Impact of antiparasitic used in livestock: effects of ivermectin spiked sediment in Prochilodus lineatus, an inland fishery species of South America.

Ivermectin (IVM) is a widely used antiparasitic. Concerns have been raised about its environmental effects in the wetlands of Río de la Plata basin where cattle have been treated with IVM for years. This study investigated the sublethal effects of environmentally relevant IVM concentrations in sediments on the Neotropical fish Prochilodus lineatus. Juvenile P. lineatus were exposed to IVM-spiked sediments (2 and 20 µg/Kg) for 14 days, alongside a control sediment treatment without IVM. Biochemical and oxidative stress responses were assessed in brain, gills, and liver tissues, including lipid damage, glutathione levels, enzyme activities, and antioxidant competence. Muscle and brain acetylcholinesterase activity (AChE) and stable isotopes of 13C and 15N in muscle were also measured. The lowest IVM treatment resulted in an increase in brain lipid peroxidation, as measured by thiobarbituric acid reactive substances (TBARs), decreased levels of reduced glutathione (GSH) in gills and liver, increased catalase activity (CAT) in the liver, and decreased antioxidant capacity against peroxyl radicals (ACAP) in gills and liver. The highest IVM treatment significantly reduced GSH in the liver. Muscle (AChE) was decreased in both treatments. Multivariate analysis showed significant overall effects in the liver tissue, followed by gills and brain. These findings demonstrate the sublethal effects of IVM in P. lineatus, emphasizing the importance of considering sediment contamination and trophic habits in realistic exposure scenarios.

Ivermectin prevents stress-induced testicular damage in juvenile rats.

Ivermectin is a popular antiparasitic drug used in veterinary and human medicine. Studies by our group have shown that therapeutic doses of ivermectin induce some brain and behavioral impairments, especially in the reproductive sphere. So far, the studies were focused in adulthood. Considering that juveniles are more susceptible to drugs during developmental stages and both farm/domestic animals and humans have been medicated with ivermectin in youth, it is necessary to evaluate the possible harm effects in youth. The stress variable is also important, as it potentially influences the effects produced by ivermectin. Therefore, the objective of this study was to evaluate morphofunctional and hormonal reproductive aspects of juvenile rats exposed to ivermectin and/or stressed. Prepubertal male rats were treated with 0.2 or 1.0 mg/kg of ivermectin (a therapeutic dose and a higher dose, respectively). Rats were also submitted to a restraint stress session. The testis morphology and histology were analyzed and plasma testosterone levels were measured. The two doses of ivermectin did not induce a biologically relevant effect on testis and testosterone levels of rats. However, restraint stress impaired macroscopic and microscopic morphometric and stereological parameters, as well as the histology of the testis: it increased the relative testis weight, the tubular diameter, the tubular luminal diameter, and the tubular cellular index, and injured the interstitial area. Previous treatment of juvenile rats with ivermectin prevented most of the stress-induced testes injuries. In conclusion, in addition to be a remarkable antiparasitic agent, ivermectin prevented stress-induced testes injuries in juvenile rats.

Synergism of macrocyclic lactones against Haemonchus contortus.

A possible synergistic effect of macrocyclic lactones' (MLs) combination has been previously described against resistant gastrointestinal nematodes of cattle. In addition to synergism, drug-drug interactions between MLs can also result in additive or antagonistic effect, considering the different MLs pharmacokinetics, pharmacodynamics, and interactions with molecular mechanisms of resistance. Therefore, the aim of the current work was evaluated the effect of different MLs combinations against Haemonchus contortus. Infecting larvae of two isolates (one susceptible and one resistant to ivermectin) were used in the larval migration inhibition test. After estimating the half maximal effective concentration of abamectin (ABA), eprinomectin, (EPR), ivermectin (IVM), and moxidectin (MOX) for both isolates, combinations were delineated by a simplex-centroid mixture experiment, and the mixture regression analysis was applied to the special cubic model. A synergistic effect was found for the EPR + MOX against the susceptible isolate as well as the EPR + MOX, IVM + MOX, and ABA + EPR + IVM against the resistant isolate. An antagonistic effect of ABA + IVM + MOX was found against the susceptible isolate. For the susceptible isolate, a higher inhibition was found with greater proportions of EPR and lower proportions of the other drugs compared to the reference mixture. For the resistant isolate, inhibition greater than that of the reference mixture was found with higher proportions of IVM as well as lower proportions of the other drugs. The synergistic and antagonistic effects were dependent on the following: (a) parasite drug resistance profile, (b) the composition of the combination, and (c) the proportions used, with EPR and IVM exerting a greater impact on these effects.

Abamectin promotes behavior changes and liver injury in zebrafish.

