Behavioral and biochemical consequences after chronic exposition to the herbicide atrazine in tadpoles.

Atrazine (ATZ) is the third most sold herbicide in Brazil, occupying the seventh position between most widely used pesticides. Due to its easy outflow, low reactivity and solubility, moderate adsorption to organic matter and clay, and long soil persistence, residual herbicide can be identified after long periods following application, and its usage has been prohibited in diverse countries. Amphibians are important bioindicators to assess impact of pesticide like atrazine, due to having a partial aquatic life cycle. This study had as objective to assess the response of bullfrog (Lithobates catesbeianus) tadpoles when exposed to this herbicide. Animals were exposed for a total of 168h to following concentrations: negative control, 40 µg/L, 200 µg/L, 2000 µg/L, 20000 µg/L of ATZ. Analysis of swimming activity was performed, and biochemical profile was assessed by analysis of blood and plasma glucose levels, urea, creatinine, cholesterol, HDL, triglycerides, glutamic pyruvic transaminase (GPT), alkaline phosphatase (AP), calcium, total proteins, phenol, peroxidase and polyphenol oxidase activity. Results exhibited malnutrition, anemia, likely muscle mass loss, and hepatic damage, indicating that ATZ can lead to an increase in energy to maintain homeostasis for animal survival.

Atrazine contaminated sites and bullfrog tadpoles: evasive trends and biochemical consequences.

Atrazine (ATZ) is one of the most used active principles in agricultural systems. This pesticide has the ability to easily accumulate in terrestrial and aquatic environments, causing impacts with chronic adverse effects. Avoidance tests are tests that seek to assess the concentration from which a given organism escapes, that is, migrates to another habitat. They are being used as a modality of innovative and minimally invasive ecotoxicological tests. Our objective was to evaluate the sensitivity and possible toxic effects of ATZ in bullfrog tadpoles (Lithobates catesbeianus), through avoidance tests and oxidative stress analyses. We performed the behavioral avoidance test lasting 12 h, with observations every 60 min in a linear multi-compartment system with seven compartments. Each compartment corresponded to a concentration: negative control, 1, 2, 20, 200, 2000, 20,000 µg L-1. After the selection of habitat, organisms were forcedly maintained in the chosen concentrations for 48 h and then, metabolic effects were measured assessing the blood plasma amino acid profile and liver protein degradation. We also determined the effective concentrations of ATZ tested at 0 h and 48 h. The results showed that there was an effect of the treatment on the distribution of tadpoles, but not on the hours or on the combined effect (interaction). The biochemical analyses also showed a concentration-dependent relationship which caused significant toxic effects even in a short period of time. In conclusion, these frogs were able to avoid places with high concentrations of ATZ in the first hours of exposure, which suggests that in the natural environment these animals can migrate or avoid areas contaminated by this herbicide; however, depending on the selected concentration, serious biochemical consequences can occur.

Histopathological changes in Lithobates catesbeianustadpoles used as biomarkers of pesticide poisoning / Alterações histopatológicas utilizadas em girinos de Lithobates catesbeianuscomo biomarcadores de intoxicações causadas por pesticidas

The use of biological indicators has increased in recent years with the aim of investigating environ-mental pollution in aquatic environments that are vulnerable to the constant use of pesticides. Some biomarkers can help assess the health status, indicating physical, metabolic, and behavioral changes under acute and sublethal poisoning. The mixture of the active ingredients cyproconazole and pico-xystrobin is a widely used fungicide for the control of pests in cotton, rice, coffee, sugarcane, corn, soybean, and wheat. The objective of this study was to verify the occurrence of possible histopatholo-gical lesions in the liver and kidneys of bullfrog tadpoles (Lithobates catesbeianus) caused by a fungi-cide commercial formula composed of picoxystrobin and cyproconazole. The animals were subjected to different concentrations of the fungicide to determine the median lethal concentration (LC50-96h = 0.05 mg L-1), that is, the lethal dose for 50% of the animals in 96 h. After determining the value of LC50-96h, the animals were subjected to three sublethal concentrations (LC50-96h/2, LC50-96h/10, and LC-50-96h/100). Through histological biomarkers, it was verified that this fungicide changed the morphology of the animals' kidney and liver tissues in a chronic way, impairing the functioning of organs that are essential for their survival and metamorphosis, which can result in an imbalance in the biodiversity of aquatic ecosystems.(AU)

