Desova induzida de curimatã-pacu submetido a dois protocolos de hipofisação

O objetivo deste trabalho foi comparar dois protocolos de hipofisação, na indução à desova de curimatã-pacu.Testou-se a aplicação de dose única ou duas doses de extrato bruto de hipófise de carpa-comum. Não houve diferença significativa entre os protocolos quanto às taxas de fêmeas que desovaram, fertilização e larvas deformadas. A aplicação de dose única resultou em valores de horas-graus até a extrusão dos ovócitos maiores do que em duas doses. A aplicação de uma única dose representou menor consumode água, energia e tempo. O protocolo da dose única pode ser utilizado como alternativa para a indução à desova de curimatã-pacu.

Gastrointestinal transit of extruded or pelletized diets in pacu fed distinct inclusion levels of lipid and carbohydrate

The objective of this work was to evaluate the effect of pelletized or extruded diets, with different levels of carbohydrate and lipid, on the gastrointestinal transit time (GITT) and its modulation in pacu (Piaractus mesopotamicus). One hundred and eighty pacu juveniles were fed with eight isonitrogenous diets containing two carbohydrate levels (40 and 50%) and two lipid levels (4 and 8%). Four diets were pelletized and four were extruded. Carbohydrate and lipid experimental levels caused no changes to the bolus transit time. However, the bolus permanence time was related to diet processing. Fish fed pelletized diets exhibited the highest gastrointestinal transit time. Regression analysis of bolus behavior for pelletized and extruded diets with 4% lipid depicted different fits. GITT regression analysis of fish fed 8% lipid was fitted to a cubic equation and displayed adjustments of food permanence, with enhanced utilization of the diets, either with extruded or pelletized diets. GITT of fish fed extruded diets with 4% lipid was adjusted to a linear equation. The GITT of pacu depends on the diet processing and is affected by dietary levels of lipid and carbohydrate.

Substituição do milho pelo sorgo em dietas para juvenis de pacu

Resumo: O objetivo deste trabalho foi avaliar o coeficiente de digestibilidade aparente (CDA) de sorgo, e determinar o desempenho produtivo, os índices somáticos, os parâmetros hematológicos e a composição centesimal do filé de pacus alimentados com dietas com diferentes níveis de sorgo, além de avaliar o custo da formulação. Para a determinação do CDA da matéria seca (MS), da proteína bruta (PB), do extrato etéreo (EE) e da energia bruta (EB) do sorgo, utilizaram-se 160 pacus, com peso médio de 56,00±8,04 g, alimentados com dieta-referência e dieta-teste (30% sorgo), acrescidas de 0,1% de óxido de cromo III. Para avaliação do desempenho, utilizaram-se 180 juvenis de pacu (10,80±0,77 g) alimentados com cinco dietas experimentais, em que 0, 25, 50, 75 e 100% da energia do milho foi substituída pela do sorgo. Os CDA do sorgo pelo pacu foram: 78,52% da MS; 74,82% da PB; 94,36% de EE; e 77,24% de EB. Não se observaram diferenças entre as dietas quanto ao desempenho, aos índices somáticos e aos parâmetros hematológicos. Porém, na composição centesimal dos filés, houve diferença entre os tratamentos. O sorgo apresenta CDA semelhante ao do milho e pode substituí-lo integralmente em dietas para juvenis de pacu, além de diminuir o custo da formulação.

Histologia e ultraestrutura do rim e rim cefálico do pacu

O pacu, Piaractus mesopotamicus, é um teleósteo da Família Characidae, intensivamente cultivado no Brasil devido sua rusticidade, crescimento rápido e fácil adaptação. O conhecimento morfológico dos sistemas corpóreos, incluído órgãos linfóide, se faz necessário, para uma melhor produção no cultivo de peixes, fornecendo subsídios na manutenção dos estoques. O objetivo deste estudo foi descrever morfologicamente o rim e rim cefálico de Piaractus mesopotamicus, analisando os perfis celulares de cada órgão com o uso de microscopia de luz e microscopia eletrônica de transmissão. O resultado da análise macroscópica mostrou que a localização do rim e rim cefálico são as mesmas encontradas na maioria dos teleósteos. O rim apresentou uma forma em "H", onde a região média se expandia sobre a bexiga natatória. O rim cefálico se apresentou como uma dilatação na região cranial do rim, mostrando-se bem visível. Na microscopia eletrônica de transmissão também foram observadas similaridades ultraestruturais com outros teleósteos. Observando nossos resultados concluímos que histologicamente e ultraestruturalmente, os órgãos linfóides rim e rim cefálico de Piaractus mesopotamicus são similares aos de outros teleósteos.