The indiscriminate use of pesticides is a worldwide concern due to the environment contamination since it can cause deleterious effects to non-target organisms including the fishes. The effects of abamectin, a pesticide from the avermectin family, were evaluated in adult zebrafish (Danio rerio) after exposure to a commercial formula commonly used in Brazil. The animals were submitted to acute (96 h) and to a short-term chronic exposure (15 days) of distinct concentrations of abamectin. LC50 was determined and a histological study followed by an immunohistochemistry analysis for P-gp and HSP70 identification were performed on livers of the animals submitted to the acute and chronic treatment, respectively. Moreover, behavior patterns were observed daily in both trials. A LC50 value of 105.68 µg/L was determined. The histological analysis revealed a morphological alteration of the hepatocytes, glycogen accumulation, degeneration, and disorganization of the cytoplasm, and a pyknotic, irregular, and laterally located nuclei. The immunohistochemistry for HSP70 and P-gp showed strong staining in the hepatocytes of the control groups and progressive decrease as the concentration of abamectin increased. Changes were observed in body posture, movement around the aquarium, opercular activity, body color and search for food in the groups treated with abamectin. The results presented suggest that abamectin can affect the behavioral pattern of the animals, promote morphological changes, and decrease the expression of HSP70 and P-gp in zebrafish liver.

Development and validation of analytical methods by HPLC for quality control of avermectins and milbemycins in bulk samples

This work aims to develop analytical methods using high-performance liquid chromatography with a diode array detector (HPLC-DAD) for analysis and quantification of avermectins (AVMs) and milbemycins (MBMs) in bulk samples. First, the methods were optimized and some parameters such as temperature, flow rate, injection volume and mobile phase with different proportions of solvents were evaluated. The best chromatographic conditions were obtained using the Phenomenex® C18 (150 × 4.60 mm, 5 µm) column at a temperature of 20 °C, flow rate of 1.2 mL min-1, injection volume of 20 µL, and detection at 250 nm. Acetonitrile: ultrapure water (87: 13, v/v) was used as mobile phase for moxidectin and eprinomectin, and acetonitrile: methanol: ultrapure water (53: 35: 12, v/v/v) for abamectin and ivermectin. Under these conditions satisfactory results were obtained, with appropriate limits of detection and quantification, acceptable linearity, precision, accuracy, and robustness. These methods satisfy the need for analytical methods for the multi-determination of MBMs and the B1a and B1b forms of AVMs by HPLC-DAD, which can be considered simple, effective, innovative and should aid in the development of the fiel

Investigation of fecal egg counts versus worm burden and helminth fauna in cattle treated or not with macrocyclic lactones in a tropical region.

Gastrointestinal nematodes negatively impact the health and productivity of livestock. Macrocyclic lactones (MLs) are the most common class of chemicals used in helminth control programs, however, their intense use is accelerating the development of parasite resistance. For cattle, little is known regarding the relationship between fecal egg counts (FECs) and the helminth population inside the animal's gastrointestinal tract and so this study evaluated the correlation between FEC and worm burden in cattle treated or not with MLs (ivermectin 200 µg/kg, ivermectin 630 µg/kg, abamectin 200 µg/kg, doramectin 700 µg/kg and moxidectin 200 µg/kg). Animals were necropsied to determine if there were any modifications to the proportions of worm species due to chemical treatment. FECs of ML-treated and untreated animals showed significant (p ≤ 0.05 and R2 ≥0.70) positive linear correlations and substantial or perfect strength-of-agreement (LCCC ≥ 0.61) with total worms present, all of which were Haemonchus placei and Cooperia punctata. However, this correlation and strength-of-agreement did not occur when the efficacy of MLs was ≥80 % against these helminths. Among the active MLs tested, moxidectin had the weakest relationship between FEC and worm burden, except for H. placei. Analysis of the helminthological fauna found an increase of H. placei (35.6 % = 95 % CI 35.4-35.6) and a consequent decrease of C. punctata (52.5 % = 95 % CI 52.3-52.6) in untreated animals, when compared to studies carried out over 20-40 years ago, but this proportion was reversed for ML-treated animals (C. punctata 64.5 % = 95 % CI 64.4-64.8; H. placei 30.8 % = 95 % CI 30.6-30.8). It is possible that MLs mitigate this effect in the field and that C. punctata remained prevalent in cattle in different regions of Brazil.

Ivermectin: A multilevel approach to evaluate effects in Prochilodus lineatus (Valenciennes, 1836) (Characiformes, Prochilodontidae), an inland fishery species.

Ivermectin (IVM) is one of the most widely used antiparasitics worldwide. It is a potent and effective drug for treatment and prevention of internal and external parasitic infections of livestock and humans. IVM is excreted unchanged in manure of treated animals. Thus, residues of IVM may reach aquatic systems, affecting non-target organisms such as fish. Although the presence of IVM in aquatic environments has been reported, a multilevel approach (from cellular to behavioral responses) is necessary to determine the health of exposed organisms and the environmental risks associated. The aim of the present study was to investigate the response of the Neotropical fish Prochilodus lineatus, one of the main target species of South American freshwater fisheries, exposed to environmental concentrations of IVM: low (0.5 µg L-1) and high (1.5 µg L-1). Behavioral responses were assessed in juvenile fish and included water column use, routine swimming, total distance travelled, total activity time and Maximum swimming speed achieved during the escape response. Biochemical/oxidative stress responses assessed included brain acetylcholinesterase (AChE), catalase (CAT) and glutathione S-transferase (GST) activities; total antioxidant competence against peroxyl radicals (ACAP) and lipid oxidative damage (TBARs). Hematological biomarker responses included blood glucose levels, hematocrit, hemoglobin concentration, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and mean corpuscular volume. Condition factor and hepatosomatic index were also calculated. The lowest IVM concentration caused a significant decrease in GST activity and maximum swimming speed during the escape response. Multivariate analysis with biochemical/stress and behavioral data revealed overall effects of IVM treatments. This multilevel analysis shows detrimental effects related to swimming behavior and predator avoidance which could affect population size and size-structure of P. lineatus. To our knowledge this is the first attempt to assess the effects of IVM on Neotropical fishes using an integrative approach based on biomarkers from different levels of biological organization.

