Recuperação de alevinos de pacu (Piaractus mesopotamicus) e tilápia (Oreochromis niloticus) sobreviventes à intoxicação aguda por fipronil
Arquivos
Data
2018-05-25
Autores
Ignácio, Naiara Fernanda [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Objetivou-se avaliar a capacidade de recuperação de alevinos de peixes das espécies de cativeiro pacu (Piaractus mesopotamicus) e tilápia (Oreochromis niloticus) após a intoxicação aguda com fipronil. A capacidade de recuperação foi avaliada nos peixes sobreviventes as concentrações de fipronil (Regent® 800WG) (0,56; 0,59; 0,61 e 0,64 mg.L-1 para o pacu; e 0,9; 0,11; 0,15 e 0,20 mg.L-1 para a tilápia) que causaram aproximadamente 10, 30, 50 e 70% de mortalidade após 24 horas de exposição aguda. Os peixes sobreviventes foram transferidos para água limpa. As avaliações foram realizadas no dia da transferência para a água limpa, e aos 15 e 30 dias de recuperação. Foram avaliadas as lesões em tecidos de brânquias, fígado e rins, e a atividade da enzima acetilcolinesterase (AChE) no cérebro e no músculo. Os sinais observados foram natação errática, espasmos musculares e mudança de coloração. Após 24 horas de exposição aguda, o fipronil, nas concentrações avaliadas, causou lesões estruturais nas brânquias, fígado e rins dos peixes, entre 70 e 73% de inibição da atividade da AChE no cérebro e entre 20 e 35% da AChE no músculo. Os peixes se recuperaram completamente dos sinais de intoxicação no terceiro dia. Aos 30 dias de recuperação, os peixes das duas espécies se recuperaram das lesões nos tecidos das brânquias, fígado e rins causadas pelo fipronil em concentração nas águas de até 0,61 mg.L-1 para o pacu, que causa até 54,2 % mortalidades; e de até 0,15 mg.L-1 para a tilápia, que causa até 46,7% de mortalidade. Em concentrações superiores a estas, o fipronil causou maior mortalidade e os peixes não se recuperaram totalmente. Os 30 dias em água limpa não são suficientes para a recuperação total da atividade da AChE, o que não altera o peso corpóreo. Portanto, os limites de aceitabilidade de inibição da atividade da AChE após 24 horas de exposição aguda ao fipronil é de 70% no cérebro dos peixes de ambas as espécies, 30% no músculo de pacu e 22% no da tilápia. As concentrações de fipronil não alteram as variáveis de qualidade de água.
The aim of this study was to evaluate the recovery capacity of juvenile fishes of the species pacu (Piaractus mesopotamicus) and tilapia (Oreochromis niloticus) after acute intoxication with fipronil. Recovery capacity was evaluated in fishes survivors from fipronil concentrations (Regent® 800WG) (0,56; 0,59; 0,61 e 0,64 mg.L-1 para for pacu; e 0,9; 0,11; 0,15 e 0,20 mg.L-1 for tilápia) in water that caused about 10, 30, 50 and 70% of mortality after 24 hours of acute exposure. The survivors were transferred to clean water. The evaluations were done on the day of transfer to clean water, and at 15 and 30 days of recovering. Damages were evaluated in gills, liver and kidneys tissues and the enzyme acetylcholinesterase (AChE) activity in the brain and muscle. The signs observed were erratic swimming, muscle spasms and color change. After 24 hours of acute exposure, fipronil at the tested concentrations causes histological damages in the gills, liver and kidneys of the fishes, 70 to 73% inhibition of AChE activity in the brain and between 20 and 35% in AChE in the muscle. The fishes recover completely from the intoxication signs on the third day. At 30 days of recovering, fishes from both species recovered from the damage in gills, liver and kidneys caused by fipronil at concentrations up to 0.61 mg.L-1 for pacu, which cause up to 54.2% of mortality; and up to 0.15 mg.L-1 for tilapia, which cause up to 46.7% of mortality. In higher concentrations than these, fipronil causes higher mortalities and the fishes do not recover fully. The 30 days in clean water are not enough for the total recovery of AChE activity, which does not change the body weight. Therefore, the acceptability of inhibition limit of AChE activity after 24 hours of acute fipronil exposure is 70% in fish brain of both species, 30% in pacu muscle and 22% in tilapia muscle. Fipronil concentrations do not alter the water quality variables.
The aim of this study was to evaluate the recovery capacity of juvenile fishes of the species pacu (Piaractus mesopotamicus) and tilapia (Oreochromis niloticus) after acute intoxication with fipronil. Recovery capacity was evaluated in fishes survivors from fipronil concentrations (Regent® 800WG) (0,56; 0,59; 0,61 e 0,64 mg.L-1 para for pacu; e 0,9; 0,11; 0,15 e 0,20 mg.L-1 for tilápia) in water that caused about 10, 30, 50 and 70% of mortality after 24 hours of acute exposure. The survivors were transferred to clean water. The evaluations were done on the day of transfer to clean water, and at 15 and 30 days of recovering. Damages were evaluated in gills, liver and kidneys tissues and the enzyme acetylcholinesterase (AChE) activity in the brain and muscle. The signs observed were erratic swimming, muscle spasms and color change. After 24 hours of acute exposure, fipronil at the tested concentrations causes histological damages in the gills, liver and kidneys of the fishes, 70 to 73% inhibition of AChE activity in the brain and between 20 and 35% in AChE in the muscle. The fishes recover completely from the intoxication signs on the third day. At 30 days of recovering, fishes from both species recovered from the damage in gills, liver and kidneys caused by fipronil at concentrations up to 0.61 mg.L-1 for pacu, which cause up to 54.2% of mortality; and up to 0.15 mg.L-1 for tilapia, which cause up to 46.7% of mortality. In higher concentrations than these, fipronil causes higher mortalities and the fishes do not recover fully. The 30 days in clean water are not enough for the total recovery of AChE activity, which does not change the body weight. Therefore, the acceptability of inhibition limit of AChE activity after 24 hours of acute fipronil exposure is 70% in fish brain of both species, 30% in pacu muscle and 22% in tilapia muscle. Fipronil concentrations do not alter the water quality variables.
Descrição
Palavras-chave
Fipronil, Contaminação, Histologia, Acetilcolinesterase, Biomarcadores, Contamination, Histology, Acetylcholinesterase, Biomarkers