58 resultados para Giant river prawn
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The aim of this study was to evaluate the effect of stocking ponds using graded and ungraded juveniles and performing drained and combined harvesting on the production of M. amazonicum. A randomized completed-blocks design with 4 treatments (farming strategies) and 3 replicates was used. Treatments were: Upper size-graded juveniles, Lower size-graded juveniles, Ungraded juveniles, all with total drained harvesting, and Combined Harvesting (ungraded juveniles). Twelve earthen ponds were stocked at 40 juveniles.m -2, according to the treatment. After 3.5 months prawns were completely harvested. Lower size-graded prawns showed smaller average weight (3.37 ± 0.25 g) than upper size-graded (4.03 ± 0.40 g) and ungraded ones (3.80 ± 0.16 g). Survival percentage varied from 68 ± 9 to 76 ± 10, productivity was slightly higher than 1,000 kg.ha -1 and apparent feed conversion rate varied from 3.0 ± 0.7 to 3.7 ± 1.3. These parameters did not differ among the farming strategies. The best strategy for short term grow-out M. amazonicum in earthen ponds is stocking ungraded juveniles and performing total harvesting by draining ponds at the end of rearing cycle. Grading juveniles before stocking and selective-harvesting managements are not advantageous because they increase costs and do not improve any production parameter.
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Studies to determine suitable levels of intensification are essential for developing sustainable aquaculture. The objective of this study was to evaluate the quality of effluents discharged from ponds stocked with 10 (D10), 20 (D20), 40 (D40), and 80 (D80) postlarvae of Macrobrachium amazonicum/m2. Intake and effluent water samples were taken throughout a 5.5-mo grow-out cycle. In that study, twelve 0.01-ha earthen ponds were stocked postlarvae with 0.01g. Average water exchange rate was 15%/d; water was discharged from the bottom of the ponds. Prawns were fed a commercial feed with 38% crude protein according to their biomass (3-10%) and the concentration of dissolved oxygen (DO). In our research, temperature, turbidity, total suspended solids, conductivity, DO, pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), N-ammonia, N-nitrite, N-nitrate, N-Kjeldahl nitrogen, total phosphorus, and soluble orthophosphate were measured every 15d throughout the experiment in the early morning (0630 to 0730h). Turbidity was lower in D10 than in D20 and D40 and total phosphorus was higher in D80 than in D10 and D20. An analysis of principal components comparing treatments and intake water showed three groups: intake, D10 and a cluster of D20, D40, and D80. On the basis of the water characteristics found in our study it appears that the farming of M. amazonicum is likely to have a low environmental impact, at least up to a stocking density of 80prawns/m2. © by the World Aquaculture Society 2013.
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The stimulation by Mg2+, Na+, K+, NH 4 +, and ATP of (Na+, K+)-ATPase activity in a gill microsomal fraction from the freshwater prawn Macrobrachium rosenbergii was examined. Immunofluorescence labeling revealed that the (Na +, K+)-ATPase α-subunit is distributed predominantly within the intralamellar septum, while Western blotting revealed a single α-subunit isoform of about 108 kDa M r. Under saturating Mg2+, Na+, and K+ concentrations, the enzyme hydrolyzed ATP, obeying cooperative kinetics with V M = 115.0 ± 2.3 U mg-1, K 0.5 = 0.10 ± 0.01 mmol L-1. Stimulation by Na+ (V M = 110.0 ± 3.3 U mg-1, K 0.5 = 1.30 ± 0.03 mmol L -1), Mg2+ (V M = 115.0 ± 4.6 U mg -1, K 0.5 = 0.96 ± 0.03 mmol L-1), NH4 + (V M = 141.0 ± 5.6 U mg -1, K 0.5 = 1.90 ± 0.04 mmol L-1), and K+ (V M = 120.0 ± 2.4 U mg-1, K M = 2.74 ± 0.08 mmol L-1) followed single saturation curves and, except for K+, exhibited site-site interaction kinetics. Ouabain inhibited ATPase activity by around 73 % with K I = 12.4 ± 1.3 mol L-1. Complementary inhibition studies suggest the presence of F0F1-, Na+-, or K +-ATPases, but not V(H+)- or Ca2+-ATPases, in the gill microsomal preparation. K+ and NH4 + synergistically stimulated enzyme activity (≈25 %), suggesting that these ions bind to different sites on the molecule. We propose a mechanism for the stimulation by both NH4 +, and K+ of the gill enzyme. © 2013 Springer Science+Business Media New York.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The Amazon River prawn Macrobrachium amazonicum is endemic to tropical South America and is being intensively exploited by artisanal fisheries in Brazil. Limited information is available about the nutritional requirements of M. amazonicum, although the production of this species is now technically feasible. The digestive process in this species is still unclear and investigation into the digestive cells of its hepatopancreatic epithelium is required. Thus, the hepatopancreas from 15 specimens were fixed in Karnovsky Solution and processed for Transmission Electron Microscopy. Our results indicate that E cells are located at the distal portion of the hepatopancreatic tubule and are involved in mitotic activity. The cylindrical R cells are sparse and are only found in the proximal portion of the hepatopancreatic tubule. According to its ultrastructural characteristics, this cell is involved in pinocytosis. M cells are generally found near the R cells. The F cells are scattered throughout the length of the hepatopancreatic tubules, and B cells are observed mainly in the proximal and middle regions. F cells and B cells are likely related to, respectively, the synthesis of enzymes and the intracelular digestion. R- and M cells are probably related to material storage. Thus, these findings provide basic information on the cell types that perform protein digestion in M. amazonicum, and will be useful in further nutritional research. The identification and characterization of digestive cells is an important step towards understanding the digestive mechanisms.