The objects of this study were to investigate the differences of total mercury(THg), organic mercury(OHg) concentrations in the muscles of albacore and bigeye tuna from the Pacific Ocean, and the THg and OHg concentration in the livers , and the trace elements (Cu, Fe, Mn and Zn) in the muscles and livers of albacore, in order to evaluate the bioaccumulative status of the oceanic migratory fishes. Meanwhile, The relationships between mercury concentration and size (length and weight) and age were established, and the differences of mercury concentrations in the tuna between species and geography were examined. And that the safety consumption level was also discussed. One hundred eighty-five albacore and 134 bigeye tuna were sampled from the period October 2001 to April 2006 and from September 2005 to November 2006, respectively, in the Western and Central Pacific Ocean. The results showed that the average THg (mg/kg flesh wt.) and OHg (mg/kg flesh wt.) of muscles were 0.435¡Ó0.145 and 0.279¡Ó0.087, respectively, for albacore, and 0.935¡Ó0.655 and 0.544¡Ó0.396, respectively, for bigeye tuna. The THg and OHg of livers of albacore were 0.426¡Ó0.363 and 0.193¡Ó0.121, respectively. The average OHg percentages of the THg in albacore and bigeye tuna were 67¡Ó19 % and 62¡Ó20 %, respectively. Except there was no significant correlation between OHg and age in the liver of albacore, the THg and OHg in the muscles, and THg in the livers of albacore, and THg in the muscles of bigeye tuna showed a positive correlation with size and age. The THg and OHg levels in the muscles of albacore were lower than those of bigeye tuna, and the accumulative rates of THg and OHg in albacore were lower than those in bigeye tuna. No significant different of muscles-THg and -OHg concentrations of albacore from the four samplind areas. However, the THg and OHg levels in muscle of bigeye tuna showed that north group higher than those in equator. The concentrations of THg were similar in muscle and liver of albacore, but those OHg, Cu, Fe, Mn and Zn concentrations in liver were significantly higher than those in muscle. A detoxificated mechanism may be commenced when the concentration of THg in liver of albacore exceed 0.8 mg/kg, to maintain the muscle concentration of THg at a level about 0.7 mg/kg. The OHg concentrations of all albacore and 88% of bigeye tuna were below WHO food safety standard for migratory fishes(1.0 mg/kg). The consumption amount of albacore and bigeye tuna were no more than 300 and 150g, respectively, will not exceesed the PTWI(provisional tolerable weekly intake) set by WHO, that will not cause any health threat for consumer.

Increasing consumer demand for fresh fishery products with minimized loss of their nutritional properties is forcing food industry to look for alternative technologies to maintain the fresh attributes, stability and safety of foods. Demand for fresh tuna fish is no exception, being a valuable source of nutrients with immense health benefits. However, this product is highly perishable and has been commonly implicated in scombroid (histamine) poisoning caused by microbial decarboxylation of histidine contained in high levels in the tissues of scombroid fishes. Current techniques are inadequate for the prevention of histamine formation in fresh fishery products and high pressure processing is a potential alternative for it can inactivate microorganisms and enzymes, without affecting (or only minimally altering) the quality characteristics of foodstuffs. Previous studies have shown a decrease in histamine formation after a high pressure treatment and this study focuses on the effect of high pressure on the histidine decarboxylase enzyme and selected histamine forming microorganisms involved in histamine formation. / Commercial histidine decarboxylase suspended in different media (buffer solution and fish slurry with and without added histidine) was submitted to different high pressure treatments (200--400 MPa) with distinct time durations (0--60 min) at room temperature (20°C--25°C). Enzymatic activity of pressure treated and control samples were then compared by measuring histamine formation. Results were similar in all media; a 200 MPa treatment increased the enzymatic activity a little more than 20% as time increased; a 300 MPa treatment increased activity over 20% at first, followed by a decrease in activity as time