O uso de indicadores biológicos tem aumentado nos últimos anos, com o intuito de investigar a po-luição ambiental em ambientes aquáticos que são vulneráveis ao constante uso de pesticidas. Alguns biomarcadores podem ajudar a avaliar o estado de saúde, indicando alterações físicas, metabólicas e comportamentais de intoxicações agudas e subletais. A mistura dos ingredientes ativos picoxistrobina e ciproconazol é amplamente usada como fungicida para o controle de pragas da cultura de algodão, arroz, café, cana-de-açúcar, milho, soja e trigo. O objetivo deste trabalho foi verificar a ocorrência de possíveis lesões histopatológicas em fígado e rins de girinos de rã-touro (Lithobates catesbeianus) causadas pela mistura dos fungicidas picoxistrobina e ciproconazol. Os animais foram submetidos a diferentes concentrações do fungicida para determinação da concentração letal mediana (CL50-96h = 0,05 mg L-1), ou seja, a dose letal para 50% dos animais em 96 horas. Após a determinação do valor da CL50-96h, os animais foram submetidos a três concentrações subletais (CL50-96h/2, CL50-96h/10 e CL50-96h/100). Através dos biomarcadores histológicos, a pesquisa verificou que esse fungicida alterou a morfolo-gia dos tecidos renais e hepáticos dos animais de maneira crônica, prejudicando o funcionamento de órgãos que são fundamentais para sua sobrevivência e metamorfose, o que pode resultar em um desequilíbrio para a biodiversidade dos ecossistemas aquáticos.(AU)

Genomic sequencing of a frog virus 3 strain from cultured American bullfrogs (Lithobates catesbeianus) in Brazil.

Frog virus 3 (FV3) was detected in cultured bullfrogs in Southeast Brazil. Phylodynamic analysis revealed recombination events in this strain that were nearly identical to those detected in North American and Brazilian FV3 strains. These data suggest that international trade of live bullfrogs has spread recombinant strains of FV3.

Toxic effects in Aphanomyces brasiliensis and zebrafish embryos caused by oomyceticides.

In fish farming, high losses occur during egg incubation and larviculture due to diseases caused by oomycetes. This study aimed to identify the oomycete species that occurs in zebrafish Danio rerio eggs and to evaluate the oomyceticidal effect of copper sulfate, bronopol and methylene blue on the mycelial growth of this organism, as well as to determine the lethal and sublethal toxicity of these compounds in embryos of D. rerio. The isolates were cultivated in yeast-starch medium to determine the concentration necessary to inhibit mycelial growth by 50% (IC50) and 100% (minimum oomyceticidal concentration) after a 96 h exposure to these compounds. In addition, tests with D. rerio eggs were conducted to determine the lethal concentrations for 50% of the organisms (96h-LC50), and the concentrations that inhibited 17% of the eggs hatching (96h-IC17) after 96 h. The organism responsible for the mortality of D. rerio eggs was classified by classical and molecular methods as Aphanomyces brasiliensis, representing the first report of this pathogen in zebrafish eggs. IC50 values could be determined for both bronopol and copper sulfate, whereas methylene blue had low effectiveness against the oomycete. Copper showed high toxicity to D. rerio eggs at low concentrations, while methylene blue and bronopol toxicity was low and similar to each other. The use of bronopol at a concentration of 4.8 mg l-1 for the treatment of zebrafish eggs allows controlling the pathology without causing deleterious effects to the treated organisms.

Experimental Frog Virus 3 infection using Brazilian strain: amphibians susceptibility / Infecção experimental utilizando estirpe brasileira de Frog Virus 3: suceptibilidade de anfíbios

An alarming number of global warnings concerning amphibian mortality outbreaks have been released in recent years. Emerging diseases stand out as the main potential causes. Ranavirus is a worldwide-spread highly infectious disease capable of affecting even other ectothermic animals such as fish and reptiles. One major issue regarding this pathology is the lack of clinical signs before it leads up to death. Aiming at having a better understanding of anurans susceptibility, this study analyzed bullfrog (Lithobates catesbeianus) survival rate, when challenged with three doses of a Brazilian strain of Frog Virus 3 (FV3). The qPCR analysis indicated a low infectivity rate in these animals both as larvae and as adults. To elucidate the results, the following hypothesis was performed: 1) The amount of inoculum used on the frogs was insufficient to trigger an infection; 2) For the FV3 to produce clinical signs in this species, there is the need for a cofactor; 3) The animals did undergo FV3 infection but recovered in the course of the experiment, and 4) The inoculum utilized might have been low-virulence. Finally, the presence of actual clinical signs of ranavirus is discussed, with the more likely hypothesis.

Um número alarmante de notificações globais sobre surtos de mortalidade de anfíbios tem sido realizado nos últimos anos. As doenças emergentes destacam-se como as principais causas potenciais. O ranavírus é uma doença altamente infecciosa disseminada em todo o mundo, capaz de afetar até outros animais ectotérmicos como peixes e répteis. Uma questão importante em relação a essa patologia é a falta de sinais clínicos antes de levar à morte. Com o objetivo de compreender melhor a suscetibilidade dos anuros, o presente trabalho analisou a taxa de sobrevivência de rãs-touro (Lithobates catesbeianus), desafiadas com três doses de uma estirpe brasileira do Frog virus 3 (FV3). A análise de qPCR indicou baixa taxa de infectividade nesses animais, tanto como larvas quanto como adultos. Procurando esclarecer os resultados, foram formuladas as seguintes hipóteses: 1) A quantidade de inóculo aplicada nas rãs foi insuficiente para desencadear uma infecção; 2) Para que o FV3 dê sinais clínicos nesta espécie, é necessário um cofator; 3) Os animais sofreram infecção por FV3, mas se recuperaram no decorrer do experimento, e 4) O inóculo utilizado pode ter sido de baixa virulência. Finalmente, foi discutida a presença de sinais clínicos reais de ranavírus e levantada a hipótese mais provável.

