The goal of the present work was to determine the lethal concentration (LC50) (96h) of clomazone,... more The goal of the present work was to determine the lethal concentration (LC50) (96h) of clomazone, metsulfuron-methyl, and quinclorac, herbicides used in rice culture, for the silver catfish, Rhamdia quelen. Fingerlings were exposed to different concentrations of the herbicides. The LC50s were 7.32µL L-1 for clomazone and 395mg L-1 for quinclorac. The LC50 for metsulfuron-methyl was not obtained since all fingerlings survived even at 1200mgL-1. Probably only clomazone can lead to mortality among silver catfish reared in the rice culture system.
In this study, fish Rhamdia quelen, were exposed to different concentrations of herbicide clomazo... more In this study, fish Rhamdia quelen, were exposed to different concentrations of herbicide clomazone: 0.0 (control), 0.45 and 0.91mgL−1. After exposure for 8days to herbicide, fish were transferred to clean water for a recovery period (8days). Oxidative stress indicators such as thiobarbituric acid reactive substances (TBARS) levels and protein carbonyl content, as well as antioxidant defenses, such as catalase (CAT),
The objective of this study was to investigate the effects of commercial formulation of herbicide... more The objective of this study was to investigate the effects of commercial formulation of herbicide 2,4-D on metabolic parameters, acetylcholinesterase (AChE) activity and liver histological evaluation of silver catfish (Rhamdia quelen) exposed for 96h. AChE activity increased in brain (600 and 700mgL−1) and decreased in all concentrations tested in muscle tissue. Hepatic glycogen was reduced after 2,4-D exposure ranging from
The objective of this study was to evaluate different salt concentrations in the treatment of Ich... more The objective of this study was to evaluate different salt concentrations in the treatment of Ichthyophthirius multifiliis. Silver catfish, Rhamdia quelen, fingerlings infected with I. multifiliis were submitted to four sodium chloride concentrations (g/L): 0,1,2, and 4 for 23 days. In a second experiment, fingerlings were maintained with 4 g/L salt, but for 45 days. Treatments with 2 and 4
In this study, teleostean fish Leporinus obtusidens (piava) were exposed to different concentrati... more In this study, teleostean fish Leporinus obtusidens (piava) were exposed to different concentrations of Roundup, a glyphosate (acid equivalent) herbicide: 0 (control), 3, 6, 10, and 20 mg/L for 96 h (short-term). Acetylcholinesterase (AChE) activity was verified in brain and muscle tissues. Metabolic parameters in the liver and muscle (lactate, glycogen, glucose, protein, and ammonia), as well as some hematological parameters, were determined. Unexposed fish exhibited significantly higher brain AChE activity when compared to that of the muscle (P<0.05) (13.8+/-0.76 and 6.1+/-1.31 micromol/min/g protein, respectively). Results indicated that AChE activity significantly decreased in the brain of fish exposed to all glyphosate concentrations tested, but in the muscle this parameter was not altered. In addition, fish exposed to all glyphosate concentrations showed a significant increase in hepatic glycogen and glucose, but a significant reduction in muscle glycogen and glucose. Lactate and protein of fish exposed to all glyphosate concentrations presented a significant decrease in the liver, but did not change significantly in the muscle. Levels of ammonia in both tissues increase in fish at all glyphosate concentrations. Exposure to this herbicide produced a decrease in all hematological parameters tested. These results indicate that AChE activity as well as metabolic and hematological parameters may be good early indicators of herbicide contamination in L. obtusidens.