increased only to reach a level of residual activity similar or only slightly lower than control samples; and a 400 MPa treatment reduced enzyme activity as time increased to a level of 55% residual activity in a buffer solution where the greatest inactivation was observed. / Enzyme activation and inactivation were affected by a dual effect attributed to a pulse effect, which caused a shift in activity and was independent of the length of the treatment, and a pressure-hold effect, during which activation or inactivation followed first order kinetics. The enzyme appeared highly resistant to pressure in all media as observed from D-values (>2700 min) and pressure sensitivity of destruction rate (zp) values (>500 MPa). / Inactivation of non-pathogen histamine forming bacteria (HFB) Escherichia coli K12 and Bacillus megaterium was evaluated by inoculating cultures in a fish tissue homogenate. Surviving colonies were enumerated after the treatments observing inactivation described by the same dual effect described earlier. Pressures above 300 MPa achieved a significant destruction of E. coli K12 (> 4 log-cycles) while B. megaterium appeared highly resistant for only a 2 log-cycle reduction was observed after at the highest pressure treatment conditions (400 MPa, 20 min). / D-values for both microorganisms decreased as pressure increased being significantly smaller for E. coli K 12, which also appeared to be more sensitive to pressure changes as observed from the zp values (zp = 151.51 MPa and zp = 909.10 MPa for E. coli and B. megaterium respectively. Inactivation caused by the pulse effect appeared very effective for both microorganisms as pressure increased, particularly at 400 MPa (PE > 1.25).

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

El presente trabajo de investigación tiene como propósito realizar un análisis situacional de las exportaciones de pulpa de tuna congelada peruana al mercado de Estados Unidos durante el periodo 2013-2017. Por ello en el primer capítulo, se realiza un repaso de la literatura que va desde el origen, definición y producción del fruto de la tuna; hasta los procesos que conlleva la exportación de esta. Por otro lado, se estudia la situación del mercado estadounidense, ya que este ha sido el destino de exportación por excelencia de la pulpa de tuna peruana congelada. El segundo capítulo aborda la metodología de investigación, la cual describe los objetivos, problemas e hipótesis; así como también a los grupos de actores a entrevistar. Para la estructuración de la información hemos utilizado como guía el PENX 2025. El tercer capítulo muestra el análisis de datos y resultados de cada grupo de actores de acuerdo con la segmentación realizada y en el cuarto capítulo se discuten los resultados obtenidos. Finalmente, en el quinto capítulo se describen las conclusiones y recomendaciones de la investigación. / The purpose of this research is to develop a situational analysis of Peruvian frozen prickly pear puree exports to the US market during period 2013-2017. Therefore, the first chapter reviews the literature which goes from the origin, definition and production of the prickly pear fruit to the processes that entails the export of the final product. On the other hand, it is also reviewed the situation of the US market since it has been the export destination par excellence of the Peruvian frozen prickly pear pulp. The second chapter approaches the research methodology, which describes the objectives, problems and hypotheses; as well as the groups of actors interviewed. For the structuring of the information we have used the PENX 2025 as a guideline. The third chapter shows the data analysis and results of each group of actors according to the segmentation and in the fourth chapter obtained results are discussed. Finally, the fifth chapter describes the conclusions and recommendations of our investigation. / Tesis

