Acetylcholinesterase activity in the brain and muscle of Cyprinus carpio and Aristichthys nobilis exposed to azimsulfuron and metsulfuron-methyl

Alevinos de carpa húngara (Cyprinus carpio) e carpa cabeça grande (Aristichthys nobilis) foram expostas a azimsulfuron e metsulfuron-metil (50, 100 and 200 mg L-1), herbicidas utilizados em lavouras de arroz no Sul do Brasil. Os peixes sobreviveram a todas as concentrações testadas de ambos os herbicidas e mostraram comportamento alimentar e natatório normal. Azimsulfuron inibiu significativamente a enzima acetilcolinesterase (AChE) em cérebro e músculo de ambas as espécies e metsulfuron-metil aumentou a atividade da AChE no cérebro e a inibiu em músculo. O presente estudo mostrou que azimsulfuron e metsulfuron-metil não afetam os comportamentos (alimentar e natatório) de C. carpio e A. nobilis, mas inibiram a atividade da AChE em tecido cerebral e muscular dessas espécies.Common carp (Cyprinus carpio) and bighead carp (Aristichthys nobilis) were exposed to azimsulfuron and metsulfuron-methyl (50, 100 and 200 mg L-1). These herbicides are used in rice crop in Southern Brazil. Fishes survived to all tested concentrations of both herbicides and showed normal feeding and swimming behavior. Azimsulfuron inhibits significantly acetylcholinesterase (AChE) in brain and muscle of both species, and metsulfuron-methyl increase AChE activity in brain and inhibits in muscle. The present study showed that azimsulfuron and metsulfuron-methyl did not affect C. carpio and A. nobilis behaviors (feeding and swimming), but inhibited AChE activity in brain and muscle tissues of these species

EFEITOS DO CARBOFURANO, METSULFUROM-METÍLICO E AZINSULFUROM NA SOBREVIVÊNCIA DE CARPAS E PRODUÇÃO DE ARROZ E PEIXES EM RIZIPISCICULTURA

This study was carried out to evaluate the fingerlings carps survival exposure to carbofuran, metsulfuron-methyl and azimsulfuron in rice-fish culture, as well as irrigate rice and fish production. Common, grass and bighead fingerlings carps were exposed to carbofuran, metsulfuron-methyl and azimsulfuron agrochemicals in pre-germinated rice production system with continual flooding water management during 2003/04 and 2004/05 growing season. Randomized complete block design with eight treatments and four repetitions, associating carps under the presence and absent of agrochemicals. Seven days after agrochemicals application, fingerlings carps were put in the area and it was verified that agrochemicals did not affect these survival. Due to use of continual flooding water management system, the rice yield grain is not affected by agrochemicals utilization.Este trabalho foi conduzido com o objetivo de avaliar a sobrevivência de alevinos de carpas expostas a carbofuran, metsulfuron-metílico e azimsulfuron em rizipiscicultura, bem como a produção de arroz irrigado e peixes. Foram utilizados alevinos de carpas húngara, capim e cabeça grande expostos aos agroquímicos em sistema pré-germinado de produção de arroz com manejo adequado de lâmina de água contínua durante os anos agrícolas de 2003/04 e 2004/05. O delineamento experimental foi de blocos ao acaso com oito tratamentos e quatro repetições, associando carpas sob a presença ou ausência de agroquímicos. Sete dias após a aplicação dos agroquímicos os alevinos de carpas foram colocados na área e foi verificado que os agroquímicos não afetam a sobrevivência destes. Devido a utilização de lâmina contínua de água no sistema a produção de grãos de arroz não foi afetada pela utilização de agroquímicos

Acetylcholinesterase enzyme activity in carp brain and muscle after acute exposure to diafuran

