Avaliação dos efeitos de princípios fitoterápicos e homeopáticos no controle de Rhipicephalus (Boophilus) microplus e comparação de técnicas para estimativa de eclosão de larvas in vitro
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Data
2017-02-24
Autores
Figueiredo, Amanda [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O parasitismo por Rhipicephalus (Boophilus) microplus ocasiona grandes perdas econômicas nos rebanhos bovinos, e seu controle por meio de carrapaticidas sintéticos enfrenta problemas de resistência, além do risco de resíduos nos alimentos e ambiente. Com o objetivo de contribuir com informações relevantes para o controle desse parasita, o presente estudo teve três objetivos: 1) avaliar in vitro o efeito do óleo essencial de Ocotea elegans “canela-sassafrás” sobre larvas e fêmeas ingurgitadas de R. (B.) microplus; 2) avaliar medicamento homeopático no controle de infestações naturais; 3) comparar as técnicas de estimativa visual e de quantificação por amostragem de larvas eclodidas no teste de imersão de fêmeas adultas, visto a importância dessas no levantamento de substâncias com ação carrapaticida. No primeiro experimento “Efeito acaricida e repelente in vitro do óleo essencial de Ocotea elegans (canela-sassafrás) sobre Rhipicephalus (Boophilus) microplus”, foram adotados os testes: contato de larvas em papel impregnado (LPI), teste de repelência larvar (TR) e imersão de fêmeas adultas (AIT). A fim de verificar a eficácia, O. elegans foi avaliada nas concentrações de 0,78 mg/mL a 100 mg/mL. No AIT, a partir da concentração de 25 mg/mL, a eficácia foi superior a 90%. Os LPI (48h) a 100 mg/mL resultaram em taxas de mortalidade acima de 70%. Já o TR obteve repelência superior a 80% a partir da menor concentração avaliada. Em relação às concentrações letais (CL), a menor CL50 obtida no LPI foi de 25,59 mg/mL 48h pós tratamento. As CL50 e CL90 no AIT foram de 4,96 e 17,37 mg/mL e no TR de 0,04 e 1,24 mg/mL, respectivamente. Foi possível concluir que O. elegans demonstrou efeito significativo sobre fêmeas ingurgitadas e de repelência das larvas, e possivelmente pode ser um adjuvante no controle do carrapato bovino, devendo-se priorizar testes in vivo. No segundo experimento, “Estudo da homeopatia no controle de infestações naturais por R. (B.) microplus em bovinos de leite”, 24 fêmeas da raça Holandesa e Jersey x Holandesa foram divididas nos grupos controle (placebo) (n=12) e tratado (bioterápico 30 CH + Sulphur 30 CH) (n=12), administrado no concentrado (2kg/animal/dia) por 12 meses. De cada grupo coletou-se fêmeas ingurgitadas, a fim de comparar os parâmetros reprodutivos, e semi-ingurgitadas para avaliações morfo-histológicas dos ovários. Mensurou-se o peso vivo (PV), volume globular (VG) e realizou-se contagens de fêmeas ingurgitadas no corpo dos animais. Os resultados médios de PV, VG e n° de carrapatos não foram diferentes estatisticamente para os grupos controle e homeopatia: 616,5 kg e 618,6 kg, 27,9% e 27,3%, 12,19 e 13,58 carrapatos, respectivamente. Nas análises in vitro, as médias do peso das fêmeas (0,18 e 0,17 g), peso dos ovos (0,07 e 0,06 g), % de eclosão de larvas (70,1 e 76,6%) e índice de eficiência reprodutiva (54,3 e 60,6%), para os grupos controle e homeopatia, respectivamente, também não tiveram diferença estatística. Além disso, nenhuma alteração nos ovários foi observada nos estudos em foto-microscopia. Portanto, o medicamento homeopático avaliado não foi eficaz no controle de R. (B.) microplus e não interferiu nos parâmetros reprodutivos das fêmeas ingurgitadas. Finalmente, no estudo “Alternative methods for egg hatch evaluation of Rhipicephalus (Boophilus) microplus” em que comparou-se duas técnicas de estimativa de eclosão de ovos, fêmeas ingurgitadas coletadas de bovinos foram submetidas ao AIT com extratos vegetais e mantidas em incubadora para realizar a oviposição. Os ovos foram transferidos para seringas e incubados por 15 dias. A eclosão dos ovos foi avaliada em 210 seringas por estimativa visual (%) e também contadas até 100, em três repetições. Foram encontradas diferenças significativas entre os dois testes. Na estimativa visual (56,8%) a porcentagem de eclosão média foi maior do que na quantificação por amostragem (48,0%). Na quantificação por amostragem, não foram observadas diferenças estatísticas nas contagens das três amostras (48,1, 47,8 e 48,1%) e a correlação entre as repetições foi de 0,96, sugerindo que a contagem de uma amostra é suficiente e o resultado independente do avaliador. O presente estudo contribuiu com informações inéditas sobre o potencial acaricida e repelente de O. elegans. Discutiu-se que apesar do medicamento homeopático não ter tido efeito, tal conclusão não pode ser estendida a outras formulações homeopáticas, vias de aplicação e condições de manejo adversas às do presente estudo. Por fim, os resultados do estudo comparativo contribuem para o aperfeiçoamento do AIT e podem estimular os pesquisadores a optar por técnicas mais confiáveis na avaliação da eclosão de ovos.
