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Effects of copper in plasma, gills, liver and muscle of seabream (Sparus aurata, Linnaeus 1758) juveniles
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Advisor(s)
Abstract(s)
Em aquacultura, uma das principais restrições à produção é a ocorrência de
doenças em peixes. O sulfato de cobre é extensamente utilizado como tratamento contra
numerosos parasitas. Contudo, este composto é tóxico e fatal a altas concentrações.
Ainda que os efeitos toxicológicos do cobre em peixes estejam amplamente
documentados, existe uma elevada variabilidade de resultados apresentados. No
presente estudo, 121 juvenis de dourada (Sparus aurata) de 130.97 0.91 g (média
D.P.) foram mantidos a controlo (0 mg Cu/L), tratamento 1 (0.24 0.04 mg Cu/L),
tratamento 2 (0.66 0.12 mg Cu/L) e tratamento 3 (1.7 0.09 mg Cu/L) durante um
período de 26 dias seguido de um período de recuperação até ao dia 54. Os principais
resultados mostraram que a concentração de cobre no músculo e plasma não variou
entre os diferentes tratamentos. No entanto verificaram-se diferenças significativas a
nível do fígado. De um modo geral observaram-se diversos graus de alterações
histopatológicas. Estes serão possivelmente devidos aos diferentes mecanismos
fisiológicos existentes no peixe para diminuir os efeitos do cobre. Estes mecanismos
definirão a capacidade de adaptação às diferentes concentrações. Os peixes mantidos na
concentração mais elevada morreram antes do fim do ensaio, demonstrando que estas
concentrações são fatais para os juvenis de dourada em menos de 8 dias. Assim, os
resultados apontam que, independentemente da dose, a presença de cobre na água
produz alterações histopatológicas. Este estudo sugere também a existência de uma
recuperação tanto na concentração de cobre no fígado como ao nível dos tecidos das
brânquias e do fígado na dourada durante o período de recuperação. Em suma, o
tratamento de sulfato de cobre produz condições tóxicas para a dourada, levando a
alterações histológicas e acumulação de cobre. No entanto, estas alterações poderiam
ser restauradas com um tempo de recuperação apropriado.
In aquaculture, one of the major restrictions on production is due to disease. Copper sulphate is widely used as treatment, however, it is toxic and even fatal at high concentrations. Although toxicological effects of copper in fish are well documented, the variability of reported results is large. In the present study, 121 seabream (Sparus aurata) juveniles of 130.97 0.91 g (mean SD) were experimentally exposed to control group (0 mg Cu/L), treatment 1 (0.24 0.04 mg Cu/L), treatment 2 (0.66 0.12 mg Cu/L) and treatment 3 (1.7 0.09 mg Cu/L) during a period of 26 days followed with a recovery period to day 54. Principal results showed that while muscle and plasma Cu concentration did not vary among treatments, liver Cu concentration showed significant differences. In addition, diverse degrees of histopathological alterations were observed. This could be related to the treatment, and may be due to different physiological mechanism within the fish to mitigate copper effects. These mechanisms will define if a fish will or not adapt to different concentrations of copper. Fish held at the higher copper concentration died before the end of the experiment, proving that this concentration is fatal for seabream juveniles in less than 8 days. Results point to copper, independently of the dose, as inducer of histopathological alterations. This study also suggests histological and histochemical improvement in seabream during recovery period. In summary, copper sulphate treatment may be a toxicological condition for seabream, which produce histological alterations and copper accumulation. Nevertheless, these changes could be restored with a recovery period.
In aquaculture, one of the major restrictions on production is due to disease. Copper sulphate is widely used as treatment, however, it is toxic and even fatal at high concentrations. Although toxicological effects of copper in fish are well documented, the variability of reported results is large. In the present study, 121 seabream (Sparus aurata) juveniles of 130.97 0.91 g (mean SD) were experimentally exposed to control group (0 mg Cu/L), treatment 1 (0.24 0.04 mg Cu/L), treatment 2 (0.66 0.12 mg Cu/L) and treatment 3 (1.7 0.09 mg Cu/L) during a period of 26 days followed with a recovery period to day 54. Principal results showed that while muscle and plasma Cu concentration did not vary among treatments, liver Cu concentration showed significant differences. In addition, diverse degrees of histopathological alterations were observed. This could be related to the treatment, and may be due to different physiological mechanism within the fish to mitigate copper effects. These mechanisms will define if a fish will or not adapt to different concentrations of copper. Fish held at the higher copper concentration died before the end of the experiment, proving that this concentration is fatal for seabream juveniles in less than 8 days. Results point to copper, independently of the dose, as inducer of histopathological alterations. This study also suggests histological and histochemical improvement in seabream during recovery period. In summary, copper sulphate treatment may be a toxicological condition for seabream, which produce histological alterations and copper accumulation. Nevertheless, these changes could be restored with a recovery period.
Description
Dissertação de Mestrado, Aquacultura e Pescas, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2006
Keywords
Aquacultura Dourada Cobre Alterações histopatológicas Acumulação