RESUMO
Major tailings dam failures have occurred recently around the world and resulted in severe environmental impacts, such as metal contamination. Manganese is a metal highly associated with mining activities, largely detected in mining dam collapses. This metal is considered necessary for different organisms, but it can be toxic and cause oxidative stress and genetic damage in fishes. In this study, we investigated the toxic effects of manganese on Astyanax lacustris, by exposing the fish individually to different concentrations of this metal (2.11, 5.00, and 10.43 mg/L) for 96 h. To assess the effects of manganese, we used biochemical biomarkers (glutathione S-transferase, catalase, and acetylcholinesterase enzyme activity) and the manganese bioaccumulation in different tissues (liver and gills). The obtained data showed that only at concentrations of 5.00 mg/L and 10.43 mg/L the activity of glutathione S-transferase differed significantly. Additionally, the acetylcholinesterase activity in the brain tissue was inhibited. The highest level of manganese bioaccumulation was observed in the liver and branchial tissue. Overall, we concluded that high concentrations of manganese may cause physiological changes in Astyanax lacustris.
Assuntos
Bioacumulação , Characidae , Manganês , Poluentes Químicos da Água , Animais , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/metabolismo , Manganês/toxicidade , Manganês/metabolismo , Characidae/metabolismo , Characidae/fisiologia , Acetilcolinesterase/metabolismo , Fígado/metabolismo , Fígado/efeitos dos fármacos , Glutationa Transferase/metabolismo , Brânquias/metabolismo , Biomarcadores/metabolismoRESUMO
Piaractus mesopotamicus, is a fish usually farmed in semi-intensive systems with access to natural food and supplementary feed. This study evaluates effects of feed allowance on the productive performance, carbon turnover and proportions of nutrient (carbon) contribution of feed and natural food for the growth of pacu. Juvenile fish were stocked in fiberglass tanks and fed to 100, 75, 50, 25, 0% apparent satiety (ApS), with a practical, extruded (C4 photosynthetic pathway) feed in a randomized design trial (n=3); plankton production for simulated semi-intensive farming system condition was induced by chemical fertilization. A control treatment was set up in tanks devoid of natural food. Data on muscle stable carbon isotope ratios were used to study carbon turnover using a relative growth-based model. Low variation of the δ13C impaired fitting a turnover model curve for the 0 and 25 % ApS treatments. Fish of the 100% and 75% ApS treatments reached circa 95% and 82.85% of the carbon turnover, respectively. Extruded feed was the main nutrient source for the growth of pacu in the semi-intensive, simulated farming condition. The current study contributes to the knowledge of the relationship between feeding rates and carbon turnover rates in the pacu muscle.
Assuntos
Ração Animal , Isótopos de Carbono , Carbono , Animais , Ração Animal/análise , Carbono/metabolismo , Carbono/análise , Isótopos de Carbono/análise , Characidae/fisiologia , Characidae/crescimento & desenvolvimento , Characidae/metabolismo , Aquicultura/métodos , Fenômenos Fisiológicos da Nutrição AnimalRESUMO
In this study, we examine markers of oxidative stress in the tetra Hyphessobrycon luetkenii collected from two locations in the copper contaminated João Dias creek (southern Brazil). Also, specimens were translocated from a clean reference section of the creek to a polluted stretch and vice-versa. Fish were held at in submerged cages for 96 h and then sacrificed. Nuclear abnormalities in erythrocytes and total antioxidant capacity, lipid peroxidation and protein carbonylation in gills, brain, liver and muscle displayed similar trends in both groups. Lipid peroxidation increased in all tissues of individuals translocated to the polluted site but only in liver and muscle of those translocated to the reference site. Increased protein carbonylation was also observed in gills of individuals translocated to the reference location. These results suggest similar oxidative stress among fish from the reference and polluted locations and that long-term metals exposure may require adaptations toward oxidative stress responses.
Assuntos
Characidae , Poluentes Químicos da Água , Animais , Cobre/toxicidade , Cobre/metabolismo , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/metabolismo , Estresse Oxidativo , Characidae/metabolismo , Água Doce , Mineração , Brânquias/metabolismo , Peroxidação de Lipídeos , Fígado/metabolismoRESUMO
The present study aimed to evaluate the toxicity of Mn (6.65 mg/L) at different exposure times (96 h, 7, 14, and 21 days) and evaluate its possible toxic effects on the fish Astyanax lacustris through multi-biomarkers and the maximum critical temperature (CT Max). The results show an increase in the Mn accumulation (liver and gills) with increasing exposure time. The glutathione S-transferase (GST) activity showed differences in the group exposed to Mn for 96 h compared to the group exposed for 21 days. The acetylcholinesterase (AChE) activity increased in the fish exposed for 7 days compared to the control group. On the other hand, no genotoxic changes were observed. The CT Max showed that the loss of equilibrium of 50% of the fish occurs at a temperature of 39ºC, with and without the Mn presence. Furthermore, the catalase gene expression (oxidative stress) did not show alterations.