The parasitism by Rhipicephalus (Boophilus) microplus causes large economic loss in cattle herds and its control through chemical acaricides faces problems of resistance and residues in food and in the environment. Aiming to contribute with relevant information for the control of this parasite, the present study had three objectives: 1) evaluate the effect in vitro of Ocotea elegans essential oil on larvae and engorged females of R. (B.) microplus, 2) evaluate homeopathic medicine to control R. (B.) microplus natural infestations, and 3) compare visual estimation and quantification by sampling techniques of larvae hatching in the engorged females immersion test, due to the importance of this technique in the screening of substances with antiparasitic action. In the first experiment, "In vitro acaricidal and repellent effect of Ocotea elegans essential oil on R. (B.) microplus", were adopted the tests: larval packet test (LPT), the larval repellency test (RT) and the adult immersion test (AIT). In order to verify efficacy, O. elegans was evaluated at concentrations of 0.78 mg/mL to 100 mg/mL. In the AIT, from the concentration of 25 mg/ml, the efficacies were higher than 90%. LPT (48h) at 100 mg/mL resulted in mortality rates higher than 70%. The RT obtained repellency higher than 80% sice the lowest concentration evaluated. In relation to the lethal concentrations, the lowest LC50 obtained in the LPT was 25.59 mg/mL, 48 hours post treatment. The LC50 and LC90 in the AIT were 4.96 and 17.37 mg/mL and in TR were 0.04 and 1.24 mg/mL, respectively. It was possible to conclude that O. elegans had significant effect in engorged females and larvae repellency and may be in the future an adjuvant for tick control, prioritizing in vivo tests. In the second experiment, “Study of homeopathy in the control of natural infestation of R. (B.) microplus in dairy cattle”, 24 females of the Dutch and Jersey x Dutch breed were divided in the control group (placebo) and treated (biotherapic 30 CH + Sulphur 30 CH) (n=12), administered in the concentrate at 2 kg/animal/day for 12 months. It was collected in each group engorged females to compare the reproductive parameters, and semi-engorged females for the ovaries histologic evaluation. The live weight (LW), packed cell volume (PCV) and counts of engorged females in the animals’ body were held. The average results of LW, PCV and ticks were not statistically different in the control and homeopathic groups: 616.5 kg and 618.6 kg, 27.9% and 27.3%, 12.19 and 13.58 ticks, respectively. In the in vitro analyzes, the average weight of females (0.18 and 0.17 g), egg weight (0.07 and 0.06 g), larvae hatching % (70.1 and 76.6%) and reproductive efficiency index (54.3 and 60.6%), to control and homeopatic groups, respectively, had no statistical difference as well. In addition, no changes in the ovaries were observed in microscopy. Therefore, the homeopathic medicine assessed didn’t present efficacy in the R. (B.) microplus control, and didn’t interfere in the reproductive parameters of engorged females. Finally, in the study "Alternative methods for egg hatch evaluation of Rhipicephalus (Boophilus) microplus" in which two techniques of egg hatching estimation were compared, engorged females collected from cattle were subject to the AIT with plant extracts and kept in an incubator to perform oviposition. Eggs were transferred to syringes and incubated for 15 days. Egg hatching was evaluated in 210 syringes by visual estimation (%) and also counted until 100 in three repetitions. Significant differences were found between the two tests. In the visual estimation (56.8%) the hatching percentage average was higher than in the quantification by sampling (48.0%). In quantification by sampling, no statistical differences were observed in the pairwise counts between the three samples (48.1, 47.8 and 48.1%) and, the correlation of repetitions was 0.96, suggesting that the count of one sample is sufficient and the result should not differ much, regardless of the evaluator. The present study contributed with unreleased information about the acaricide and repellent effect of O. elegans. It was discussed that despite the homeopathic medicine had not effect, such conclusion cannot be extended to other homeopathic formulations, process of application and management conditions adverse to the present study. Finally, the results of the comparative study contribute for the improvement of the AIT and may encourage researchers to choose more reliable techniques in the assessment of the egg hatching.