Sublethal adverse effects may result from exposure of aquatic organisms to insecticides at environmentally relevant concentrations. Fingerlings of the common carp (Cyprinus carpio, Linnaeus, 1758), grass carp (Ctenopharyngodon idella, Valenciennes, 1844), and bighead carp (Aristichthys nobilis, Richardson, 1845) were exposed to diafuran, an insecticide widely used during rice cultivation in Southern Brazil. The aim of this study was to verify the relationship between the lethal concentration (LC50) of diafuran and the acetylcholinesterase (AChE) activity in brain and muscle tissues of these species as a possible early biomarker of exposure to this insecticide. LC50 was determined for fish exposed to diafuran concentrations during 96 h (short term): common carp: control, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mg L-1; grass carp: control, 1.0, 2.0, 3.0 and 3.5 mg L-1 and, bighead carp: control, 0.5, 1.0, 1.5, 2.0, 3.0 and 4.0 mg L-1, as well as the determination of AChE at concentrations near LC50 for these species. LC50 values (nominal concentrations) were 1.81 mg L-1 for the common carp, 2.71 mg L-1 for the grass carp and, 2.37 mg L-1 for the bighead carp. All carps exposed to diafuran were lethargic (lower concentrations) or immobile. Diafuran inhibited the acetylcholinesterase activity in brain (~38%) and muscle (~50%) of all species. Muscle of bighead carp under control treatment showed higher specific AChE activity than brain (14.44 against 5.94 µmol min-1 g protein-1, respectively). Concentrations of diafuran used for rice cropping may affect Cyprinus carpio, Ctenopharyngodon idella and Aristichthys nobilis behaviors and the AChE activities in brain and muscle of these species may be an early biomarker of toxicity of this insecticide.Exposição a inseticidas em concentrações elevadas no ambiente podem ocasionar efeitos adversos subletais em organismos aquáticos. Alevinos de carpa húngara (Cyprinus carpio, Linnaeus, 1758), carpa capim (Ctenopharyngodon idella, Valenciennes, 1844) e carpa cabeça grande (Aristichthys nobilis, Richardson, 1845) foram expostos ao diafuran, um inseticida utilizado na cultura do arroz no sul do Brasil. O objetivo deste estudo foi verificar a relação entre concentração letal mediana (CL50) do diafuran e a atividade da enzima acetilcolinesterase (AChE) em cérebro e músculo dessas espécies, como um possível biomarcador inicial da exposição a este inseticida. A CL50 foi determinada com peixes expostos a concentrações de diafuran em 96 h: carpa húngara: controle; 0,5; 1,0; 1,5; 2,0; 2,5 e 3,0 mg L-1; carpa capim: controle; 1,0; 2,0; 3,0 e 3,5 mg L-1 e carpa cabeça grande: controle; 0,5; 1,0; 1,5; 2,0; 3,0 e 4,0 mg L-1, bem como a determinação da AChE em concentrações próximas da CL50 para essas espécies. Valores de CL50 (concentrações nominais) foram de 1,81 mg L-1 para carpa húngara, 2,71 mg L-1 para carpa capim e 2,37 mg L-1 para carpa cabeça grande. Todas as carpas expostas ao diafuran estavam letárgicas (menores concentrações) ou imóveis. Diafuran inibiu significativamente a atividade da AChE em cérebro (~38 %) e músculo (~50 %) de todas as espécies estudadas. Atividade da AChE em músculo para carpa cabeça grande foi mais alta que cérebro (14,44 contra 5,94 µmol min-1 g proteína-1, respectivamente). Este estudo demonstrou que concentrações de diafuran utilizadas na cultura do arroz podem afetar o comportamento de Cyprinus carpio, Ctenopharyngodon idella e Aristichthys nobilis, e a atividade da acetilcolinesterase cerebral e muscular pode ser um biomarcador inicial de toxicidade deste inseticida

Growth and survival of silver catfish larvae, Rhamdia quelen (Heptapteridae), at different calcium and magnesium concentrations

Since the relative ratios of Ca2+ and Mg2+ can vary greatly from one water body to another, and lime used for the increase of water hardness or pH can have different ratios of Ca2+ and Mg2+ in its composition, the objective of this study was to analyze the growth and survival of silver catfish, Rhamdia quelen, larvae at different calcium and magnesium concentrations. After fertilization, eggs were randomly divided into 4 treatments (three replicates per treatment) with different concentrations of Ca2+ and Mg2+ at hardness values of 70 mg.L-1 CaCO3 (mg.L-1 : 5.2 Ca2+ and 14.12 Mg2+; 13.11 Ca2+ and 7.11 Mg2+; 20.26 Ca2+ and 2.86 Mg2+; 24.95 Ca2+ and 0.95 Mg2+) and 150 mg.L-1 CaCO3 (mg.L-1 : 5.2 Ca2+ and 32.70 Mg2+; 28.63 Ca2+ and 16.44 Mg2+; 44.68 Ca2+and 6.44 Mg2+; 62.78 Ca2+ and 0.95 Mg2+). There was also another group exposed to water hardness of 20 mg.L-1 CaCO3 (Ca2+ 5.2 mg.L-1 and Mg2+ 0.95 mg.L-1) at both experiments. The post-hatch larvae were transferred to continuously aerated 40 L polyethylene aquaria (400 larvae/tank) containing the same water as used for incubation. Samples of larvae were collected on days 0, 7, 14, and 21, and the length, weight, and specific growth rate were determined for each collection. Survival and biomass were calculated on day 21. At water hardness of 70 mg.L-1 CaCO3, the best survival and growth of silver catfish larvae was observed at water with 20.26 mg.L-1 Ca2+ and 2.89 mg.L-1 Mg2+, with similar results to the group exposed to water hardness of 20 mg.L-1 CaCO3. However, compared to the group exposed to water hardness of 20 mg.L-1 CaCO3, survival and growth were lower at 150 mg.L-1 CaCO3. Therefore, a hardness range of 20 to 70 mg.L-1 CaCO3 is recommended for silver catfish larviculture, but with 20.26 mg.L-1 Ca2+ and 2.89 mg.L-1 Mg2+ at 70 mg.L-1 CaCO3. Water hardness of 150 mg.L-1 CaCO3 is not recommended for this species

Ionic levels of the gallbladder bile of some teleosts from the Rio Negro, Amazon

The ionic levels of the gallbladder bile of 23 species of teleosts from the Rio Negro, Amazon, were analysed. Ionic levels of the gallbladder bile were variable according to the species and could not be related to the feeding habit or fullness of the gut. © 2004 The Fisheries Society of the British Isles