Experimental Frog Virus 3 infection using Brazilian strain: amphibians susceptibility / Infecção experimental utilizando estirpe brasileira de Frog Virus 3: suceptibilidade de anfíbios

An alarming number of global warnings concerning amphibian mortality outbreaks have been released in recent years. Emerging diseases stand out as the main potential causes. Ranavirus is a worldwide-spread highly infectious disease capable of affecting even other ectothermic animals such as fish and reptiles. One major issue regarding this pathology is the lack of clinical signs before it leads up to death. Aiming at having a better understanding of anurans susceptibility, this study analyzed bullfrog (Lithobates catesbeianus) survival rate, when challenged with three doses of a Brazilian strain of Frog Virus 3 (FV3). The qPCR analysis indicated a low infectivity rate in these animals both as larvae and as adults. To elucidate the results, the following hypothesis was performed: 1) The amount of inoculum used on the frogs was insufficient to trigger an infection; 2) For the FV3 to produce clinical signs in this species, there is the need for a cofactor; 3) The animals did undergo FV3 infection but recovered in the course of the experiment, and 4) The inoculum utilized might have been low-virulence. Finally, the presence of actual clinical signs of ranavirus is discussed, with the more likely hypothesis.

Um número alarmante de notificações globais sobre surtos de mortalidade de anfíbios tem sido realizado nos últimos anos. As doenças emergentes destacam-se como as principais causas potenciais. O ranavírus é uma doença altamente infecciosa disseminada em todo o mundo, capaz de afetar até outros animais ectotérmicos como peixes e répteis. Uma questão importante em relação a essa patologia é a falta de sinais clínicos antes de levar à morte. Com o objetivo de compreender melhor a suscetibilidade dos anuros, o presente trabalho analisou a taxa de sobrevivência de rãs-touro (Lithobates catesbeianus), desafiadas com três doses de uma estirpe brasileira do Frog virus 3 (FV3). A análise de qPCR indicou baixa taxa de infectividade nesses animais, tanto como larvas quanto como adultos. Procurando esclarecer os resultados, foram formuladas as seguintes hipóteses: 1) A quantidade de inóculo aplicada nas rãs foi insuficiente para desencadear uma infecção; 2) Para que o FV3 dê sinais clínicos nesta espécie, é necessário um cofator; 3) Os animais sofreram infecção por FV3, mas se recuperaram no decorrer do experimento, e 4) O inóculo utilizado pode ter sido de baixa virulência. Finalmente, foi discutida a presença de sinais clínicos reais de ranavírus e levantada a hipótese mais provável.

Experimental Frog Virus 3 infection using Brazilian strain: amphibians susceptibility / Infecção experimental utilizando estirpe brasileira de Frog Virus 3: suceptibilidade de anfíbios

An alarming number of global warnings concerning amphibian mortality outbreaks have been released in recent years. Emerging diseases stand out as the main potential causes. Ranavirus is a worldwide-spread highly infectious disease capable of affecting even other ectothermic animals such as fish and reptiles. One major issue regarding this pathology is the lack of clinical signs before it leads up to death. Aiming at having a better understanding of anurans susceptibility, this study analyzed bullfrog (Lithobates catesbeianus) survival rate, when challenged with three doses of a Brazilian strain of Frog Virus 3 (FV3). The qPCR analysis indicated a low infectivity rate in these animals both as larvae and as adults. To elucidate the results, the following hypothesis was performed: 1) The amount of inoculum used on the frogs was insufficient to trigger an infection; 2) For the FV3 to produce clinical signs in this species, there is the need for a cofactor; 3) The animals did undergo FV3 infection but recovered in the course of the experiment, and 4) The inoculum utilized might have been low-virulence. Finally, the presence of actual clinical signs of ranavirus is discussed, with the more likely hypothesis.(AU)

Um número alarmante de notificações globais sobre surtos de mortalidade de anfíbios tem sido realizado nos últimos anos. As doenças emergentes destacam-se como as principais causas potenciais. O ranavírus é uma doença altamente infecciosa disseminada em todo o mundo, capaz de afetar até outros animais ectotérmicos como peixes e répteis. Uma questão importante em relação a essa patologia é a falta de sinais clínicos antes de levar à morte. Com o objetivo de compreender melhor a suscetibilidade dos anuros, o presente trabalho analisou a taxa de sobrevivência de rãs-touro (Lithobates catesbeianus), desafiadas com três doses de uma estirpe brasileira do Frog virus 3 (FV3). A análise de qPCR indicou baixa taxa de infectividade nesses animais, tanto como larvas quanto como adultos. Procurando esclarecer os resultados, foram formuladas as seguintes hipóteses: 1) A quantidade de inóculo aplicada nas rãs foi insuficiente para desencadear uma infecção; 2) Para que o FV3 dê sinais clínicos nesta espécie, é necessário um cofator; 3) Os animais sofreram infecção por FV3, mas se recuperaram no decorrer do experimento, e 4) O inóculo utilizado pode ter sido de baixa virulência. Finalmente, foi discutida a presença de sinais clínicos reais de ranavírus e levantada a hipótese mais provável(AU)