Aerobic dissipation of avermectins and moxidectin in subtropical soils and dissipation of abamectin in a field study.

Avermectins and moxidectin are antiparasitics widely used as active pharmaceutical ingredients in veterinary medicine, as well as in pesticide formulations for pest control in agriculture. Although the use of these compounds provides benefits to agribusiness, they can impact the environment, since a large part of these substances may reach the soil and water from the excreta of treated animals and following direct applications to crops. The present work had the objective of evaluating the dissipation behaviors of abamectin, doramectin, eprinomectin, ivermectin, and moxidectin in four native Brazilian soils of different textural classes (clay, sandy-clay, sandy, and sandy-clay-loam), following OECD Guideline 307. The studies were conducted in a climate chamber at 22 °C, 71% relative humidity, and protected from light. The dissipation studies were carried out with all drugs together, since no difference was verified when studies were done with each drug separately. The concentrations of the drugs in the soils were determined using an ultra-high performance liquid chromatograph coupled to a fluorescence detector or a tandem mass spectrometer. The dissipation half-life (DT50) values ranged from 9 to 16 days and the calculated GUS index values were in the range from -1.10 to 0.08, indicating low mobility of the drugs in the soils evaluated and low tendency for leaching. In addition, a field study was carried out to evaluate the dissipation of abamectin after application of a foliar pesticide in an orange crop. A DT50 of 9 days was determined, which was similar to that obtained under controlled conditions in the climate chamber (12 days), indicating that biotransformation was the primary process influencing the overall dissipation.

Therapeutical doses of ivermectin and its association with stress disrupt motor and social behaviors of juvenile rats and serotonergic and dopaminergic systems.

Ivermectin is a human and veterinary antiparasitic drug which is one of the most widely used in the world. Studies from our group have revealed several behavioral and neurochemical impairments induced by therapeutic doses of ivermectin in adult rats. However, the effects on juveniles remain unknown. Ivermectin has been prescribed for juvenile humans, pets and farm animals, which still show remarkable development and postnatal maturation and may be more susceptible to drug interventions. Hence, we studied the behavioral and neurochemical effects of two therapeutical doses (0.2 and 1.0 mg/kg) of ivermectin in juvenile rats. As it is underestimated in prescriptions, the stress factor was also studied. Ivermectin 1.0 mg/kg induced hyperlocomotion in juvenile rats. Association of 1.0 mg/kg ivermectin with stress induced hypolocomotion in rats. Ivermectin 1.0 mg/kg whether or not associated with stress exacerbated socialization of rats. Ivermectin did not induce anxiety-like behavior neither affected corticosterone levels of juvenile rats. The motor/exploratory behavioral findings induced by association of ivermectin and stress seem to be triggered after the increase in the striatal serotonergic system activity. Association of ivermectin with stress increased striatal dopamine levels, which increased (excessive) social play behavior. Our results suggest a review of the prescribed dose of ivermectin for juvenile humans and pets. Moreover, the stress factor should be considered for ivermectin medical prescriptions, since it may exacerbate behavioral and neurochemical disturbances.

Avaliação da atividade da enzima glutationa-s-transferase da minhoca Eisenia foetida exposta à ivermectina / Evaluation of glutatione-s-transferase enzyme activity of the earthworm Eisenia foetida exposed to ivermectin

Muitos tipos de drogas são usados na medicina veterinária para controlar e melhorar a saúde animal através de tratamentos terapêuticos e profiláticos. A desvantagem desta prática é que os produtos farmacêuticos e seus metabólitos são liberados no ambiente e podem influenciar a fauna do solo através da excreção do esterco ou pela posterior aplicação ao campo agrícola. As avermectinas são vastamente utilizadas na medicina veterinária e na agricultura. Estudos anteriores demonstraram que a ivermectina (IVM), um parasiticida amplamente utilizado, é muito tóxico para diversas espécies de invertebrados não-alvo. Tendo em vista que a IVM é pouco metabolizada, excretada de forma relativamente inalterada e pela escassez de dados sobre a toxicidade aos invertebrados do solo, foram investigados, neste estudo, os efeitos agudos e crônicos deste parasiticida sobre a glutationa-s -transferase (GST) da oligoqueta Eisenia foetida. As minhocas Eisenia foetida foram expostas à concentrações de IVM a 0, 1, 5, 10, 50 e 100 mg kg-1, e as amostras foram tomadas nos dias 7, 14 e 28 para determinação da atividade da GST. Os resultados mostraram que a duração da exposição alterou significativamente os efeitos do parasiticida investigado sobre a atividade de GST. Especificamente, após uma redução inicial, o prolongamento da exposição causou a indução da atividade da GST. Com o aumento da concentração de IVM, as atividades da GST foram inibidas significativamente após 7 dias de exposição. Em particular, o efeito inibitório foi significativo nas concentrações mais elevadas de tratamento (10, 50 e 100 mg kg-1). Por outro lado, aos 14 e 28 dias foram observadas induções na atividade da enzima. A atividade da GST pode ser considerada como parâmetro sensível para avaliar a toxicidade da ivermectina para minhocas.