Memoria para optar al Título Profesional de Ingeniero Agrónomo / Debido a la estacionalidad y escasez del recurso hídrico en la región de Coquimbo, se llevó a cabo un estudio en micro-lisímetros con plantas de 1 año de granado, higuera y tuna, cuyos objetivos fueron: determinar la eficiencia en el uso del agua estacional (EUA), la eficiencia en el uso del agua normalizada o “kDPV” y la eficiencia en el uso de la radiación (EUR), con el fin de demostrar que aquellas especies poseen bajo consumo hídrico y serían una buena alternativa para la producción frutícola en zonas áridas. La EUA y EUR son parámetros muy útiles para ser utilizados en zonificación agrícola, sin embargo, diversas investigaciones demuestran que son parámetros clima-dependientes resultando compleja una comparación directa entre distintos estudios, debido a esto, se han buscado formas de normalizarlas principalmente con el déficit de presión de vapor de la atmosfera (DPV). Los resultados obtenidos de EUA y kDPV para granado, higuera y tuna en esta investigación fueron respectivamente: 4,70; 3,97 y 18,57 (g [MS] kg-1 [H2O]); 3,3; 2,86 y 6,48 (g [MS] kPa kg-1 [H2O]) y la EUR para granado e higuera (no se evaluó en tuna) fue 2,59 y 2,39 (g [MS] MJ-1 ) respectivamente. También se evaluó la variabilidad de la EUA en función de parámetros climáticos, a través de la eficiencia en el uso del agua instantánea (EUAi), por medio de un analizador de gases infrarojo (IRGA) en granado e higuera (no se evaluó en tuna), la cual, disminuye para ambas especies en condiciones de alto DPV, temperatura de la hoja (Thj) y radiación solar. Se concluye que granado, higuera y tuna son una alternativa para zonas áridas y que la EUAi presenta una relación exponencial negativa con parámetros climáticos como DPV, Thj y PAR. / Because of seasonal and water scarcity in the Region of Coquimbo, a study was conducted on one year old plants of pomegranate, prickly pear and fig grown in micro-lysimeters with the goal of estimating their seasonal water use efficiency (WUE), normalized water use efficiency or “kDPV”, and their radiation use efficiency (RUE). The purpose was to demonstrate that such species have low water consumption and would be an alternative to fruit productions in semi-arid zone. Parameters as WUE and RUE, are very useful for agricultural zoning, however, several studies have shown that they are climate-dependent, which makes it difficult to perform direct comparisons between different studies. Therefore, ways to normalized theses parameters have been sought, mainly using the vapor pressure deficit (VPD) of the atmosphere. In this research, WUE results for pomegranate, prickly pear, and fig were 4,70; 18,57 and 3,97 (g [MS] kg-1 [H2O]), respectively; for kDPV results were 3,3; 6,48 and 2,86 (g [MS] kPa kg-1 [H2O]), respectively; and for RUE they were 2,59 and 2,39 (g [MS] MJ-1), for pomegranate and fig, respectively (not evaluated in prickly pear). The variability of WUE as affected by climatic parameters was assessed via the instant water use efficiency (WUEi) obtained with an infrared gas analyzer (IRGA) in pomegranate and fig (not evaluated in prickly pear); the WUEi decreased in both species under high VPD, leaf temperature (Thj) and solar radiation conditions. It was concluded that pomegranate, prickly pear and fig are an alternative for the semi-arid zones and WUEi presents a negative exponential relationship with climatic parameters as VPD, Thj and solar radiation.

Made available in DSpace on 2016-06-07T17:12:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-02-25. Added 1 bitstream(s) on 2016-06-07T17:16:41Z : No. of bitstreams: 1 000859133_20170225.pdf: 410628 bytes, checksum: f81a73f11d88719a3c6335c8a9339361 (MD5) Bitstreams deleted on 2017-03-03T11:01:35Z: 000859133_20170225.pdf,. Added 1 bitstream(s) on 2017-03-03T11:02:43Z : No. of bitstreams: 1 000859133.pdf: 2180235 bytes, checksum: f0bce47e04dacf3bf05a4c88d59fb720 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Os atuns, bonitos e cavalas são peixes marinhos pelágicos distribuidos em todos os oceanos tropicais e subtropicais do mundo. São frequentemente capturados e comercializados ao longo de toda sua área de distribuição sendo as oito espécies do gênero Thunnus as de maior valor comercial. A correta identificação das espécies, assim como a delimitação de suas populações são de muita importância na pesca, permitindo a tomada de melhores decisões sobre políticas pesqueiras e conservação. Os resultados são discutidos em dois capítulos, o primeiro baseado na identificação das espécies dentro da família Scombridae e o segundo testando análises populacionais em duas espécies de atuns Thunnus obesus e Katsuwonus pelamis, frequentemente capturados no Brasil e Peru. Para isto testamos a eficiência da metodologia do DNA barcode e a amplificação da região controle na identificação das espécies pertencentes