Fingerlings of the silver catfish (Rhamdia quelen) were exposed to three herbicides widely used i... more Fingerlings of the silver catfish (Rhamdia quelen) were exposed to three herbicides widely used in rice culture in south Brazil: clomazone, quinclorac, and metsulfuron methyl. LC50 was determined and acetylcholinesterase (AChE) activity was evaluated in brain and muscle tissue of fish exposed to different herbicide concentrations after 96h (short term). The LC50 value (nominal concentration) was 7.32 mg/L for clomazone and 395 mg/L for quinclorac, but was not obtained for metsulfuron-methyl since all fingerlings survived the highest concentration of 1200 mg/L. Brain and muscle AChE activity in unexposed fish were 17.9 and 9.08 micromol/min/g protein, respectively. Clomazone significantly inhibited AChE activity in both tissues, achieving maximal inhibition of about 83% in brain and 89% in muscle tissue. In contrast, quinclorac and metsulfuron methyl caused increases in enzyme activity in the brain (98 and 179%, respectively) and inhibitions in muscle tissue (88 and 56%, respectively). This study demonstrated short-term effects of exposure to environmentally relevant concentrations of rice field herbicides on AChE activity in brain and muscle tissue of silver catfish.
The effects of clomazone (0.5 and 1.0 mg/L) according to nominal concentrations used in paddy ric... more The effects of clomazone (0.5 and 1.0 mg/L) according to nominal concentrations used in paddy rice fields (0.4-0.7 mg/L) on protein and carbohydrate metabolism and haematological parameters were evaluated in silver catfish (Rhamdia quelen) after 12, 24, 48, 96 and 192 h of exposure with a recovery period of 96 and 192 h. Liver glycogen increased significantly (P<0.05) in all periods and concentrations tested. The maximum glycogen increase reaches 250% after 12h of exposure. Muscle glycogen reduced significantly after 24, 48, 96 and 192 h for both clomazone concentrations (P<0.05). Significantly elevated plasma glucose values (P<0.05) and variation in glucose in the liver and muscle of exposed fish were observed. Muscle lactate levels increased after 12, 24 and 48 h of clomazone exposure (22-67%), but reduced in the liver (P<0.05). Protein levels were enhanced in the liver and white muscle, except at 96 and 192 h of exposure, whereas it increased in the plasma in the period from 48 to 96 h (P<0.05). Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were significantly elevated in the plasma (P<0.05). In the liver, ALT increased after 24 h, while AST activity was enhanced only after 12 h of exposure. Hematocrit contents were reduced after 96 and 192 h of exposure. Most of the metabolic disorders observed did not persist after the recovery period, except for the liver AST and ALT activity. Clomazone concentrations used in this study appear safe to fish, Rhamdia quelen, because overall parameters can be recovered after 96 and 192 h in clean water. ALT and AST activity may be an early biomarker of clomazone toxicity.
A insercao de atividades escolares educativas com maior participacao do aluno no processo de ensi... more A insercao de atividades escolares educativas com maior participacao do aluno no processo de ensino-aprendizagem colabora com o seu desenvolvimento critico, oportunizando momentos de interacao entre os participantes. O projeto “Projetando Pesquisa na Ciencia” visou realizar uma vivencia do processo de revisao de conteudos de forma dinâmica, possibilitando ao educando momentos de pesquisa e de conhecimento cientifico com atividades construtivas, ludicas com orientacao para a revisao dos conteudos trabalhados em ciencias. Assim, proporcionando aos educandos a construcao de um conhecimento questionador, dinâmico e concreto. Contudo, o desenvolvimento deste projeto em uma mostra expositiva e interativa, com varias reflexoes ligadas aos conteudos didaticos, proporcionou o processo de ensino-aprendizagem com a interacao entre os alunos-professores. Neste contexto, as trocas de ideias potencializaram a revisao dos conteudos colaborando com a compreensao de todas as ciencias e teorias envol...
The aim of the present study was to determine the effects of waterborne un-ionized ammonia (NH3) ... more The aim of the present study was to determine the effects of waterborne un-ionized ammonia (NH3) on the survival and growth of silver catfish (Rhamdia quelen). Juveniles were exposed to 0.10, 0.22, and 0.42mg L-1 NH3 at pH 8.2 for 45 days. After 15 days, a significant mortality rate (33%) was observed in the fish exposed to 0.42mg L-1 NH3. After 20 days, 23% and 43% mortality (both significant) was observed in fish exposed to 0.22 and 0.42mg L-1 NH3, respectively. A significant negative relationship between survival, length, daily weight gain, standard growth rate, and biomass of juveniles of silver catfish per tank with waterborne NH3 levels was found at the end of the experiment. The resulting survival and waterborne NH3 relationship indicated that, to avoid any mortality of silver catfish, the maximum level of chronic NH3 exposure at pH 8.2 would be 0.01mg L-1.