Many types of drugs are used in veterinary medicine to control and improve animal health through therapeutic and prophylactic treatments. The disadvantage of this practice is that pharmaceuticals and their metabolites are released into the environment and may influence soil fauna through manure excretion and subsequent application to agricultural field. The avermectins are extensively and increasingly used in veterinary medicine and agriculture. Previous studies have shown that ivermectin (IVM), a widely used parasiticide, is very toxic to many non-target invertebrate species. In view of the little metabolism and most of the ivermectin dose given to the animal is excreted, relatively unaltered, primarily in the feces and the scarcity of data on toxicity to soil invertebrates, acute and chronic effects of the parasiticide on the glutatione-s-transferase (GST) of the oligochaete Eisenia foetida were investigated. Earthworms of Eisenia foetida were exposed to IVM at 0, 1, 5, 10, 50 and 100 mg kg-1 concentrations; samples were taken at days 7, 14, and 28 exposure for determination of GST activities. The results showed that duration of the exposure significantly changed the effects of the investigated parasiticide on the GST activity. Namely, after the initial decrease, the prolongation of exposure caused the induction of the GST activity. With increasing IVM concentration, GST activities were inhibited significantly after 7 days of the exposure. In particular, the inhibition effect was significant at the higher treatment levels (10, 50 and 100 mg kg-1). On the other hand, at 14 and 28 days were observed inductions of enzyme activity. GST activity can be regarded as sensitive parameter for evaluating the toxicity of ivermectin to earthworms.

Pipette-tip solid-phase extraction using poly(1-vinylimidazole-co-trimethylolpropane trimethacrylate) as a new molecularly imprinted polymer in the determination of avermectins and milbemycins in fruit juice and water samples.

A simple HPLC method was developed for the determination of abamectin (ABA), eprinomectin (EPR), and moxidectin (MOX). Pipette-tip molecularly imprinted polymer solid-phase extraction (PT-MIP-SPE) using poly(1-vinylimidazole-co-trimethylolpropane trimethacrylate) as a selective adsorbent material was studied in detail, including the washing solvent, type and volume of eluent, pH, quantity of adsorbent material and sample volume. The performance criteria for linearity, sensitivity, precision, accuracy, recovery, robustness and stability have been assessed and were within the recommended guidelines. The mean extraction recoveries/relative standard deviation for ABA 1b, EPR, ABA 1a and MOX were 98.77 ±â€¯3.82%, 88.19 ±â€¯2.57%, 110.54 ±â€¯1.52% and 100.42 ±â€¯0.59%, respectively. Finally, the results proved that PT-MIP-SPE coupled to HPLC-UV is an economical, simple and easy-to-perform technique, and presented a high potential for extraction of macrocyclic lactones in mineral water and grape and juice samples.

Pipette-tip solid-phase extraction using polypyrrole as efficient adsorbent for extraction of avermectins and milbemycins in milk.

In this work, we developed a HPLC method for the multidetermination of avermectins (AVM) (abamectin-ABA 1b and ABA 1a, eprinomectin-EPR, and ivermectin-IVM) and milbemycins (moxidectin-MOX) in milk samples using polypyrrole (PPy) as adsorbent material in pipette-tip solid-phase extraction (PT-PPy-SPE). PPy was characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray diffraction and the data agreed with the literature. The sample preparation included the clean-up of the milk by protein precipitation (PP) with acetonitrile and extraction of the analytes by PT-PPy-SPE. The chromatographic method was developed in reverse phase and isocratic mode with flow rate at 1.2 mL min-1 and ultraviolet detection at 250 nm. The mobile phase composition was acetonitrile:methanol:water (55:25:20, v/v/v). The studied parameters and the optimized conditions for the sample preparation were washing solvent (300 µL water), volume and type of eluent (500 µL methanol), volume and pH of sample (1 mL and pH 10), amount of adsorbent material (50 mg PPy), and without addition of salt (NaCl). The method was linear over the concentration range from 20 to 3000 ng mL-1 with coefficients of correlation (r) ≥ 0.99 for all analytes and recoveries around 100%. The method developed and validated was used for the analyses of real milk samples from cow treated with Ivomec® (IVM 3.5%), in which were found 21.51 ± 2.94 ng mL-1 of IVM. Finally, the results proved that PT-PPy-SPE coupled to HPLC-UV was economical, simple, and easy-to-perform technique. Graphical abstract Pipette-tip solid phase extraction using polypirrole as adsorbent material for determination of avermectins and milbemycins in milk.

