Respostas fisiológicas do matrinxã Brycon amazonicus após mudança de ambientes com diferentes concentrações de sais de cálcio e de sódio
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Data
2008-02-22
Autores
Bendhack, Fabiano [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Na aqüicultura, os peixes são freqüentemente expostos a agentes estressores como os choques osmóticos presentes principalmente nas práticas de transferência. O presente estudo analisou as respostas fisiológicas do matrinxã Brycon amazonicus à transferência para ambientes com diferentes concentrações de sais dissolvidos (cloreto de cálcio e cloreto de sódio). No experimento com cloreto de cálcio, num primeiro ensaio, os peixes foram aclimatados em caixas de 500 L com água sem adição de sais e após 48 horas de jejum foram transferidos para unidades individuais contendo cloreto de cálcio (0, 150, 300 e 600 mg L-1). Em outro ensaio, os peixes foram aclimatados por 12 horas nas mesmas concentrações de CaCl2 e transferidos para as unidades sem adição do sal. As amostragens foram realizadas antes, 1, 3, 6 e 12 horas após a transferência. Verificou-se os níveis de glicose plasmática, íons e parâmetros hematológicos, além da taxa de excreção de amônia e atividade da enzima Na+ K+ ATPase nas brânquias. Os peixes transferidos para água com CaCl2 apresentaram as principais alterações no sódio sérico depois de uma hora. No outro experimento, os peixes foram submetidos aos mesmos procedimentos, porém com adição de NaCl (0, 3, 6 e 9 g L-1). Neste caso, os peixes apresentaram menor resposta ao estresse de acordo com a glicemia, porém os níveis séricos de sódio se elevaram nos peixes transferidos para 9 g L-1. Quando transferidos para ambiente com cálcio, apresentaram alterações moderadas, já quando submetidos ao choque da transferência para água sem sais, as respostas foram mais homogêneas sugerindo maior facilidade na adaptação. No caso do NaCl é possível sugerir que este sal possui papel importante na mitigação do estresse, entretanto, a concentração deste sal pode interferir no benefício.
In aquaculture, fish are frequently exposed to stressors agents such as shocks osmotic present mainly in the practices of transfer. This study examined the physiological responses of matrinxã Brycon amazonicus transferred to environments with different concentrations of dissolved salts (calcium chloride and sodium chloride). In the experiment with calcium chloride, in a first assay, the fish were adapted in 1000 L aquaria, without salts, after 48 hours of fasting were transferred to individual units containing calcium chloride (0,150, 300 and 600 mg L-1). In another assay, the fish were adapted for 12 hours in the same concentrations of CaCl2 and transferred to the individual units without the addition of salts. Samples were taken before, 1, 3, 6 and 12 hours after the transfer. Plasma glucose, ionic and haematological parameters, the rate of excretion of ammonia and enzyme activity of Na+ K+ ATPase in the gills were checked. The fish transferred from water without salts to water with CaCl2 showed the main changes in serum sodium one hour after the management. After adjusting the water with calcium, the enzyme activity of the Na+ K+ ATPase proved to be greater in the most concentrated, but equally the values of the control group after the transfer. In another experiment, the fish underwent the same procedures, but with the replacement of the calcium chloride sodium chloride (0, 3, 6 and 9 g L-1). In this case, the fish had lower response to stress, according to the blood glucose, but the serum levels of sodium are raised in fish transferred to 9 g L-1. When transferred to environment with calcium, showed moderate changes, as when subjected to shock transfer to the water without salt, the answers were more homogeneous suggesting greater ease in adapting. In the case of NaCl is possible to suggest that this salt has important role in mitigating the stress, however, concentration this salt may interfere on benefit.
In aquaculture, fish are frequently exposed to stressors agents such as shocks osmotic present mainly in the practices of transfer. This study examined the physiological responses of matrinxã Brycon amazonicus transferred to environments with different concentrations of dissolved salts (calcium chloride and sodium chloride). In the experiment with calcium chloride, in a first assay, the fish were adapted in 1000 L aquaria, without salts, after 48 hours of fasting were transferred to individual units containing calcium chloride (0,150, 300 and 600 mg L-1). In another assay, the fish were adapted for 12 hours in the same concentrations of CaCl2 and transferred to the individual units without the addition of salts. Samples were taken before, 1, 3, 6 and 12 hours after the transfer. Plasma glucose, ionic and haematological parameters, the rate of excretion of ammonia and enzyme activity of Na+ K+ ATPase in the gills were checked. The fish transferred from water without salts to water with CaCl2 showed the main changes in serum sodium one hour after the management. After adjusting the water with calcium, the enzyme activity of the Na+ K+ ATPase proved to be greater in the most concentrated, but equally the values of the control group after the transfer. In another experiment, the fish underwent the same procedures, but with the replacement of the calcium chloride sodium chloride (0, 3, 6 and 9 g L-1). In this case, the fish had lower response to stress, according to the blood glucose, but the serum levels of sodium are raised in fish transferred to 9 g L-1. When transferred to environment with calcium, showed moderate changes, as when subjected to shock transfer to the water without salt, the answers were more homogeneous suggesting greater ease in adapting. In the case of NaCl is possible to suggest that this salt has important role in mitigating the stress, however, concentration this salt may interfere on benefit.
Descrição
Palavras-chave
Peixe, Regulação osmotica, Estresse
Como citar
BENDHACK, Fabiano. Respostas fisiológicas do matrinxã Brycon amazonicus após mudança de ambientes com diferentes concentrações de sais de cálcio e de sódio. 2008. vi, 84 f. Tese (doutorado) - Universidade Estadual Paulista, Centro de Aqüicultura, 2008.