Estudo do potencial do pacu (Piaractus mesopotamicus) como agente de controle biológico de Egeria densa, E. najas e Ceratophyllum demersum

Visando fornecer subsídios para elaboração de sistema de manejo integrado das grandes massas de plantas daninhas aquáticas submersas em lagos e represas, o presente trabalho teve como objetivo verificar a eficiência do pacu (Piaractus mesopotamicus) como agente de controle biológico de Egeria densa, E. najas e Ceratophyllum demersum. As espécies de plantas daninhas foram oferecidas individualmente, duas a duas e as três espécies juntas. Verificou-se que este peixe tem uma eficiência média de controle dessas plantas daninhas variando entre 28 e 100%, podendo eliminar uma massa verde dessas plantas, com a mesma quantidade de seu peso, em sete dias. A eficiência de controle diária aumentou com o tempo de predação. O pacu é mais seletivo para E. densa ou E. najas quando na presença de C. demersum. Não ocorreu alteração na eficiência de controle do pacu sobre E. densa ou E. najas em todos os tratamentos e nos três períodos estudados (três, cinco e sete dias).

Plasma testosterone and 11-ketotestosterone levels of male pacu Piaractus mesopotamicus (Cypriniformes, Characidae)

The levels of testosterone (T) and 11-ketotestosterone (11-KT) of the South American pacu Piaractus mesopotamicus were determined by radioimmunoassay during two stages of the reproductive cycle, i.e., resting and maturation, and the gonadosomatic index (GSI) was calculated. The highest levels of T and 11-KT were reached during the maturation stage (T = 2400 ± 56 pg/ml; 11-KT = 2300 ± 60 pg/ml) and lower levels were maintained during the resting period. The rise in androgen levels occurred with the appearance of spermatozoa in the maturation stage, when GSI was highest

Aterações químicas e microbiológicas em PACU (piaractus mesopotamicus) armazenado sob refrigeração a 5°c

A pesquisa foi conduzida com o objetivo de analisar a vida útil e o processo de deterioração do pacu (Piaractus mesopotanicus) armazenado sob refrigeração em temperatura inadequada (5°C). Amostras do pescado, imediatamente após a captura, foram armazenadas a 5°C e analisadas nos intervalos de 0-7-14 e 21 dias, com relação a características sensoriais e de natureza química (bases nitrogenadas voláteis - BNV, nitrogênio não protéico - NNP, aminoácidos livres totais, histidina livre e histamina) e microbiológicos (contagem padrão, produtores de histamina em ágar Niven, contagem de microrganismos gelatinase e H2S positivos, nas temperaturas de 35°C, 20° e 5°C). Os resultados obtidos confirmaram que, a exemplo de outros peixes fluviais de regiões tropicais, o pacu revelou-se bastante resistente ao armazenamento, somente evidenciando uma alteração marcante após 14 dias de estocagem. Assim mesmo, a rejeição do pescado foi baseada principalmente em características sensoriais (odor, aspecto, textura) uma vez que com relação aos índices químicos (BNV) e mesmo microbiológicos, não se caracterizava uma situação definitiva de deterioração e rejeição. Observou-se, também, que o processo de deterioração pareceu concentrar-se principalmente no muco superficial, sendo que as características químicas do tecido muscular não evidenciaram alterações marcantes, mesmo após 21 dias de armazenamento. A presença de histamina não foi positivada nas amostras e os níveis de histidina livre, embora relativamente elevadas, não sugerem maiores riscos desta espécie de peixe como eventual veículo de intoxicação por histamina. No entanto, bactérias his+ foram isoladas das amostras iniciais, entre elas cepas de Plesiomonas shigelloides e Vibrio fluvialis. A microbiota contaminante natural foi reduzida, predominando microrganismos mesófilos/psicrotrófilos, com baixas contagens iniciais a 5°C. Ao longo do armazenamento a 5°C esta microbiota mostrou uma lenta multiplicação, somente sendo alcançadas populações compatíveis com o processo de deterioração (> log7,0 UFC/cm²) após 14 dias de estocagem.