ABSTRACT This study investigated the efficacy of the essential oil of Aloysia triphylla in the tr... more ABSTRACT This study investigated the efficacy of the essential oil of Aloysia triphylla in the transport of silver catfish (Rhamdia quelen) considering survival, water quality, ionoregulatory balance and biochemical parameters. Fish (262.0 ± 73.5 g) were divided into three groups: 0 (control), 30 or 40 μL/L EO of A. triphylla was added to the water and transported in plastic bags for 6 h. At the end of transport, dissolved oxygen, alkalinity, pH, temperature, and un-ionized ammonia levels in the water of transport were not significantly different between treatments, but the control group presented the highest total ammonia levels. Fish transported with the EO of A. triphylla had lower plasma cortisol and ion loss and higher plasma Na+ and Cl− levels than control group. Hepatic glycogen, lactate and glucose levels were lower in the liver of fish transported with EO of A. triphylla when compared to the control. Total free amino acids and protein values in the liver were higher in the treatment with 40 μL/L EO of A. triphylla. Muscle lactate and glucose levels were higher and lower, respectively, in fish transported with EO of A. triphylla compared to control fish. Thiobarbituric acid-reactive substance levels in the liver and muscle were lower in silver catfish transported with EO of A. triphylla when compared to the control fish. Catalase (CAT) activity was lower in the kidney and higher in the gill of fish transported with EO of A. triphylla when compared to controls. On the other hand, hepatic CAT activity was lower and higher in fish transported with 30 and 40 μL/L EO of A. triphylla, respectively, when compared to controls. Protein carbonyl contents of fish transported with EO of A. triphylla were lower when compared to the control. Based on the reduced plasma cortisol levels, ammonia excretion, ionoregulatory changes and improved fish oxidative status, the use of EO of A. triphylla in the water of transport is advisable for fish transportation, 40 μL/L being the best concentration.
The goal of the present work was to determine the lethal concentration (LC50) (96h) of clomazone,... more The goal of the present work was to determine the lethal concentration (LC50) (96h) of clomazone, metsulfuron-methyl, and quinclorac, herbicides used in rice culture, for the silver catfish, Rhamdia quelen. Fingerlings were exposed to different concentrations of the herbicides. The LC50s were 7.32µL L-1 for clomazone and 395mg L-1 for quinclorac. The LC50 for metsulfuron-methyl was not obtained since all fingerlings survived even at 1200mgL-1. Probably only clomazone can lead to mortality among silver catfish reared in the rice culture system.
In this study, fish Rhamdia quelen, were exposed to different concentrations of herbicide clomazo... more In this study, fish Rhamdia quelen, were exposed to different concentrations of herbicide clomazone: 0.0 (control), 0.45 and 0.91mgL−1. After exposure for 8days to herbicide, fish were transferred to clean water for a recovery period (8days). Oxidative stress indicators such as thiobarbituric acid reactive substances (TBARS) levels and protein carbonyl content, as well as antioxidant defenses, such as catalase (CAT),
The objective of this study was to investigate the effects of commercial formulation of herbicide... more The objective of this study was to investigate the effects of commercial formulation of herbicide 2,4-D on metabolic parameters, acetylcholinesterase (AChE) activity and liver histological evaluation of silver catfish (Rhamdia quelen) exposed for 96h. AChE activity increased in brain (600 and 700mgL−1) and decreased in all concentrations tested in muscle tissue. Hepatic glycogen was reduced after 2,4-D exposure ranging from
The objective of this study was to evaluate different salt concentrations in the treatment of Ich... more The objective of this study was to evaluate different salt concentrations in the treatment of Ichthyophthirius multifiliis. Silver catfish, Rhamdia quelen, fingerlings infected with I. multifiliis were submitted to four sodium chloride concentrations (g/L): 0,1,2, and 4 for 23 days. In a second experiment, fingerlings were maintained with 4 g/L salt, but for 45 days. Treatments with 2 and 4