The parasitism by Rhipicephalus (Boophilus) microplus causes large economic loss in cattle herds and its control through chemical acaricides faces problems of resistance and residues in food and in the environment. Aiming to contribute with relevant information for the control of this parasite, the present study had three objectives: 1) evaluate the effect in vitro of Ocotea elegans essential oil on larvae and engorged females of R. (B.) microplus, 2) evaluate homeopathic medicine to control R. (B.) microplus natural infestations, and 3) compare visual estimation and quantification by sampling techniques of larvae hatching in the engorged females immersion test, due to the importance of this technique in the screening of substances with antiparasitic action. In the first experiment, "In vitro acaricidal and repellent effect of Ocotea elegans essential oil on R. (B.) microplus", were adopted the tests: larval packet test (LPT), the larval repellency test (RT) and the adult immersion test (AIT). In order to verify efficacy, O. elegans was evaluated at concentrations of 0.78 mg/mL to 100 mg/mL. In the AIT, from the concentration of 25 mg/ml, the efficacies were higher than 90%. LPT (48h) at 100 mg/mL resulted in mortality rates higher than 70%. The RT obtained repellency higher than 80% sice the lowest concentration evaluated. In relation to the lethal concentrations, the lowest LC50 obtained in the LPT was 25.59 mg/mL, 48 hours post treatment. The LC50 and LC90 in the AIT were 4.96 and 17.37 mg/mL and in TR were 0.04 and 1.24 mg/mL, respectively. It was possible to conclude that O. elegans had significant effect in engorged females and larvae repellency and may be in the future an adjuvant for tick control, prioritizing in vivo tests. In the second experiment, “Study of homeopathy in the control of natural infestation of R. (B.) microplus in dairy cattle”, 24 females of the Dutch and Jersey x Dutch breed were divided in the control group (placebo) and treated (biotherapic 30 CH + Sulphur 30 CH) (n=12), administered in the concentrate at 2 kg/animal/day for 12 months. It was collected in each group engorged females to compare the reproductive parameters, and semi-engorged females for the ovaries histologic evaluation. The live weight (LW), packed cell volume (PCV) and counts of engorged females in the animals’ body were held. The average results of LW, PCV and ticks were not statistically different in the control and homeopathic groups: 616.5 kg and 618.6 kg, 27.9% and 27.3%, 12.19 and 13.58 ticks, respectively. In the in vitro analyzes, the average weight of females (0.18 and 0.17 g), egg weight (0.07 and 0.06 g), larvae hatching % (70.1 and 76.6%) and reproductive efficiency index (54.3 and 60.6%), to control and homeopatic groups, respectively, had no statistical difference as well. In addition, no changes in the ovaries were observed in microscopy. Therefore, the homeopathic medicine assessed didn’t present efficacy in the R. (B.) microplus control, and didn’t interfere in the reproductive parameters of engorged females. Finally, in the study "Alternative methods for egg hatch evaluation of Rhipicephalus (Boophilus) microplus" in which two techniques of egg hatching estimation were compared, engorged females collected from cattle were subject to the AIT with plant extracts and kept in an incubator to perform oviposition. Eggs were transferred to syringes and incubated for 15 days. Egg hatching was evaluated in 210 syringes by visual estimation (%) and also counted until 100 in three repetitions. Significant differences were found between the two tests. In the visual estimation (56.8%) the hatching percentage average was higher than in the quantification by sampling (48.0%). In quantification by sampling, no statistical differences were observed in the pairwise counts between the three samples (48.1, 47.8 and 48.1%) and, the correlation of repetitions was 0.96, suggesting that the count of one sample is sufficient and the result should not differ much, regardless of the evaluator. The present study contributed with unreleased information about the acaricide and repellent effect of O. elegans. It was discussed that despite the homeopathic medicine had not effect, such conclusion cannot be extended to other homeopathic formulations, process of application and management conditions adverse to the present study. Finally, the results of the comparative study contribute for the improvement of the AIT and may encourage researchers to choose more reliable techniques in the assessment of the egg hatching.
Descrição
Palavras-chave
Carrapato, Fitoterapia, Homeopatia, Resíduos, Resistência, Contagem de larvas, Tick, Herbal medicine, Homeopathy, Residues, Resistance, Counting of larvae