Ivermectin reduces sexual dimorphism in behavioral models of exploration, anxiety and depression in C57BL/6 mice / A ivermectina reduz o dimorfismo sexual em modelos comportamentais de exploração, ansiedade e depressão de camundongos C57BL/6

Avermectins and milbemycins, often also referred as macrocyclic lactones, are the most used antiparasitic medicines in the world and are widely employed in veterinary medicine, agriculture and human medicine. The objective of this work was to evaluate the sexually dimorphic effects of ivermectin (IVM) in C57BL/6 mice in animal models linked to emotionality. For this, male and female mice were treated with two therapeutic doses of IVM (0.2 or 1.0 mg / kg) or 0.9% saline solution. Twenty-four hours after treatments the mice were observed in open field, elevated plus maze and tail suspension test. The results showed that, in relation to the male mice: 1) ivermectin, in both doses, prevented the sexual dimorphism in the frequency of locomotion and reduced, in females, the frequency of rearing and the time of immobility; 2) in the elevated plus maze, females showed increase in the open arm time and in risk behavior and reduction in the frequency of entries in the closed arm; 3) in the tail suspension test, IVM prevented the expression of sexual dimorphism. It was concluded that in the open field, elevated plus maze and tail suspension ivermectin produces sexually dimorphic effects in C57BL/6 mice. The most prominent effects of ivermectin occurred in females.(AU)

As avermectinas e as milbemicinas, muitas vezes também referidas como lactonas macrocíclicas, são os medicamentos antiparasitários mais vendidos no mundo, sendo amplamente utilizados na medicina veterinária, na agricultura e em medicina humana. O objetivo deste trabalho foi o de avaliar os efeitos sexualmente dimórficos da ivermectina (IVM) em camundongos C57BL/6 em modelos animais ligados à emocionalidade. Para tanto, os camundongos machos e fêmeas foram tratados com duas doses terapêuticas da IVM (0,2 ou 1,0 mg/kg) ou solução salina a 0,9%. Vinte e quatro horas após estes tratamentos, foram observados em campo aberto, no labirinto em cruz elevada e no teste de suspensão da cauda. Os resultados mostraram que, em relação aos camundongos machos: 1) a ivermectina, nas duas doses, impediu o dimorfismo sexual na frequência de locomoção e reduziu, em fêmeas, a frequência de levantar e o tempo de imobilidade; 2) no labirinto em cruz elevada, as fêmeas mostraram aumento no tempo de braço aberto e no comportamento de risco e redução na frequência de entradas no braço fechado; 3) no teste de suspensão da cauda a ivermectina impediu a expressão do dimorfismo sexual. Concluiu-se que, nos modelos atividade geral em campo aberto, labirinto em cruz elevada e suspensão da cauda, a ivermectina produz efeitos sexualmente dimórficos em camundongos C57BL/6. Os efeitos mais proeminentes da ivermectina ocorreram em fêmeas.(AU)

Ivermectin reduces sexual dimorphism in behavioral models of exploration, anxiety and depression in C57BL/6 mice / A ivermectina reduz o dimorfismo sexual em modelos comportamentais de exploração, ansiedade e depressão de camundongos C57BL/6

Avermectins and milbemycins, often also referred as macrocyclic lactones, are the most used antiparasitic medicines in the world and are widely employed in veterinary medicine, agriculture and human medicine. The objective of this work was to evaluate the sexually dimorphic effects of ivermectin (IVM) in C57BL/6 mice in animal models linked to emotionality. For this, male and female mice were treated with two therapeutic doses of IVM (0.2 or 1.0 mg / kg) or 0.9% saline solution. Twenty-four hours after treatments the mice were observed in open field, elevated plus maze and tail suspension test. The results showed that, in relation to the male mice: 1) ivermectin, in both doses, prevented the sexual dimorphism in the frequency of locomotion and reduced, in females, the frequency of rearing and the time of immobility; 2) in the elevated plus maze, females showed increase in the open arm time and in risk behavior and reduction in the frequency of entries in the closed arm; 3) in the tail suspension test, IVM prevented the expression of sexual dimorphism. It was concluded that in the open field, elevated plus maze and tail suspension ivermectin produces sexually dimorphic effects in C57BL/6 mice. The most prominent effects of ivermectin occurred in females.