In this study, teleostean fish Leporinus obtusidens (piava) were exposed to different concentrati... more In this study, teleostean fish Leporinus obtusidens (piava) were exposed to different concentrations of Roundup, a glyphosate (acid equivalent) herbicide: 0 (control), 3, 6, 10, and 20 mg/L for 96 h (short-term). Acetylcholinesterase (AChE) activity was verified in brain and muscle tissues. Metabolic parameters in the liver and muscle (lactate, glycogen, glucose, protein, and ammonia), as well as some hematological parameters, were determined. Unexposed fish exhibited significantly higher brain AChE activity when compared to that of the muscle (P<0.05) (13.8+/-0.76 and 6.1+/-1.31 micromol/min/g protein, respectively). Results indicated that AChE activity significantly decreased in the brain of fish exposed to all glyphosate concentrations tested, but in the muscle this parameter was not altered. In addition, fish exposed to all glyphosate concentrations showed a significant increase in hepatic glycogen and glucose, but a significant reduction in muscle glycogen and glucose. Lactate and protein of fish exposed to all glyphosate concentrations presented a significant decrease in the liver, but did not change significantly in the muscle. Levels of ammonia in both tissues increase in fish at all glyphosate concentrations. Exposure to this herbicide produced a decrease in all hematological parameters tested. These results indicate that AChE activity as well as metabolic and hematological parameters may be good early indicators of herbicide contamination in L. obtusidens.
Fingerlings of the silver catfish (Rhamdia quelen) were exposed to three herbicides widely used i... more Fingerlings of the silver catfish (Rhamdia quelen) were exposed to three herbicides widely used in rice culture in south Brazil: clomazone, quinclorac, and metsulfuron methyl. LC50 was determined and acetylcholinesterase (AChE) activity was evaluated in brain and muscle tissue of fish exposed to different herbicide concentrations after 96h (short term). The LC50 value (nominal concentration) was 7.32 mg/L for clomazone and 395 mg/L for quinclorac, but was not obtained for metsulfuron-methyl since all fingerlings survived the highest concentration of 1200 mg/L. Brain and muscle AChE activity in unexposed fish were 17.9 and 9.08 micromol/min/g protein, respectively. Clomazone significantly inhibited AChE activity in both tissues, achieving maximal inhibition of about 83% in brain and 89% in muscle tissue. In contrast, quinclorac and metsulfuron methyl caused increases in enzyme activity in the brain (98 and 179%, respectively) and inhibitions in muscle tissue (88 and 56%, respectively). This study demonstrated short-term effects of exposure to environmentally relevant concentrations of rice field herbicides on AChE activity in brain and muscle tissue of silver catfish.
The effects of clomazone (0.5 and 1.0 mg/L) according to nominal concentrations used in paddy ric... more The effects of clomazone (0.5 and 1.0 mg/L) according to nominal concentrations used in paddy rice fields (0.4-0.7 mg/L) on protein and carbohydrate metabolism and haematological parameters were evaluated in silver catfish (Rhamdia quelen) after 12, 24, 48, 96 and 192 h of exposure with a recovery period of 96 and 192 h. Liver glycogen increased significantly (P<0.05) in all periods and concentrations tested. The maximum glycogen increase reaches 250% after 12h of exposure. Muscle glycogen reduced significantly after 24, 48, 96 and 192 h for both clomazone concentrations (P<0.05). Significantly elevated plasma glucose values (P<0.05) and variation in glucose in the liver and muscle of exposed fish were observed. Muscle lactate levels increased after 12, 24 and 48 h of clomazone exposure (22-67%), but reduced in the liver (P<0.05). Protein levels were enhanced in the liver and white muscle, except at 96 and 192 h of exposure, whereas it increased in the plasma in the period from 48 to 96 h (P<0.05). Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were significantly elevated in the plasma (P<0.05). In the liver, ALT increased after 24 h, while AST activity was enhanced only after 12 h of exposure. Hematocrit contents were reduced after 96 and 192 h of exposure. Most of the metabolic disorders observed did not persist after the recovery period, except for the liver AST and ALT activity. Clomazone concentrations used in this study appear safe to fish, Rhamdia quelen, because overall parameters can be recovered after 96 and 192 h in clean water. ALT and AST activity may be an early biomarker of clomazone toxicity.