Experimental Frog Virus 3 infection using Brazilian strain: amphibians susceptibility / Infecção experimental utilizando estirpe brasileira de Frog Virus 3: suceptibilidade de anfíbios

An alarming number of global warnings concerning amphibian mortality outbreaks have been released in recent years. Emerging diseases stand out as the main potential causes. Ranavirus is a worldwide-spread highly infectious disease capable of affecting even other ectothermic animals such as fish and reptiles. One major issue regarding this pathology is the lack of clinical signs before it leads up to death. Aiming at having a better understanding of anurans susceptibility, this study analyzed bullfrog (Lithobates catesbeianus) survival rate, when challenged with three doses of a Brazilian strain of Frog Virus 3 (FV3). The qPCR analysis indicated a low infectivity rate in these animals both as larvae and as adults. To elucidate the results, the following hypothesis was performed: 1) The amount of inoculum used on the frogs was insufficient to trigger an infection; 2) For the FV3 to produce clinical signs in this species, there is the need for a cofactor; 3) The animals did undergo FV3 infection but recovered in the course of the experiment, and 4) The inoculum utilized might have been low-virulence. Finally, the presence of actual clinical signs of ranavirus is discussed, with the more likely hypothesis.(AU)

Um número alarmante de notificações globais sobre surtos de mortalidade de anfíbios tem sido realizado nos últimos anos. As doenças emergentes destacam-se como as principais causas potenciais. O ranavírus é uma doença altamente infecciosa disseminada em todo o mundo, capaz de afetar até outros animais ectotérmicos como peixes e répteis. Uma questão importante em relação a essa patologia é a falta de sinais clínicos antes de levar à morte. Com o objetivo de compreender melhor a suscetibilidade dos anuros, o presente trabalho analisou a taxa de sobrevivência de rãs-touro (Lithobates catesbeianus), desafiadas com três doses de uma estirpe brasileira do Frog virus 3 (FV3). A análise de qPCR indicou baixa taxa de infectividade nesses animais, tanto como larvas quanto como adultos. Procurando esclarecer os resultados, foram formuladas as seguintes hipóteses: 1) A quantidade de inóculo aplicada nas rãs foi insuficiente para desencadear uma infecção; 2) Para que o FV3 dê sinais clínicos nesta espécie, é necessário um cofator; 3) Os animais sofreram infecção por FV3, mas se recuperaram no decorrer do experimento, e 4) O inóculo utilizado pode ter sido de baixa virulência. Finalmente, foi discutida a presença de sinais clínicos reais de ranavírus e levantada a hipótese mais provável(AU)

Experimental Frog Virus 3 infection using Brazilian strain: amphibians susceptibility / Infecção experimental utilizando estirpe brasileira de Frog Virus 3: suceptibilidade de anfíbios

An alarming number of global warnings concerning amphibian mortality outbreaks have been released in recent years. Emerging diseases stand out as the main potential causes. Ranavirus is a worldwide-spread highly infectious disease capable of affecting even other ectothermic animals such as fish and reptiles. One major issue regarding this pathology is the lack of clinical signs before it leads up to death. Aiming at having a better understanding of anurans susceptibility, this study analyzed bullfrog (Lithobates catesbeianus) survival rate, when challenged with three doses of a Brazilian strain of Frog Virus 3 (FV3). The qPCR analysis indicated a low infectivity rate in these animals both as larvae and as adults. To elucidate the results, the following hypothesis was performed: 1) The amount of inoculum used on the frogs was insufficient to trigger an infection; 2) For the FV3 to produce clinical signs in this species, there is the need for a cofactor; 3) The animals did undergo FV3 infection but recovered in the course of the experiment, and 4) The inoculum utilized might have been low-virulence. Finally, the presence of actual clinical signs of ranavirus is discussed, with the more likely hypothesis.

Um número alarmante de notificações globais sobre surtos de mortalidade de anfíbios tem sido realizado nos últimos anos. As doenças emergentes destacam-se como as principais causas potenciais. O ranavírus é uma doença altamente infecciosa disseminada em todo o mundo, capaz de afetar até outros animais ectotérmicos como peixes e répteis. Uma questão importante em relação a essa patologia é a falta de sinais clínicos antes de levar à morte. Com o objetivo de compreender melhor a suscetibilidade dos anuros, o presente trabalho analisou a taxa de sobrevivência de rãs-touro (Lithobates catesbeianus), desafiadas com três doses de uma estirpe brasileira do Frog virus 3 (FV3). A análise de qPCR indicou baixa taxa de infectividade nesses animais, tanto como larvas quanto como adultos. Procurando esclarecer os resultados, foram formuladas as seguintes hipóteses: 1) A quantidade de inóculo aplicada nas rãs foi insuficiente para desencadear uma infecção; 2) Para que o FV3 dê sinais clínicos nesta espécie, é necessário um cofator; 3) Os animais sofreram infecção por FV3, mas se recuperaram no decorrer do experimento, e 4) O inóculo utilizado pode ter sido de baixa virulência. Finalmente, foi discutida a presença de sinais clínicos reais de ranavírus e levantada a hipótese mais provável.