As avermectinas e as milbemicinas, muitas vezes também referidas como lactonas macrocíclicas, são os medicamentos antiparasitários mais vendidos no mundo, sendo amplamente utilizados na medicina veterinária, na agricultura e em medicina humana. O objetivo deste trabalho foi o de avaliar os efeitos sexualmente dimórficos da ivermectina (IVM) em camundongos C57BL/6 em modelos animais ligados à emocionalidade. Para tanto, os camundongos machos e fêmeas foram tratados com duas doses terapêuticas da IVM (0,2 ou 1,0 mg/kg) ou solução salina a 0,9%. Vinte e quatro horas após estes tratamentos, foram observados em campo aberto, no labirinto em cruz elevada e no teste de suspensão da cauda. Os resultados mostraram que, em relação aos camundongos machos: 1) a ivermectina, nas duas doses, impediu o dimorfismo sexual na frequência de locomoção e reduziu, em fêmeas, a frequência de levantar e o tempo de imobilidade; 2) no labirinto em cruz elevada, as fêmeas mostraram aumento no tempo de braço aberto e no comportamento de risco e redução na frequência de entradas no braço fechado; 3) no teste de suspensão da cauda a ivermectina impediu a expressão do dimorfismo sexual. Concluiu-se que, nos modelos atividade geral em campo aberto, labirinto em cruz elevada e suspensão da cauda, a ivermectina produz efeitos sexualmente dimórficos em camundongos C57BL/6. Os efeitos mais proeminentes da ivermectina ocorreram em fêmeas.

Multiresidue method for identification and quantification of avermectins, benzimidazoles and nitroimidazoles residues in bovine muscle tissue by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) using a QuEChERS approach.

A quantitative and confirmatory multiresidue method for determining the presence of avermectins, benzimidazoles and nitroimidazoles in bovine muscle tissue by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was developed, optimized and validated, using a QuEChERS extraction. The evaluated performance parameters were linearity, selectivity, matrix effect, decision limits (CCα), detection capability (CCß), limits of detection (LOD), limits of quantification (LOQ), accuracy, precision and robustness. The validated method exhibited linearity with coefficient of determination (R2) higher than 0.90 in the working range from 0.5 to 2.0 times the maximum residue limit (MRL) or the minimum required performance level (MRPL) for the studied analytes, except for closantel, for which the linear study range was defined from 50 to 200µgkg-1. The method was selective in the presence of macrolides and lincosamides for all the studied analytes. The LOD varied from 0.007 to 66.715µgkg-1, whereas LOQ values ranging from 0.011 to 113.674µgkg-1 were found. The results of the evaluation of the accuracy and precision were satisfactory for all the studied analytes, and according to the assessment of the robustness, the method was not robust only for the analytes abamectin, moxidectin, doramectin fenbendazole sulfone, closantel, thiabendazole, hydroxyl-metronidazole and ronidazole. The performance parameters demonstrated total method adequacy for the detection and quantification of avermectins, benzimidazoles and nitroimidazoles residues in bovine muscle tissues.

Efficacy of oral doramectin as treatment for Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits / Eficácia de doramectin no tratamento oral para Psoroptes ovis e Leporacarus gibbus em coelhos naturalmente infestados

The present study evaluated the efficacy of a single oral dose of doramectin in the control of Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits. Sixteen adult rabbits were selected and distributed in two experimental groups. The treated group received 200 µg/Kg of oral doramectin and the control group received the same volume of saline solution. The diagnosis of the mites was made with a stereoscopic microscope. Hairs from the dorsal part of the neck, lumbar right, lumbar left, ventral side of the tail and ventral abdomen were evaluated for L. gibbus, and ear wax evaluated for P. ovis. The evaluation of the efficiency and the clinical assessment of the lesions was made in days 0, +3, +7, +14, +21, +28, and +35 after treatment. An efficacy of 75% and 87,5% was observed for L. gibbus in days +3 and +7 after treatment, an efficacy of 100% was observed in days +14, + 21, +28 e +35. An efficacy of 100% for the control of P. ovis was observed following day +7. The clinical lesion score of the control group remained unaltered, except for one animal which conditions worsened during experimentation. In the treated group animals, regression of the lesions was observed following day +3, and on day +21 no signal of infestation by P. ovis was present. None of the animals from the treated group presented secondary collateral effects caused by the doramectin, which proved itself as an optimal alternative for mite control in naturally infested rabbits.(AU)

O objetivo do trabalho foi avaliar a eficácia da doramectina administrada por via oral no controle de Psoroptes ovis e Leporacarus gibbus em coelhos naturalmente infestados. Foram selecionados 16 coelhos adultos, distribuídos em dois grupos experimentais, compondo oito animais por grupo. O grupo tratado foi medicado com 200µg/kg de doramectina por via oral, enquanto que no grupo controle foi administrado o mesmo volume de solução salina. O diagnóstico dos ácaros foi realizado com auxílio de microscópio estereoscópico. Foram coletados pelos das regiões do pescoço dorsal, lombar direita, lombar esquerda, cauda ventral e abdômen ventral para avaliação de L. gibbus e para P. ovis foi coletado cerúmen das orelhas com auxílio de zaragatoas. A avaliação da eficácia e a avaliação clínica das lesões, mensuradas em escores (grau 0 a 4), foi realizada nos dias 0, +3, +7, +14, +21, +28 e +35, após o tratamento. Foi observada eficácia de 75% e 87,5% no controle de L. gibbus nos dias +3 e +7 após o tratamento, sendo observada eficácia de 100% nos dias +14, + 21, +28 e +35. Foi observada eficácia de 100% no controle de P. ovis a partir do dia +7, permanecendo até o final do período observacional. O escore das lesões clínicas no grupo controle permaneceu de forma inalterada, exceto em um animal que piorou ao longo dos dias experimentais, enquanto nos animais do grupo tratado regrediu a partir do dia +3 e já no dia +21 após o tratamento, os animais apresentavam-se sem sinais da infestação por P. ovis. Nenhum animal do grupo tratado apresentou quaisquer efeitos colaterais secundários causados pela doramectina, que se mostrou uma ótima alternativa para o controle dos ácaros em coelhos naturalmente parasitados.(AU)