Assuntos
Characidae , Poluentes Químicos da Água , Animais , Characidae/metabolismo , Manganês/toxicidade , Acetilcolinesterase/metabolismo , Temperatura , Poluentes Químicos da Água/análise , Estresse Oxidativo , Catalase/metabolismo , Biomarcadores/metabolismo , Brânquias/metabolismo , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Fígado/metabolismoRESUMO
The estuarine ecosystem of Madre de Dios Lagoon (MDL), in the Caribbean Coast of Costa Rica, is exposed to contamination with pesticide residues coming from the upstream agricultural areas. Biomarkers can provide a better indication of the fitness of biota in real mixture exposure scenarios than traditional lethal dose toxicity measurements. Here, we measured biomarkers of biotransformation, oxidative stress, and neurotoxicity on Astyanax aeneus, an abundant fish species in MDL. Glutathione S-transferase activity (GST), catalase activity (CAT), lipid peroxidation (LPO), and cholinesterase activity (ChE) were measured in fish collected during seven sampling campaigns, carried out between 2016 and 2018. Pesticide residues were analyzed in surface water samples collected every time fish were sampled. Residues of 25 pesticides, including fungicides, insecticides, and herbicides, were detected. The biomarkers measured in A. aeneus varied along the sampling moments, with biotransformation and oxidative stress signals showing a coupled response throughout the assessment. Furthermore, significant correlations were established between three biomarkers (GST, LPO, and CAT) and individual pesticides, as well as between GST and LPO with groups of pesticides with shared biocide action. Among pesticides, insecticide residues had a major influence on the responses observed in fish. This work demonstrates the chronic exposure to pesticide residues in MDL and how such exposure is related to physiological responses in fish that can affect their health and potentially, the trophic networks. This early warning information should be considered to improve the protection of estuarine ecosystems in the tropics.
Assuntos
Characidae , Resíduos de Praguicidas , Praguicidas , Poluentes Químicos da Água , Animais , Resíduos de Praguicidas/análise , Ecossistema , Estuários , Praguicidas/análise , Characidae/metabolismo , Biomarcadores/metabolismo , Estresse Oxidativo , Biotransformação , Poluentes Químicos da Água/análise , Glutationa Transferase/metabolismo , Catalase/metabolismoRESUMO
Copper waterborne toxicity is well understood in aquatic organisms. However, the dietary copper effects are much less known, especially in tropical fish. The toxicity of copper via the trophic route could be influenced by the composition of the food, and diets naturally impregnated with copper seem to have greater toxicity at lower concentrations than artificially impregnated ones. Thus, our objective was to investigate the effects of copper on juveniles of the Neotropical fish Hoplias malabaricus fed on live prey (Astyanax altiparanae) previously exposed to the metal (20 µg L - 1) for 96 h. The prey fish were given to H. malabaricus every 96 h, totaling 10 doses at the end of the experiment. Thus, after 40 days fish were killed and tissues were sampled. Blood showed to be the only tissue in which copper accumulated. Anemia was found and there was damage to the DNA of erythrocytes. Furthermore, ionic imbalances were observed in plasma. There was an increase in the concentration of Na+ and Cl- and a decrease in Ca2+, which were associated with increased copper uptake in the gastrointestinal tract of fish fed on copper exposed prey. All the antioxidant enzymes evaluated in the gills showed decreased activity compared to the control group. Copper seems to have interfered in the energy metabolism of H. malabaricus, since a lower condition factor and feed conversion efficiency rate were observed in fish fed with copper diet. The present study confirms the trophic route as an important copper toxicity pathway for H. malabaricus and reinforces the idea that metal toxicity can be increased when it is naturally impregnated in the prey tissues, even if the prey has been exposed to the metal only for a short period of time.
Assuntos
Characidae , Caraciformes , Poluentes Químicos da Água , Animais , Cobre/toxicidade , Antioxidantes , Poluentes Químicos da Água/toxicidade , Caraciformes/metabolismo , Characidae/metabolismo , BiomarcadoresRESUMO
Disturbance in the landscape surrounding streams can interfere with water quality and cause harm to aquatic organisms. In this study, we evaluate the influence of land use on the genetic and biochemical biomarkers of fish in streams of Brazilian savanna (Cerrado). We also evaluated whether biomarker responses are seasonally consistent. For this purpose, individuals of the Neotropical tetra fish Astyanax lacustris were exposed in cages for 96 h, in 13 streams draining agroecosystems with different degrees of disturbance during the dry and wet seasons. After exposure, blood, liver, and gills were collected for multibiomarker analyses (micronuclei, erythrocytic nuclear abnormalities, lipid peroxidation, antioxidant enzymes, and biotransformation enzyme). The results showed that the gradient of anthropic disturbance was positively associated with genotoxic damage (erythrocytic nuclear abnormalities) and negatively associated with antioxidant and biotransformation enzymes of the liver in both seasons. No association of the gradient of anthropic disturbance with the frequency of micronuclei and for most gill enzymes was found for both seasons. Landscape disturbance was also negatively associated with water quality in the wet season. These results indicate that changes in land use interfere with the genetic and biochemical processes of organisms. Thus, the multibiomarker approach may represent an effective strategy for assessing and monitoring terrestrial landscape disturbance.