Experimental Frog Virus 3 infection using Brazilian strain: amphibians susceptibility / Infecção experimental utilizando estirpe brasileira de Frog Virus 3: suceptibilidade de anfíbios

An alarming number of global warnings concerning amphibian mortality outbreaks have been released in recent years. Emerging diseases stand out as the main potential causes. Ranavirus is a worldwide-spread highly infectious disease capable of affecting even other ectothermic animals such as fish and reptiles. One major issue regarding this pathology is the lack of clinical signs before it leads up to death. Aiming at having a better understanding of anurans susceptibility, this study analyzed bullfrog (Lithobates catesbeianus) survival rate, when challenged with three doses of a Brazilian strain of Frog Virus 3 (FV3). The qPCR analysis indicated a low infectivity rate in these animals both as larvae and as adults. To elucidate the results, the following hypothesis was performed: 1) The amount of inoculum used on the frogs was insufficient to trigger an infection; 2) For the FV3 to produce clinical signs in this species, there is the need for a cofactor; 3) The animals did undergo FV3 infection but recovered in the course of the experiment, and 4) The inoculum utilized might have been low-virulence. Finally, the presence of actual clinical signs of ranavirus is discussed, with the more likely hypothesis.

Um número alarmante de notificações globais sobre surtos de mortalidade de anfíbios tem sido realizado nos últimos anos. As doenças emergentes destacam-se como as principais causas potenciais. O ranavírus é uma doença altamente infecciosa disseminada em todo o mundo, capaz de afetar até outros animais ectotérmicos como peixes e répteis. Uma questão importante em relação a essa patologia é a falta de sinais clínicos antes de levar à morte. Com o objetivo de compreender melhor a suscetibilidade dos anuros, o presente trabalho analisou a taxa de sobrevivência de rãs-touro (Lithobates catesbeianus), desafiadas com três doses de uma estirpe brasileira do Frog virus 3 (FV3). A análise de qPCR indicou baixa taxa de infectividade nesses animais, tanto como larvas quanto como adultos. Procurando esclarecer os resultados, foram formuladas as seguintes hipóteses: 1) A quantidade de inóculo aplicada nas rãs foi insuficiente para desencadear uma infecção; 2) Para que o FV3 dê sinais clínicos nesta espécie, é necessário um cofator; 3) Os animais sofreram infecção por FV3, mas se recuperaram no decorrer do experimento, e 4) O inóculo utilizado pode ter sido de baixa virulência. Finalmente, foi discutida a presença de sinais clínicos reais de ranavírus e levantada a hipótese mais provável.

Genome analysis of Ranavirus frog virus 3 isolated from American Bullfrog (Lithobates catesbeianus) in South America.

Ranaviruses (family Iridoviridae) cause important diseases in cold-blooded vertebrates. In addition, some occurrences indicate that, in this genus, the same virus can infect animals from different taxonomic groups. A strain isolated from a Ranavirus outbreak (2012) in the state of Sao Paulo, Brazil, had its genome sequenced and presented 99.26% and 36.85% identity with samples of Frog virus 3 (FV3) and Singapore grouper iridovirus (SGIV) ranaviruses, respectively. Eight potential recombination events among the analyzed sample and reference FV3 samples were identified, including a recombination with Bohle iridovirus (BIV) sample from Oceania. The analyzed sample presented several rearrangements compared to FV3 reference samples from North America and European continent. We report for the first time the complete genome of Ranavirus FV3 isolated from South America, these results contribute to a greater knowledge related to evolutionary events of potentially lethal infectious agent for cold-blooded animals.

Acute toxic and genotoxic effects of formalin in Danio rerio (zebrafish).

Formalin is a readily soluble chemical used as a sanitizing agent in the home and hospital. Formaldehyde solutions are routinely used in aquaculture for the prophylaxis and treatment of parasites and fungi, but the adverse effects of their application need to be further investigated. Danio rerio or zebrafish has characteristics favorable to its handling and breeding, and it is highly sensitive to various chemicals, being an ideal experimental model for this type of investigation. Thus, the objective of this study was to verify the toxic and genotoxic effects of formalin and to determine the lethal concentrations of this chemical to support its safe use in disinfection processes. Acute and chronic tests were performed using methods in accordance with international protocols. The genotoxic effect of formalin was evaluated with the micronucleus test using blood samples, which were collected at 96 and 192 h of exposure. The LC50-96h of formalin in D. rerio was 45.73 mg L-1, demonstrating its high resistance compared to other species. Regarding the genotoxic effect, the sublethal concentrations of formalin showed a positive correlation with micronuclei according to the increase in its concentration independent of the time of exposure. The incidence of micronuclei increased with concentration, and the addition of 1 mg L-1 formalin corresponded to an increase of 2.9% in the average number of micronuclei. In other words, formalin at even sublethal concentrations caused genotoxic effects in peripheral blood erythrocytes of D. rerio. Therefore, we recommend further studies and other tests involving this chemical for its use at environmentally safe concentrations.