à familia Scombride, com ênfase no gênero Thunnus, e a identificação e separação das populações dos dois atuns. Vinte espécies foram analisadas com o COI (648 espécimes) e dezoito com o D-loop (313 espécimes). Para a primeira parte do estudo, o gene COI discriminou 66% das espécies analisadas, mas as pertencentes ao gênero Thunnus não puderam ser separadas, diferente dos resultados encontrados no D-loop onde todas as espécies foram adequadamente separadas, sendo uma ferramenta eficiente para a identificação das espécies da família Scombridae, incluindo o gênero Thunnus. Nas análises populacionais (segundo capítulo) com o uso do D-loop foi possível identificar duas populações de T. obesus (Pacífico e Atlântico), com um valor alto de Fst, fortemente estruturado e estatisticamente significativo e também de duas populações de Katsuwomus pelamis (clado I e clado II) mas nesse segundo caso não foi verificada um isolamento geogrático das populações / Tunas, bonitos and mackerels are marine pelagic fishes distributed in the tropical and subtropical oceans of the world. They are highly captured and traded throughout their distribution area being the eight species of the genus Thunnus those with higher commercial value. Correct species identification in fisheries is needed to take better conservation measures and efficient fisheries management. The results are discussed in two chapters, the first based on the identification of the species within the family Scombridae and the second testing population analysis in two species of tuna Katsuwonus pelamis and Thunnus obesus, offen captured in Brazil and Peru. For this, test the efficiency of the DNA barcode methology and amplification of the control region of species of the Scombridae family, with emphasis in the genus Thunnus, and the identification and separation of the populations of two tuna. Twenty species were analyzed with the COI (648 specimens) and eighteen with the D-loop (313 specimens). For the first part of the study, the COI gene discriminated 66% of the analyzed species, but those belonging to the genus Thunnus could not be separated, unlike the results found in the D-loop in which all species were properly separated and powerful tool for species identification of the Scombridae family, including genus Thunnus. In the population analysis (second chapter) using the D-loop was possible to identify two populations of T. obesus (Pacific and Atlantic), with a high value of Fst, highly structured and statistically significant and also of two populations of K.pelamis (clade I and clade II), but in this second case has not been verified a geographical isolation of populations / FAPESP: 2011/00881-1

Orientador: Claudio de Oliveira / Banca: Anderson Luis Alves / Banca: Luis Henrique Garcia Pereira / Banca: Cristiane Kioko Shimabukuru Diaz / Banca: Alexandre Hisdorlf / Resumo: Os atuns, bonitos e cavalas são peixes marinhos pelágicos distribuidos em todos os oceanos tropicais e subtropicais do mundo. São frequentemente capturados e comercializados ao longo de toda sua área de distribuição sendo as oito espécies do gênero Thunnus as de maior valor comercial. A correta identificação das espécies, assim como a delimitação de suas populações são de muita importância na pesca, permitindo a tomada de melhores decisões sobre políticas pesqueiras e conservação. Os resultados são discutidos em dois capítulos, o primeiro baseado na identificação das espécies dentro da família Scombridae e o segundo testando análises populacionais em duas espécies de atuns Thunnus obesus e Katsuwonus pelamis, frequentemente capturados no Brasil e Peru. Para isto testamos a eficiência da metodologia do DNA barcode e a amplificação da região controle na identificação das espécies pertencentes à familia Scombride, com ênfase no gênero Thunnus, e a identificação e separação das populações dos dois atuns. Vinte espécies foram analisadas com o COI (648 espécimes) e dezoito com o D-loop (313 espécimes). Para a primeira parte do estudo, o gene COI discriminou 66% das espécies analisadas, mas as pertencentes ao gênero Thunnus não puderam ser separadas, diferente dos resultados encontrados no D-loop onde todas as espécies foram adequadamente separadas, sendo uma ferramenta eficiente para a identificação das espécies da família Scombridae, incluindo o gênero Thunnus. Nas análises populacionais (segundo capítulo) com o uso do