Efficacy of oral doramectin as treatment for Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits / Eficácia de doramectin no tratamento oral para Psoroptes ovis e Leporacarus gibbus em coelhos naturalmente infestados

The present study evaluated the efficacy of a single oral dose of doramectin in the control of Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits. Sixteen adult rabbits were selected and distributed in two experimental groups. The treated group received 200 g/Kg of oral doramectin and the control group received the same volume of saline solution. The diagnosis of the mites was made with a stereoscopic microscope. Hairs from the dorsal part of the neck, lumbar right, lumbar left, ventral side of the tail and ventral abdomen were evaluated for L. gibbus, and ear wax evaluated for P. ovis. The evaluation of the efficiency and the clinical assessment of the lesions was made in days 0, +3, +7, +14, +21, +28, and +35 after treatment. An efficacy of 75% and 87,5% was observed for L. gibbus in days +3 and +7 after treatment, an efficacy of 100% was observed in days +14, + 21, +28 e +35. An efficacy of 100% for the control of P. ovis was observed following day +7. The clinical lesion score of the control group remained unaltered, except for one animal which conditions worsened during experimentation. In the treated group animals, regression of the lesions was observed following day +3, and on day +21 no signal of infestation by P. ovis was present. None of the animals from the treated group presented secondary collateral effects caused by the doramectin, which proved itself as an optimal alternative for mite control in naturally infested rabbits.(AU)

O objetivo do trabalho foi avaliar a eficácia da doramectina administrada por via oral no controle de Psoroptes ovis e Leporacarus gibbus em coelhos naturalmente infestados. Foram selecionados 16 coelhos adultos, distribuídos em dois grupos experimentais, compondo oito animais por grupo. O grupo tratado foi medicado com 200g/kg de doramectina por via oral, enquanto que no grupo controle foi administrado o mesmo volume de solução salina. O diagnóstico dos ácaros foi realizado com auxílio de microscópio estereoscópico. Foram coletados pelos das regiões do pescoço dorsal, lombar direita, lombar esquerda, cauda ventral e abdômen ventral para avaliação de L. gibbus e para P. ovis foi coletado cerúmen das orelhas com auxílio de zaragatoas. A avaliação da eficácia e a avaliação clínica das lesões, mensuradas em escores (grau 0 a 4), foi realizada nos dias 0, +3, +7, +14, +21, +28 e +35, após o tratamento. Foi observada eficácia de 75% e 87,5% no controle de L. gibbus nos dias +3 e +7 após o tratamento, sendo observada eficácia de 100% nos dias +14, + 21, +28 e +35. Foi observada eficácia de 100% no controle de P. ovis a partir do dia +7, permanecendo até o final do período observacional. O escore das lesões clínicas no grupo controle permaneceu de forma inalterada, exceto em um animal que piorou ao longo dos dias experimentais, enquanto nos animais do grupo tratado regrediu a partir do dia +3 e já no dia +21 após o tratamento, os animais apresentavam-se sem sinais da infestação por P. ovis. Nenhum animal do grupo tratado apresentou quaisquer efeitos colaterais secundários causados pela doramectina, que se mostrou uma ótima alternativa para o controle dos ácaros em coelhos naturalmente parasitados.(AU)

Efficacy of oral doramectin as treatment for Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits

ABSTRACT: The present study evaluated the efficacy of a single oral dose of doramectin in the control of Psoroptes ovis and Leporacarus gibbus in naturally infested rabbits. Sixteen adult rabbits were selected and distributed in two experimental groups. The treated group received 200 g/Kg of oral doramectin and the control group received the same volume of saline solution. The diagnosis of the mites was made with a stereoscopic microscope. Hairs from the dorsal part of the neck, lumbar right, lumbar left, ventral side of the tail and ventral abdomen were evaluated for L. gibbus, and ear wax evaluated for P. ovis. The evaluation of the efficiency and the clinical assessment of the lesions was made in days 0, +3, +7, +14, +21, +28, and +35 after treatment. An efficacy of 75% and 87,5% was observed for L. gibbus in days +3 and +7 after treatment, an efficacy of 100% was observed in days +14, + 21, +28 e +35. An efficacy of 100% for the control of P. ovis was observed following day +7. The clinical lesion score of the control group remained unaltered, except for one animal which conditions worsened during experimentation. In the treated group animals, regression of the lesions was observed following day +3, and on day +21 no signal of infestation by P. ovis was present. None of the animals from the treated group presented secondary collateral effects caused by the doramectin, which proved itself as an optimal alternative for mite control in naturally infested rabbits.