Use of polyclonal antibodies, electron microscopy and histopathology to detect iridovirus-like particles in bullfrogs / Uso de anticorpos policlonais, microscopia eletrônica e histologia para detecção de partículas semelhantes ao iridovírus em rãs-touro

Iridoviruses of the Ranavirus genus have been implicated in the decline in amphibians worldwide, capable of affecting animals both in the wild and in captivity. This study aimed to detect iridovirus-like particles from three frog farms in southeastern Brazil using primary polyclonal antibodies, transmission electron microscopy (TEM) and histologic findings. The target organs were liver and kidneys. Sixty adults and sixty tadpoles of bullfrogs (Lithobates catesbeianus) were used in the study. TEM revealed the presence of iridovirus-like particles in hepatic tissue using the negative staining technique. Positive results were also observed by immunoelectron microscopy and immunocytochemistry (ICC). The histological analysis of the samples showed liver hemorrhage and corpuscles inclusion in hepatocytes as well as glomerulotubular degeneration and necrosis in the kidneys. The methods used in this study were highly efficient to detect the presence of iridovirus-like particles and possible infection of ranavirus.

Os iridovirus do gênero Ranavirus têm sido implicados no declínio dos anfíbios em todo o mundo afetando animais de vida livre e aqueles em cativeiro. O objetivo deste estudo foi detectar a presença de partículas semelhantes ao iridovírus em três ranários na região sudeste do Brasil, utilizando anticorpos policlonais primários, microscopia eletrônica de transmissão (MET) e achados histológicos. Os órgãos alvo foram o fígado e os rins. Sessenta rãs-touro adultas (Lithobates catesbeianus) e sessenta girinos da mesma espécie foram usados para o estudo. A MET revelou a presença de partículas semelhantes ao iridovírus em tecido hepático utilizando a técnica de contrastação negativa. Os resultados positivos foram também observados por imunomicroscopia eletrônica e imunocitoquímica. As análises histológicas nas mesmas amostras evidenciaram hemorragia no fígado e corpúsculos de inclusão em hepatócitos, e degeneração glomerulotubular e necrose nos rins. Os métodos usados neste estudo foram altamente eficientes na detecção de partículas semelhantes ao iridovírus e possivel infecção por ranavirus.

Use of polyclonal antibodies, electron microscopy and histopathology to detect iridovirus-like particles in bullfrogs / Uso de anticorpos policlonais, microscopia eletrônica e histologia para detecção de partículas semelhantes ao iridovírus em rãs-touro

Iridoviruses of the Ranavirus genus have been implicated in the decline in amphibians worldwide, capable of affecting animals both in the wild and in captivity. This study aimed to detect iridovirus-like particles from three frog farms in southeastern Brazil using primary polyclonal antibodies, transmission electron microscopy (TEM) and histologic findings. The target organs were liver and kidneys. Sixty adults and sixty tadpoles of bullfrogs (Lithobates catesbeianus) were used in the study. TEM revealed the presence of iridovirus-like particles in hepatic tissue using the negative staining technique. Positive results were also observed by immunoelectron microscopy and immunocytochemistry (ICC). The histological analysis of the samples showed liver hemorrhage and corpuscles inclusion in hepatocytes as well as glomerulotubular degeneration and necrosis in the kidneys. The methods used in this study were highly efficient to detect the presence of iridovirus-like particles and possible infection of ranavirus.(AU)

Os iridovirus do gênero Ranavirus têm sido implicados no declínio dos anfíbios em todo o mundo afetando animais de vida livre e aqueles em cativeiro. O objetivo deste estudo foi detectar a presença de partículas semelhantes ao iridovírus em três ranários na região sudeste do Brasil, utilizando anticorpos policlonais primários, microscopia eletrônica de transmissão (MET) e achados histológicos. Os órgãos alvo foram o fígado e os rins. Sessenta rãs-touro adultas (Lithobates catesbeianus) e sessenta girinos da mesma espécie foram usados para o estudo. A MET revelou a presença de partículas semelhantes ao iridovírus em tecido hepático utilizando a técnica de contrastação negativa. Os resultados positivos foram também observados por imunomicroscopia eletrônica e imunocitoquímica. As análises histológicas nas mesmas amostras evidenciaram hemorragia no fígado e corpúsculos de inclusão em hepatócitos, e degeneração glomerulotubular e necrose nos rins. Os métodos usados neste estudo foram altamente eficientes na detecção de partículas semelhantes ao iridovírus e possivel infecção por ranavirus.(AU)

Acute toxicity and ecotoxicological risk assessment of rice pesticides to Lithobates catesbeianus tadpoles.