Incorporation of conjugated linoleic acid (CLA) and α-linolenic acid (LNA) in pacu fillets

The objective of this study was to evaluate the incorporation of conjugated linoleic acid and α-linolenic acid in fillets of pacu fish raised in net cages and fed diets enriched with these acids. The fish were fed for 49 days, and at the end of this period the fatty acid content in the fillets was determined by gas chromatography. Concentrations of α-linolenic acid, eicosapentaenoic acid, and the total omega-3 (n-3) fatty acid in the fillets increased, improving the n-6/n-3 ratio. In addition, the incorporation of conjugated linoleic acid in the fish fillets proved well established. This study showed that the use of diets enriched with conjugated linoleic acid and α-linolenic acid results in the incorporation of these acids in the of pacu fish fillets, improving their nutritional quality.

The combined effect of copper and low pH on antioxidant defenses and biochemical parameters in neotropical fish pacu, Piaractus mesopotamicus (Holmberg, 1887)

Copper sulfate is widely used in aquaculture. Exposure to this compound can be harmful to fish, resulting in oxidative metabolism alterations and gill tissue damage. Pacu, Piaractus mesopotamicus, (wt = 43.4 +/- A 3.35 g) were distributed in experimental tanks (n = 10; 180 l) and exposed for 48 h to control (without copper addition), 0.4Cu (0.4 mg l(-1)), 0CupH (without copper addition, pH = 5.0) and 0.4CupH (0.4 mg l(-1), pH = 5.0). In liver and red muscle, the superoxide dismutase (SOD) was responsive to the increases in the aquatic copper. The plasmatic intermediary metabolites and hematological variables in the fish of group 0.4Cu were similar to those of the control group. Conversely, the exposure to 0.4CupH caused an increase in the plasmatic lactate, number of red blood cells (RBC) and hemoglobin (Hb). Plasmatic copper concentration [Cu(p)] increased in group 0.4Cu and 0.4CupH, which is higher in group 0.4CupH, suggests an effect of water pH on the absorbed copper. Exposure to 0.4Cu and 0.4CupH resulted in a reduction in the Na(+)/K(+)-ATPase activity and an increase in metallothionein (MT) in the gills. Exposure to 0CupH caused a decrease in glucose and pyruvate concentrations and an increase in RBC, Hb, and the branchial Na(+)/K(+)-ATPase activity. These responses suggest that the fish triggered mechanisms to revert the blood acidosis, save energy and increase the oxygen uptake. MT was an effective biomarker, responding to copper in different pHs and dissolved oxygen. Combined-factors caused more significant disturbance in the biomarkers than single-factors.

Digestibility and performance of pacu (Piaractus mesopotamicus) juveniles - fed diets containing different protein, lipid and carbohydrate levels

Due to lack of information on the use of non-protein energy sources in diets for pacu (Piaractus mesopotamicus), a 2 x 2 x 3 factorial experiment was conducted to evaluate the performance and digestibility of 12 diets containing approximately two crude protein (CP; 220 and 250 g kg(-1)), two lipid (40 and 80 g kg(-1)) and three carbohydrate levels (410, 460 and 500 g kg(-1)). The pacu juveniles-fed diets containing 220 g kg(-1) CP did not respond (P > 0.05) to increased dietary lipid and carbohydrate levels, but the fish-fed diets containing 250 g kg(-1) CP showed a better feed conversion ratio. There were interactions in weight gain (WG), specific growth rate (SGR), crude protein intake (CPI) and feed conversion rate (FCR) dependent on dietary carbohydrate and lipid levels, showing positive effects of increasing carbohydrate levels only for fish-fed diets containing 80 g kg(-1) lipid level. However, when the diets contained 40 g kg(-1) lipid, the best energy productive value (EPV) results were obtained at 460 g kg(-1) carbohydrate. A higher usage of lipids (80 g kg(-1)) reduced CPI and was detrimental to protein [apparent digestibility coefficient (ADC)(CP)] and energy (ADC(GE)), but did not affect growth. The ADC(GE) improved proportionally as dietary carbohydrate levels increased (P < 0.05), increasing the concentration of digestible energy. In addition, the WG, CPI, ADC(GE) results showed best use of the energy from carbohydrates when dietary protein level was 250 g kg(-1) CP. The utilization of 250 g kg(-1) CP in feeds for juvenile pacu for optimal growth is suggested. Therefore, the optimum dietary lipid and carbohydrate levels depend on their combinations. It can be stated that pacu uses carbohydrates as effectively as lipids in the maximization of protein usage, as long as it is not lower than 250 g kg(-1) CP or approximately 230 g kg(-1) digestible protein.

