

Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe

Higher COVID-19 pneumonia risk associated with anti-IFN-α than with anti-IFN-ω auto-Abs in children

We found that 19 (10.4%) of 183 unvaccinated children hospitalized for COVID-19 pneumonia had autoantibodies (auto-Abs) neutralizing type I IFNs (IFN-alpha 2 in 10 patients: IFN-alpha 2 only in three, IFN-alpha 2 plus IFN-omega in five, and IFN-alpha 2, IFN-omega plus IFN-beta in two; IFN-omega only in nine patients). Seven children (3.8%) had Abs neutralizing at least 10 ng/ml of one IFN, whereas the other 12 (6.6%) had Abs neutralizing only 100 pg/ml. The auto-Abs neutralized both unglycosylated and glycosylated IFNs. We also detected auto-Abs neutralizing 100 pg/ml IFN-alpha 2 in 4 of 2,267 uninfected children (0.2%) and auto-Abs neutralizing IFN-omega in 45 children (2%). The odds ratios (ORs) for life-threatening COVID-19 pneumonia were, therefore, higher for auto-Abs neutralizing IFN-alpha 2 only (OR [95% CI] = 67.6 [5.7-9,196.6]) than for auto-Abs neutralizing IFN-. only (OR [95% CI] = 2.6 [1.2-5.3]). ORs were also higher for auto-Abs neutralizing high concentrations (OR [95% CI] = 12.9 [4.6-35.9]) than for those neutralizing low concentrations (OR [95% CI] = 5.5 [3.1-9.6]) of IFN-omega and/or IFN-alpha 2

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Suplementação de enzimas exógenas em dieta microparticulada para larvicultura do pacu

Este experimento foi realizado para avaliar os efeitos da suplementação de enzimas exógenas (pancreatina suína) em microdietas sobre o crescimento, a sobrevivência e as alterações morfológicas do trato digestório de larvas de pacu, Piaractus mesopotamicus. Foram testados oito programas alimentares: alimentação exclusiva com náuplios de Artemia (AV); alimentação exclusiva com dieta microparticulada com (DMP) ou sem (DM) suplementação enzimática; substituição, aos cinco dias, dos náuplios de Artemia por dietas inertes com (AV5DMP) ou sem (AV5DM) suplementação; e substituição dos náuplios aos dez dias por dietas com (AV10DMP) ou sem (AV10DM) suplementação. O experimento teve duração de 28 dias. Larvas que receberam o alimento vivo durante todo o período experimental apresentaram maiores médias de peso. O efeito negativo da supressão do alimento vivo sobre o crescimento das larvas foi verificado tanto na substituição aos cinco dias como aos dez dias. No entanto, nas avaliações biométricas subseqüentes, observaram-se efeitos positivos da suplementação enzimática; a partir do 20º dia de experimento, as larvas que receberam a dieta suplementada com enzima exógena apresentaram peso médio estatisticamente superior ao daquelas alimentadas com a dieta sem suplementação. As diferenças morfológicas mais evidentes proporcionadas pela suplementação enzimática foram observadas nas larvas que receberam substituição alimentar aos cinco dias. As diferenças foram relativas à quantidade de grânulos de zimogênio no pâncreas e às inclusões supranucleares no intestino. As larvas submetidas à transição alimentar aos dez dias de experimento já apresentavam diferenciação morfológica do sistema digestório mais avançada, assemelhando-se muito às larvas do tratamento com alimento vivo. Os resultados deste experimento indicam que a suplementação com pancreatina proporcionou efeitos positivos sobre o crescimento e a sobrevivência das larvas de pacu.This experiment aimed to determine the effects of exogenous enzyme (porcine pancreatin) supplementation to microdiet on pacu Piaractus mesopotamicus growth, survival and changes on digestive tract morphology. Eight feeding programs were performed: Artemia nauplii feeding (AV), microdiet with enzymatic supplementation (DMP) or without supplementation (DM), weaning at the 5th day with supplemented (AV5DMP) or not supplemented diet (AV5DM) and weaning at the 10th day with supplemented diet (AV10DMP) or not supplemented diet (AV10DM). The experiment lasted 28 days. Larvae fed only alive prey during the whole period showed the highest mean weight values. The negative effect of Artemia suppression on larvae growth was noted on those which were weaned either on the 5th or 10th day of experiment. However, at the next growth evaluation, positive effects of enzyme supplementation were observed. After the 20th of experiment, the larvae fed exogenous enzyme supplemented diet showed higher mean weight values than larvae fed diet without supplementation. The most noticeable morphological changes between larvae that received the enzyme supplementation or not was observed for larvae weaned at the 5th day of experiment. The differences were on the amount of zymogen granules in the pancreas and intestine supranuclear inclusion. on the other hand, larvae weaned at the 10th of the experiment presented more advanced morphological differentiation, similarly to the larvae fed alive prey. The results of this experiment show positive effects of pancreatin supplementation on pacu larvae growth and survival

Levels of digestible protein to surubim (Pseudoplatystoma sp.) reared in net cages

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.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