The objective of this study was to determine the acute toxicity of some pesticides used in irrigated rice farming to Lithobates catesbeianus tadpoles. The LC 50-96h for commercial formulations containing bentazon, penoxsulam, vegetable oil, permethrin and carbofuran, separately and their mixtures, were determined at the proportions commonly used in the field. The limits of risk concentrations of these products for the studied species were also established. The LC 50-96h for tadpoles was 4,530 mg L(-1) for bentazon; 7.52 mg L(-1) for penoxsulam + 145.66 mg L(-1) of vegetable oil; 81.57 mg L(-1) for vegetable oil; 0.10 mg L(-1) for permethrin; 29.90 mg L(-1) for carbofuran (active ingredients), and 38.79 times the dose used in the field for the mixture of these products. The environmental risk was determined only for permethrin, and care should be taken when using the vegetable oil.

Resposta hepática à suplementação alimentar em rãs-touro sob condição de estresse / Liver response to dietary supplementation in bullfrog under stress condition

Evaluate the hepatoprotective effect of dietary supplementation with the probiotic (Bacillus subtilis) and with beta-glucan on bullfrog in stress of high stocking density. Animals were assigned in treatments: T1: 100 animals m-2 (control); T2: 236 animals m-2; T3: 236 animals m-2 supplemented with probiotic; T4: 236 animals m-2 supplemented with beta-glucan. Evaluated survival, weight gain (WG) and the condition of liver biochemistry and histopathology. There was no statistical difference in survival between treatments (P>0.05), but were observed significant differences for WG at 30 days, between not supplemented treatments and supplemented treatments (P 0.001). Biochemical analysis showed conditions very near among animals of control treatment and animals supplemented with beta-glucan. Histopathological analysis revealed lesions and cytoplasmic rarefaction in 100% of the samples, suggesting protein deficiency. The beta-glucan reduced the effects of stress in bullfrog and has shown hepatoprotective effect, but the probiotic Bacillus subtilis was not demonstrating the same effect.

Avaliou-se o efeito hepatoprotetor da suplementação alimentar com probiótico (Bacillus subtillis) e com betaglucana em rãs-touro submetidas à condição de estresse por adensamento. Os animais foram distribuídos nos tratamentos: T1: 100 animais m-2 (controle); T2: 236 animais m-2; T3: 236 animais m-2, suplementados com probiótico; e, T4: 236 animais m-2, suplementados com betaglucana. Avaliou-se sobrevivência, ganho em peso (GP) e a condição bioquímica e histopatológica dos fígados. Não foi observada diferença estatística para a sobrevivência (P>0,05), porém foram observadas diferenças significativas para o GP aos 30 dias, entre os tratamentos não suplementados e os suplementados (P 0,001). As avaliações bioquímicas mostraram condições muito próximas entre os animais do tratamento controle e aqueles suplementados com betaglucana. A análise histopatológica mostrou lesões e rarefação citoplasmática em 100% das amostras, sugerindo deficiência proteica. A betaglucana mostrou efeito hepatoprotetor, reduzindo os efeitos do estresse sobre o fígado de rã-touro, porém o probiótico Bacillus subtillis não apresentou o mesmo potencial.

Resposta hepática à suplementação alimentar em rãs-touro sob condição de estresse / Liver response to dietary supplementation in bullfrog under stress condition

Evaluate the hepatoprotective effect of dietary supplementation with the probiotic (Bacillus subtilis) and with beta-glucan on bullfrog in stress of high stocking density. Animals were assigned in treatments: T1: 100 animals m-2 (control); T2: 236 animals m-2; T3: 236 animals m-2 supplemented with probiotic; T4: 236 animals m-2 supplemented with beta-glucan. Evaluated survival, weight gain (WG) and the condition of liver biochemistry and histopathology. There was no statistical difference in survival between treatments (P>0.05), but were observed significant differences for WG at 30 days, between not supplemented treatments and supplemented treatments (P 0.001). Biochemical analysis showed conditions very near among animals of control treatment and animals supplemented with beta-glucan. Histopathological analysis revealed lesions and cytoplasmic rarefaction in 100% of the samples, suggesting protein deficiency. The beta-glucan reduced the effects of stress in bullfrog and has shown hepatoprotective effect, but the probiotic Bacillus subtilis was not demonstrating the same effect.(AU)

Avaliou-se o efeito hepatoprotetor da suplementação alimentar com probiótico (Bacillus subtillis) e com betaglucana em rãs-touro submetidas à condição de estresse por adensamento. Os animais foram distribuídos nos tratamentos: T1: 100 animais m-2 (controle); T2: 236 animais m-2; T3: 236 animais m-2, suplementados com probiótico; e, T4: 236 animais m-2, suplementados com betaglucana. Avaliou-se sobrevivência, ganho em peso (GP) e a condição bioquímica e histopatológica dos fígados. Não foi observada diferença estatística para a sobrevivência (P>0,05), porém foram observadas diferenças significativas para o GP aos 30 dias, entre os tratamentos não suplementados e os suplementados (P 0,001). As avaliações bioquímicas mostraram condições muito próximas entre os animais do tratamento controle e aqueles suplementados com betaglucana. A análise histopatológica mostrou lesões e rarefação citoplasmática em 100% das amostras, sugerindo deficiência proteica. A betaglucana mostrou efeito hepatoprotetor, reduzindo os efeitos do estresse sobre o fígado de rã-touro, porém o probiótico Bacillus subtillis não apresentou o mesmo potencial.(AU)