D-loop foi possível identificar duas populações de T. obesus (Pacífico e Atlântico), com um valor alto de Fst, fortemente estruturado e estatisticamente significativo e também de duas populações de Katsuwomus pelamis (clado I e clado II) mas nesse segundo caso não foi verificada um isolamento geogrático das populações / Abstract: Tunas, bonitos and mackerels are marine pelagic fishes distributed in the tropical and subtropical oceans of the world. They are highly captured and traded throughout their distribution area being the eight species of the genus Thunnus those with higher commercial value. Correct species identification in fisheries is needed to take better conservation measures and efficient fisheries management. The results are discussed in two chapters, the first based on the identification of the species within the family Scombridae and the second testing population analysis in two species of tuna Katsuwonus pelamis and Thunnus obesus, offen captured in Brazil and Peru. For this, test the efficiency of the DNA barcode methology and amplification of the control region of species of the Scombridae family, with emphasis in the genus Thunnus, and the identification and separation of the populations of two tuna. Twenty species were analyzed with the COI (648 specimens) and eighteen with the D-loop (313 specimens). For the first part of the study, the COI gene discriminated 66% of the analyzed species, but those belonging to the genus Thunnus could not be separated, unlike the results found in the D-loop in which all species were properly separated and powerful tool for species identification of the Scombridae family, including genus Thunnus. In the population analysis (second chapter) using the D-loop was possible to identify two populations of T. obesus (Pacific and Atlantic), with a high value of Fst, highly structured and statistically significant and also of two populations of K.pelamis (clade I and clade II), but in this second case has not been verified a geographical isolation of populations / Doutor

Memoria para optar al título profesional de Ingeniera en Recursos Naturales Renovables / En los últimos años, la utilización de energías renovables no convencionales ha alcanzado gran importancia tanto a nivel mundial como nacional, generando el interés de encontrar nuevas alternativas para la aplicación de energías renovables. La presente memoria investiga sobre las plantaciones de tunales como fuente de materia prima para la generación de biogás, así como también estima su potencial de producción en el norte chico de Chile. El biogás es una alternativa energética para el sector agropecuario, el cual es obtenido mediante bioprocesos de fermentación de diversos residuos y desechos que se producen diariamente. Además de generarse biogás, se obtiene un residuo estabilizado, el cual puede ser incorporado al suelo. Esto constituye una alternativa para las zonas áridas y semiáridas del norte chico de Chile debido a que son suelos pobres en materia orgánica, y por lo tanto, presentan alto grado de deficiencia en sus propiedades físicas, químicas y biológicas, limitando la plantación de cualquier tipo de cultivo. La tuna (Opuntia ficus indica) es una especie que se adapta fácilmente a este tipo de situaciones, ya que logra modificarse según características del terreno y del clima del sector. Un ejemplo es la forma de su tallo que se modifica de acuerdo al manejo cultural que se le otorgue y según el clima. Posee un sistema radical superficial carnoso que favorece la absorción de agua que se encuentre cercana a la superficie. Su metabolismo CAM le permite adaptarse a sequías, permaneciendo sus estomas cerrados durante todo el día y toda la noche y a lluvias, abriendo sus estomas bien temprano en la mañana. Otra característica importante de esta especie es la gran cantidad de biomasa que genera, llegando a producir 30ton/ha en condiciones de buen manejo cultural y buena disponibilidad de agua. Es por esta característica y por el potencial de generación de biogás que se considera una buena alternativa para el norte chico de Chile. Referente a la elección del digestor a utilizar, ésta dependerá del uso que se le quiera dar y de las condiciones económicas que se tengan. Se tienen estimaciones de la producción de biogás en el norte chico de Chile del orden de 13.406,4m3/kg/día de biogás. Esto se puede mejorar a través de la inclusión