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

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

Glyphosate on digestive enzymes activity in piava (Leporinus obtusidens)

The effects of glyphosate, a nonselective herbicide (1.0 or 5.0mg L-1) on digestive enzymes activity (stomach and intestine) were evaluated in juveniles of piava (Leporinus obtusidens) after 90 days of exposure. The activity of acid protease, trypsin, chymotrypsin and amylase increased with the increase of glyphosate concentration. These results indicate that glyphosate affects digestive enzyme activities in this species, and may be an indicator of poor nutrient availability when fish survive in herbicide-contaminated water

Supplementation with microencapsulated lemongrass essential oil improves protein deposition and carcass yield in silver catfish (Rhamdia quelen)

<div><p>ABSTRACT. The aim of this study was to investigate the effect of dietary supplementation with Cymbopogon flexuosus essential oil (EO) on productive performance, metabolic parameters and body and fillet composition of adult silver catfish, Rhamdia quelen. Total length, condition factor, weight gain, specific growth rate, hepatosomatic index, visceral fat content and fillet composition were not affected by EO supplementation. Plasma total protein, globulin and triglycerides were reduced by EO supplementation. Supplementation with 1 mL EO kg-1 diet increased carcass yield and protein deposition in the carcass, while reducing gonadosomatic index and fat deposition in the carcass when compared to control group. In addition, 1 mL EO kg-1 diet also improved feed intake when compared to 3 mL EO kg-1 diet. Our results suggest that EO up to 1 mL kg-1 diet can be used in fish feed to improve protein deposition and carcass yield of silver catfish.</p></div

Anesthetic activity and bio-guided fractionation of the essential oil of Aloysia gratissima (Gillies & Hook.) Tronc. in silver catfish Rhamdia quelen

This work aimed to determine the efficacy of the essential oil of A. gratissima as anesthetic for silver catfish, and to perform the bio-guided fractionation of essential oil aiming to isolate compounds responsible for the noted effects. Fish were submitted to anesthesia bath with essential oil, its fractions and isolated compounds to determine time of anesthetic induction and recovery. Eugenol (50 mg L-1) was used as positive control. Essential oil of A. gratissima was effective as an anesthetic at concentrations of 300 to 900 mg L-1. Fish presented involuntary muscle contractions during induction and recovery. The bio-guided fractionation of essential oil furnishedE-(-)-pinocamphone, (-)-caryophyllene oxide, (-)-guaiol and (+)-spathulenol. E-(-)-pinocamphone caused the same side effects observed for essential oil. (-)-Caryophyllene oxide, (-)-guaiol and (+)-spathulenol showed only sedative effects at proportional concentrations to those of the constituents in essential oil. (+)-Spathulenol (51.2 mg L-1) promoted deep anesthesia without side effects. A higher concentration of (+)-spathulenol, and lower or absent amounts ofE-(-)-pinocamphone could contribute to increase the activity and safety of the essential oil of A. gratissima. (+)-Spathulenol showed potent sedative and anesthetic activities in silver catfish, and could be considered as a viable compound for the development of a new anesthetic

Different feeding habits influence the activity of digestive enzymes in freshwater fish

ABSTRACT: The aim of this study was to verify the activity of some digestive enzymes in four fish species with different feeding habits. Knowledge of these enzymatic activities can help us to understand the species' digestive processes. The species chosen for this study were Ctenopharyngodon idella (herbivore), Rhamdia quelen (omnivore), Leporinus obtusidens (omnivore) and Hoplias malabaricus (carnivore). The digestive tract of these species was divided into four portions to estimate enzymatic activity: stomach, anterior, mid and posterior intestine. Ctenopharyngodon idella had the highest amylase and maltase activities in all portions of the gut, followed by L. obtusidens . The highest trypsin activity was observed in all gut portions of H. malabaricus, followed by the mid intestine of L. obtusidens and the anterior intestine of C. idella . The highest chymotrypsin activity was found in all portions of C. idella followed by the anterior intestines of R. quelen, L. obtusidens and H. malabaricus . In the stomach, acid protease activity was significantly lower in R. quelen and L. obtusidens compared to H. malabaricus. Ctenopharyngodon idella showed high activity of enzymes that hydrolyze carbohydrates, represented in this study by amylase and maltase and H. malabaricus showed higher protease activity and low amylase activity