Free- and peptide-based dietary arginine supplementation for the South American fish pacu (Piaractus mesopotamicus)

Arginine was hypothesized to be a model compound in the present study on molecular forms of indispensable amino acid (IAA) dietary supplementation. Juvenile South American pacu (Piaractus mesopotamicus) were fed diets containing arginine in a protein base (casein-wheat gluten or casein-gelatin), or the casein-wheat gluten base supplemented with dipeptide or free arginine at two levels (5 and 10 g kg(-1)). Growth and protein efficiency ratios were significantly affected by diets, but not by arginine molecular form. Three free dispensable amino acids (DAA) and four IAA in plasma were affected by diet, but plasma arginine concentrations did not differ. Plasma urea concentrations, being very low in the pacu, and hepatic arginase activities, were not affected by diet (P = 0.10-0.11), but together with plasma ornithine, mirrored the growth data. Molecular form of arginine supplementation, free or dipeptide, significantly changed several free IAA (Phe, Leu, Ile, His) and urea, with a higher mean plasma concentration in dipeptide fed fish. The dietary treatments, or molecular form of the arginine supplementation, did not change proximate composition, except that calcium levels decreased with higher dietary arginine supplementation level. The present study indicates that dipeptides can provide IAA to pacu, and that arginine supplemented in this form is utilized as efficiently as in free form.

Ocorrência e tratamento de monogenoides em alevinos de pampo (Trachinotus carolinus) cultivados experimentalmente na região norte do estado de São Paulo

This work had as objective tests therapeutic treatments seeking the monogenea eradication in fingerlings Florida Pompano (Trachinotus carolinus) servants in cage net in the area of Ubatuba, State of São Paulo. The fingerlings presented an accentuated weigh loss and strong discoloration and through observation of scraped of gills under light microscope were identified a high amount of monogenea. Three treatments were tested in form of baths: T1 (fresh water for 5 minutes); T2 (formalin: 1: 1.000 for 20 minutes) and T3: (formalin: 1:4.000 for 30 minutes). The treatments were appraised through scraped of gills, mounted among you laminate and laminulas and observed to the light microscope. It was observed that in the tested conditions all of the treatments were efficient in the elimination of the monogenea without presenting lethality to the fish. The treatment is recommended T I (take a bath in fresh water for 5 minutes) for the facility in the application and for the absence of use of chemical products.

Growth performance and energetic metabolism of pacu, Piaractus mesopotamicus (Holmberg, 1887), fed diets supplemented with ammonium metavanadate

Vanadium compounds mimic most of the metabolic effects of insulin, suggesting that it might be useful to improve utilization of dietary carbohydrate. This work evaluated the effect of dietary ammonium metavanadate (H(4)NO(3)V) on the growth performance and energy metabolism of pacu, an omnivorous South America characin. Two hundred and eighty-eight fish were distributed into four blocks according to the body weight (21.8 +/- 1.7, 28.5 +/- 2.0, 28.4 +/- 1.9, 35.7 +/- 1.9 g), stocked in 24 plastic tanks and fed twice daily with isonitrogenous and isoenergetic diets containing six levels of H(4)NO(3)V (0, 10, 50, 100, 300 and 1000 mg kg(-1)) for 60 days. Increasing levels of dietary ammonium metavanadate did not improve growth (P > 0.05), and the highest level of inclusion (1000 mg kg(-1)) reduced performance (P < 0.05). Blood glucose levels decreased (P < 0.05) in fish fed 300 and 1000 mg kg(-1) H(4)NO(3)V, but no differences were observed in other blood metabolites. A slight increase in muscle lipid content was observed in fish fed a diet containing 300 mg kg(-1) H(4)NO(3)V. Based on the results of this study, there is no benefit in supplementing pacu diets with metavanadate.

Leukocytes respiratory burst and lysozyme level in pacu (Piaractus mesopotamicus Holmberg, 1887)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dynamics of some limnological characteristics in pacu (Piaractus mesopotamicus) culture tanks as function of handling

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)