de otros residuos presentes en la zona que permitan modificar algunos parámetros determinantes en la generación de biogás. / Renewable energies have reached importance in the past years, not only on a national scale, but also on a global one, finding new applications for the use of renewable energies. This project investigates about prickly plantations as main source for the production of biogas and their energy potential for northern Chile. Biogas is an energy alternative for the agricultural sector and is obtained by fermentation processes of different wastes produced daily. Besides the generation of biogas it is also possible to obtain a stabilized waste that can be incorporated on the soil, meaning an alternative for the dry and semi dry zones of the northern Chile. Because their soil is poor in organic matter content, therefore, presents deficient chemical, physical and biological properties. This makes difficult the implementation of any type of crops. The prickly pear (Opuntia ficus indica) adapts easily to the previous conditions, because it is possible to modify it according to the features of the land and the weather. In example, the form of the stem varies depending on the cultural management and the weather conditions. The specie possesses a superficial fleshy root system that facilitates the absorption of water on the surface. Also, the CAM metabolism allows the adaptability to drought and rains, by closing the stomatas during day and night, and opening them early in the morning. Another important feature of this specie is the biomass production, reaching around 30 ton/ha with good cultural management and water availability. For this reason and for the potential to produce biogas it is considered a good alternative for the northern Chile. To define the best biodigestor to use, this will depend on the use and the costs associated. The estimation of biogas production in the northern Chile is 13.406,4 4 m3/kg/d. This result can be improved adding other wastes produced in the area that allows change some parameters relevant for the production of biogas.

The ability to manage a fish stock relies on an understanding of life history characteristics and basic biology of the species. Numerous age-growth studies are facilitated by the relative ease of ageing fishes through hard-part analyses. Determining reproductive parameters for fish populations is equally important for stock assessments and management, and histological examination of gonads provides the most accurate determination of fecundity and spawning periods. Coastal pelagic fishes are often targeted commercially and recreationally due to their easy access by private vessels. However, there are few studies researching the biology and reproduction of recreational fishes in the waters of Southeastern Florida that would lead to a better understanding for management practices. The objective of this study was to provide baseline reproductive data for two fishes particularly important to Florida fisheries: the coastal pelagic scombrids Blackfin Tuna Thunnus atlanticus and Little Tunny Euthynnus alletteratus. Archived gonad samples from 2010-2014 for these two species were evaluated, and GSI values and histological examination indicated one spawning season for both species. Little Tunny spawn April through August, and Blackfin Tuna spawn May through June. Additionally both species have asynchronous oocyte development, and are batch spawners. Postovulatory follicles were used to estimate spawning frequency; for Blackfin Tuna, mean spawning occurs once every 1.49 days, and for Little Tunny, mean spawning occurs once every 1.47 days. Comparison of otolith age data to these results indicates that Little Tunny mature at a smaller size and younger age than Blackfin Tuna. Size at 50% maturity for male Blackfin Tuna was 435.2 mm TL, for female Blackfin Tuna was 392.3 mm TL, and for male Little Tunny was 347.77 mm TL. Age at 50% majority for male Blackfin Tuna was 0.66 years, and for male Little Tunny was 0.50 years. In addition to providing important baseline data for fisheries management, this study collaborated with previous research to improve accuracy of reproductive age assessments. Finally, reproductive parameter studies of fishes in Florida and the Greater Caribbean area commercial and recreational fisheries provide information important for future ecosystem based management.