Assuntos
Characidae , Poluentes Químicos da Água , Animais , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Antioxidantes/metabolismo , Pradaria , Brânquias/metabolismo , Biomarcadores/metabolismo , Characidae/metabolismo , Estresse OxidativoRESUMO
Microplastics (MPs) have been reported in fish species from several freshwater environments. However, the mechanisms underlying MPs ingestion by fish are still unclear, although they are important to determine the pathway of MPs along freshwater environments food webs. Here, we investigates a fundamental question of why wild freshwater fish ingest plastic. To address this, we conducted a laboratory experiment to assess MP fragments intake according to color (red, green, yellow, white, black, and blue) by a small omnivorous fish species Psalidodon eigenmanniorum (Characidae). Results showed that yellow and blue were the most consumed fragments, whereas fish avoided white fragments. Although it is not yet clear how plastic coloration relates to the selectivity and feeding of freshwater fish, the visual skills at a species-specific level could plausibly explain why certain colors are attractive or deterrent to a particular fish species. This data set can be used as a screening tool that could help to understand the mechanisms underlying the patterns of plastic ingestion by fish, with special emphasis on the color of plastic particles. Future research on mechanisms MPs intake by fish, also providing a multi-species approach is highly recommended.
Assuntos
Characidae , Poluentes Químicos da Água , Animais , Characidae/metabolismo , Monitoramento Ambiental/métodos , Peixes/metabolismo , Água Doce , Microplásticos , Plásticos/metabolismo , Poluentes Químicos da Água/análiseRESUMO
Predictions about global warming have raised interest in assessing whether ectothermic organisms will be able to adapt to these changes. Understanding the physiological mechanisms and metabolic adjustment capacity of fish subjected to heat stress can provide subsidies that may contribute to decision-making in relation to ecosystems and organisms subjected to global climate change. This study investigated the antioxidant defence system and energy metabolism of carbohydrate and protein responses in the gill, liver and kidney tissues of Psalidodon bifasciatus (Garavello & Sampaio 2010), a Brazilian freshwater fish used in aquaculture and in biological studies, following exposure to heat shock at 31°C for 2, 6, 12, 24 and 48 h. The fish presented signs of stress in all tissues tested, as evidenced by increased lipid peroxidation concentration at 2 h and phosphofructokinase, hexokinase and malate dehydrogenase activity at 48 h in the gills; increased glutathione-S-transferase activity at 12 h, citrate synthase activity at 24 h and concentration of reduced glutathione (GSH) concentration at 12 and 48 h in the liver; and through increased activity of superoxide dismutase at 48 h, glutathione reductase at 24 h, glucose-6-phosphate dehydrogenase at 48 h and concentration of GSH at 24 h in the kidney. In the kidneys, changes in the antioxidant system were more prominent, whereas in the gills, there were greater changes in the carbohydrate metabolism. These results indicated the importance of glycolysis and aerobic metabolism in the gills, aerobic metabolism in the liver and pentose-phosphate pathway in the kidneys during homeostasis. The biomarker response was tissue specific, with the greatest number of biomarkers altered in the gills, followed by those in the kidneys and liver.
Assuntos
Antioxidantes , Characidae , Animais , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Characidae/metabolismo , Ecossistema , Metabolismo Energético , Brânquias/metabolismo , Glutationa/metabolismo , Glutationa/farmacologia , Glutationa Peroxidase/metabolismo , Glutationa Peroxidase/farmacologia , Resposta ao Choque Térmico , Peroxidação de Lipídeos , Fígado/metabolismo , Estresse Oxidativo , Superóxido Dismutase/metabolismo , Superóxido Dismutase/farmacologiaRESUMO
Subtropical fish are exposed to seasonal variations in temperature that impose a set of adaptations on their metabolism necessary for the maintenance of homeostasis. In this study, we addressed the effects of temperature variation on the metabolism of Astyanax lacustris, a species of freshwater fish common in the subtropical region of Brazil. Biomarkers of carbohydrate and protein metabolism, antioxidant defense, and oxidative damage were evaluated in the liver of A. lacustris exposed to low (15 °C) and high (31 °C) temperature thermal shock, with controls at 23 °C for 2, 6, 12, 24, 48, 72, and 96 h. A high energy demand was observed during the first 48 h of exposure to 15 °C, which is necessary for metabolic adjustment at low temperatures, with an increase in glycolysis, citric acid cycle, and amino acid catabolism. In addition, at 31 °C, glucose was exported in the first 12 h of exposure, and an increase in the citric acid cycle suggested acetyl-CoA as the pathway substrate, originating from the oxidation of lipids. The antioxidant defenses did not change at 15 °C, as opposed to 31 °C, in which there were changes in several antioxidant defense markers, indicating a response to the production of ROS. However, oxidative stress was observed at both temperatures, with oxidative damage detected by lipid peroxidation at 15 °C and protein carbonylation at 31 °C.