A insercao de atividades escolares educativas com maior participacao do aluno no processo de ensi... more A insercao de atividades escolares educativas com maior participacao do aluno no processo de ensino-aprendizagem colabora com o seu desenvolvimento critico, oportunizando momentos de interacao entre os participantes. O projeto “Projetando Pesquisa na Ciencia” visou realizar uma vivencia do processo de revisao de conteudos de forma dinâmica, possibilitando ao educando momentos de pesquisa e de conhecimento cientifico com atividades construtivas, ludicas com orientacao para a revisao dos conteudos trabalhados em ciencias. Assim, proporcionando aos educandos a construcao de um conhecimento questionador, dinâmico e concreto. Contudo, o desenvolvimento deste projeto em uma mostra expositiva e interativa, com varias reflexoes ligadas aos conteudos didaticos, proporcionou o processo de ensino-aprendizagem com a interacao entre os alunos-professores. Neste contexto, as trocas de ideias potencializaram a revisao dos conteudos colaborando com a compreensao de todas as ciencias e teorias envol...
The aim of the present study was to determine the effects of waterborne un-ionized ammonia (NH3) ... more The aim of the present study was to determine the effects of waterborne un-ionized ammonia (NH3) on the survival and growth of silver catfish (Rhamdia quelen). Juveniles were exposed to 0.10, 0.22, and 0.42mg L-1 NH3 at pH 8.2 for 45 days. After 15 days, a significant mortality rate (33%) was observed in the fish exposed to 0.42mg L-1 NH3. After 20 days, 23% and 43% mortality (both significant) was observed in fish exposed to 0.22 and 0.42mg L-1 NH3, respectively. A significant negative relationship between survival, length, daily weight gain, standard growth rate, and biomass of juveniles of silver catfish per tank with waterborne NH3 levels was found at the end of the experiment. The resulting survival and waterborne NH3 relationship indicated that, to avoid any mortality of silver catfish, the maximum level of chronic NH3 exposure at pH 8.2 would be 0.01mg L-1.
ABSTRACT This study investigated the efficacy of the essential oil of Aloysia triphylla in the tr... more ABSTRACT This study investigated the efficacy of the essential oil of Aloysia triphylla in the transport of silver catfish (Rhamdia quelen) considering survival, water quality, ionoregulatory balance and biochemical parameters. Fish (262.0 ± 73.5 g) were divided into three groups: 0 (control), 30 or 40 μL/L EO of A. triphylla was added to the water and transported in plastic bags for 6 h. At the end of transport, dissolved oxygen, alkalinity, pH, temperature, and un-ionized ammonia levels in the water of transport were not significantly different between treatments, but the control group presented the highest total ammonia levels. Fish transported with the EO of A. triphylla had lower plasma cortisol and ion loss and higher plasma Na+ and Cl− levels than control group. Hepatic glycogen, lactate and glucose levels were lower in the liver of fish transported with EO of A. triphylla when compared to the control. Total free amino acids and protein values in the liver were higher in the treatment with 40 μL/L EO of A. triphylla. Muscle lactate and glucose levels were higher and lower, respectively, in fish transported with EO of A. triphylla compared to control fish. Thiobarbituric acid-reactive substance levels in the liver and muscle were lower in silver catfish transported with EO of A. triphylla when compared to the control fish. Catalase (CAT) activity was lower in the kidney and higher in the gill of fish transported with EO of A. triphylla when compared to controls. On the other hand, hepatic CAT activity was lower and higher in fish transported with 30 and 40 μL/L EO of A. triphylla, respectively, when compared to controls. Protein carbonyl contents of fish transported with EO of A. triphylla were lower when compared to the control. Based on the reduced plasma cortisol levels, ammonia excretion, ionoregulatory changes and improved fish oxidative status, the use of EO of A. triphylla in the water of transport is advisable for fish transportation, 40 μL/L being the best concentration.
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