A exigência de alimento proteico palatável e de alto valor nutricional torna a dieta dos peixes carnívoros altamente dependente de farinha de peixe [FP], alimento de alto custo e já escasso no mercado. Hidrolisados de subprodutos da indústria animal são alimentos de alta qualidade que podem ser usados para substituir a FP nas dietas para peixes. Este trabalho foi realizado em dois ensaios: o primeiro avaliou a digestibilidade de hidrolisados de resíduos de tilápia [RTI], cabeças de atum [CAT], fígados de suínos [FSU] e de aves [FAV] e a influência da inclusão dos hidrolisados nas dietas no perfil de enzimas digestivas nos estômagos, cecos pilóricos e intestinos de juvenis (39,73 ± 5,30 g) do Characiforme carnívoro dourado, Salminus brasiliensis; o segundo ensaio avaliou o desempenho de juvenis de dourados (4,57 ± 1,25 g) alimentados com níveis crescentes de inclusão de FSU (0, 70, 140, 210 e 280 g kg-1) na dieta. A inclusão dos hidrolisados na formulação das dietas diminuiu o pH das rações mas não interferiu no consumo pelos peixes. Os maiores coeficientes de digestibilidades dos nutrientes foram registrados em peixes alimentados com as dietas contendo RTI e FSU, enquanto os menores foram encontrados para aqueles alimentados com as dietas contendo CAT. A atividade da protease e da lipase foi maior nos estômagos dos animais, em especial aqueles que foram alimentados com a dieta contendo FSU. A atividade de amilase foi maior nos cecos pilóricos, enquanto nos intestinos foi registrada maior atividade nas dietas controle e RTI. Hidrolisados de subprodutos da indústria animal foram altamente digestíveis para dourados e o perfil enzimático dos peixes foi dependente dos nutrientes da dieta. No segundo ensaio os menores valores de ingestão diária foram registrados nos peixes alimentados com a dieta sem inclusão de hidrolisado, mas os menores valores de ganho de peso, peso final e das taxas de crescimento específico, de eficiência proteica e energética, e de retenção proteica foram registrados nos peixes alimentados com a dieta contendo 280 g kg-1 de hidrolisado suíno. A grande proporção de aminoácidos livres e pequenos peptídeos nas dietas com inclusões acima de 140 g kg-1 do produto aparentemente reduziu a síntese de proteínas dos animais. A saúde dos peixes não foi afetada significativamente pela inclusão de hidrolisados na dieta, porém, aparentemente, os peixes alimentados com dietas contendo até 140 g kg-1 de hidrolisado tiveram melhores índices imuno-hematológicos. / Carnivorous fish diets strongly depend on fish meal (FM), a high-cost, scarce feedstuff, given the need for palatable protein and high nutritious value. Animal by-product hydrolysates are high-quality feedstuff that can substitute FM in fish diets. This study evaluated digestibility of hydrolysates from tilapia residue [TR], tuna head [TH], swine liver [SL] and poultry liver [PL], and the profile of digestive enzymes in the stomachs, pyloric cecum and intestines of juvenile (39,73 ± 5,30 g) dourado, Salminus brasiliensis, a carnivorous Characin fed diets containing graded levels of hydrolysates, and the performance of juvenile dourado (4,57 ± 1,25 g) fed diets containing increasing levels of FSU (0, 70, 140, 210 and 280 g kg-1). The addition of hydrolysates to diets lowered the pH of feed, but did not alter feed intake by fish. Higher digestibility coefficients of nutrients were recorded for fish fed diets containing TR and SL, and the lower for those fed diets containing TH. Protease and lipase activity in the fish\'s stomach was higher, especially for those fed diets containing SL. Amylase activity was higher in pyloric caeca, while in the intestines the higher activity was registered for fish fed control and TR diets. Animal by-product hydrolysates were highly digestible for dourado, and enzymatic profile of fish depended on nutrients of diets. In the second trial, the lowest values of daily intake were recorded for fish fed diet without inclusion of hydrolysate. However, the lowest weight gain, final weight and specific growth rate, protein and energy efficiency, and protein retention rates were recorded for fish fed diet with 280 g kg-1 of swine hydrolysate. The large proportion of free amino acids and small peptides in the diets with inclusions above 140 g kg-1 of the product apparently reduced the protein synthesis by fish. Health status of fish was not significantly affected by dietary hydrolysates, but apparently, fish fed diets containing more than 140 g kg-1 had better immuno-hematological indices.