Frog farms as proposed in agribusiness aquaculture: economic viability based in feed conversion / A criação de rãs como proposta de agronegócio na aquicultura: viabilidade econômica baseada em conversão alimentar

Frog farming is an aquaculture activity that is represented little in the socioeconomic profile of Brazil, resulting in little technological investment and development in the food industry. However, the growing interest in the consumption of white and healthy meats, it has been projected as an alternative source of protein. The objective of this work was to estimate the economic viability of a commercial frog pond in the Southeast region of Brazil. The results demonstrated the high set up and operating costs, where the feed and handling were considered the two aspects that define the cost of the product. The viability of the enterprise is attained only with good zootechnical rates (feed conversion ≤ 1.5:1 in the fattening phase and ≤ 2:1 in the tadpole phase) and high selling price (US$ 21.50 to 24.00 kg-¹ minimal prices). The internal rate of return observed under the most viable conditions was 41.69% and payback of 2.33 years, rates commonly used in aquaculture. Therefore, the commercial breeding of frogs is attractive if practiced with good feed conversion rates and favorable prices for market positioning in the sale of the meat as a gourmet product.(AU)

A ranicultura é uma atividade aquícola pouco representativa no perfil socioeconômico do país, acarretando em pouco investimento tecnológico e de desenvolvimento nas indústrias de insumos. Entretanto, o crescente interesse do consumo por carnes brancas e saudáveis, projeta esta atividade como uma fonte alternativa de proteína. O objetivo desta pesquisa foi estimar a viabilidade econômica de um ranário comercial na região Sudeste do Brasil. Os resultados apontaram altos custos operacionais, onde o alimento e manejo foram considerados os dois aspectos que definem o custo do produto. Por outro lado, esse estudo demonstrou a viabilidade do empreendimento, desde que se atinjam bons índices zootécnicos e elevado preço de venda (R$ 40,85 a 45,60 kg-¹). A Taxa Interna de Retorno observada na condição mais viável foi de 41,69% e “payback” de 2,33 anos. Portanto a criação comercial de rãs torna-se atrativa quando praticada com índices de conversão alimentar favoráveis (≤ 1,5:1 na fase de engorda e ≤ 2:1 na fase de girino) e o posicionamento da comercialização da carne como produto “gourmet” de alto valor agregado.(AU)

Frog farms as proposed in agribusiness aquaculture: economic viability based in feed conversion / A criação de rãs como proposta de agronegócio na aquicultura: viabilidade econômica baseada em conversão alimentar

Frog farming is an aquaculture activity that is represented little in the socioeconomic profile of Brazil, resulting in little technological investment and development in the food industry. However, the growing interest in the consumption of white and healthy meats, it has been projected as an alternative source of protein. The objective of this work was to estimate the economic viability of a commercial frog pond in the Southeast region of Brazil. The results demonstrated the high set up andoperating costs, where the feed and handling were considered the two aspects that define the cost of the product. The viability of the enterprise is attained only with good zootechnical rates (feed conversion ≤ 1.5:1 in the fattening phase and ≤ 2:1 in the tadpole phase) and high selling price (US$ 21.50 to 24.00 kg-1­minimal prices). The internal rate of return observed under the most viable conditions was 41.69% and payback of 2.33 years, rates commonly used in aquaculture. Therefore, thecommercial breeding of frogs is attractive if practiced with good feed conversion rates and favorable prices for market positioning in the sale of the meat as a gourmet product.(AU)

A ranicultura é uma atividade aquícola pouco representativa no perfil socioeconômico do país, acarretando em pouco investimento tecnológico e de desenvolvimento nas indústrias de insumos. Entretanto, o crescente interesse do consumo por carnes brancas e saudáveis, projeta esta atividade como uma fonte alternativa de proteína. O objetivo desta pesquisa foi estimar a viabilidade econômica de um ranário comercial na região Sudeste do Brasil. Os resultados apontaram altos custos operacionais, onde o alimento e manejo foram considerados os dois aspectos que definem o custo do produto. Por outro lado, esse estudo demonstrou a viabilidade do empreendimento, desde que se atinjam bons índices zootécnicos e elevado preço de venda (R$ 40,85 a 45,60 kg-1). A Taxa Interna de Retorno observada na condição mais viável foi de 41,69% e "payback" de 2,33 anos. Portanto acriação comercial de rãs torna-se atrativa quando praticada com índices de conversão alimentar favoráveis (≤ 1,5:1 na fase de engorda e ≤ 2:1 na fase degirino) e o posicionamento da comercialização da carne como produto "gourmet" de alto valor agregado.(AU)