RESUMO: O objetivo do trabalho foi avaliar a eficácia da doramectina administrada por via oral no controle de Psoroptes ovis e Leporacarus gibbus em coelhos naturalmente infestados. Foram selecionados 16 coelhos adultos, distribuídos em dois grupos experimentais, compondo oito animais por grupo. O grupo tratado foi medicado com 200g/kg de doramectina por via oral, enquanto que no grupo controle foi administrado o mesmo volume de solução salina. O diagnóstico dos ácaros foi realizado com auxílio de microscópio estereoscópico. Foram coletados pelos das regiões do pescoço dorsal, lombar direita, lombar esquerda, cauda ventral e abdômen ventral para avaliação de L. gibbus e para P. ovis foi coletado cerúmen das orelhas com auxílio de zaragatoas. A avaliação da eficácia e a avaliação clínica das lesões, mensuradas em escores (grau 0 a 4), foi realizada nos dias 0, +3, +7, +14, +21, +28 e +35, após o tratamento. Foi observada eficácia de 75% e 87,5% no controle de L. gibbus nos dias +3 e +7 após o tratamento, sendo observada eficácia de 100% nos dias +14, + 21, +28 e +35. Foi observada eficácia de 100% no controle de P. ovis a partir do dia +7, permanecendo até o final do período observacional. O escore das lesões clínicas no grupo controle permaneceu de forma inalterada, exceto em um animal que piorou ao longo dos dias experimentais, enquanto nos animais do grupo tratado regrediu a partir do dia +3 e já no dia +21 após o tratamento, os animais apresentavam-se sem sinais da infestação por P. ovis. Nenhum animal do grupo tratado apresentou quaisquer efeitos colaterais secundários causados pela doramectina, que se mostrou uma ótima alternativa para o controle dos ácaros em coelhos naturalmente parasitados.

On-line solid-phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry for the determination of avermectins and milbemycin in soils.

Avermectins and milbemycin are widely used as veterinary drugs and as agricultural pesticides, and their residues have been detected in soil. This study reports a simple and high-throughput method for determining ivermectin (IVER), abamectin (ABA), doramectin (DORA), eprinomectin (EPRI), and moxidectin (MOXI) residues in soils, employing an on-line solid-phase extraction technique coupled with ultra-high performance liquid chromatography and tandem mass spectrometry (SPE-UHPLC-MS/MS). The method was validated and applied for the determination of ABA in soils from an orange plantation treated with this pesticide. The sample preparation procedure consisted of extraction of the compounds from soil using methanol (with recoveries of 73-85%), and subsequent on-line SPE cleanup and concentration using a C8 sorbent coupled to the UHPLC-MS/MS system. The optimal conditions were: water:methanol (40:60, v/v) sample solvent; water:methanol (96:4, v/v) loading solvent; 2×250µL sample volume; and elution of the analytes retained on the SPE column in back flush with 5mmolL-1 ammonium acetate:acetonitrile (10:90, v/v) chromatographic mobile phase. The method produced linear results in the ranges 0.1-10ngg-1 (IVER, ABA, DORA, and MOXI) and 0.5-10ngg-1 (EPRI), with linearity greater than 0.99. The precision of the method was better than 19% and accuracy was in the range 74-89%. The limits of quantitation were 0.2ngg-1 for EPRI and 0.1ngg-1 for the other compounds. The SPE column could be reused in more than 2000 analyses without loss of efficiency. The ABA concentration in the soil varied between 1.7 and 18ngg-1, and no dissipation was observed during five consecutive days after application of the pesticide to the orange plantation.

Development, validation, and application of a method for selected avermectin determination in rural waters using high performance liquid chromatography and fluorescence detection.

Avermectins (AVM) are macrocyclic lactones used in livestock and agriculture. A quantitative method of high performance liquid chromatography with fluorescence detection for the determination of eprinomectin, abamectin, doramectin and ivermectin in rural water samples was developed and validated. The method was employed to study samples collected in the Pito Aceso River microbasin, located in the Bom Jardim municipality, Rio de Janeiro State, Brazil. Samples were extracted by solid phase extraction using a polymeric stationary phase, the eluted fraction was re-concentrated under a gentle N2 flow and derivatized to allow AVM determination using liquid chromatography with fluorescence detection. The excitation and emission wavelengths of the derivatives were 365 and 470nm, respectively, and a total chromatographic run of 12min was achieved. Very low limits of quantification (22-58ngL(-1)) were found after re-concentration using N2. Recovery values varied from 85.7% to 119.2% with standard deviations between 1.2% and 10.2%. The validated method was applied in the determination of AVM in 15 water samples collected in the Pito Aceso River microbasin, but most of them were free of AVM or showed only trace levels of these compounds, except for a sample that contained doramectin (9.11µgL(-1)). The method is suitable for routine analysis with satisfactory recovery, sensitivity, and selectivity.