11 |
Role of P-glycoprotein in Haemonchus contortus anthelmintic resistance.Garretson, Pamela Donn 15 May 2009 (has links)
The gastrointestinal parasite, Haemonchus contortus, is of major concern in the
sheep and goat industry as well as in zoological settings. Over the years this parasite has
developed resistance to the three classes of anthelmintics, benzimidazoles,
imidazothiazoles and macrocyclic lactones, that are currently used for treatment. One of
the mechanisms proposed to be involved in this resistance is the efflux transporter
P-glycoprotein (Pgp). In this study, the resistance status of several strains of
H. contortus was evaluated using the larval development assay DrenchRite®. After
documenting the resistance status of these strains, transcription of Pgp in L3 larvae after
exposure to anthelmintics was quantitated using polymerase chain reaction (PCR). Of
the strains analyzed, only one was determined to be susceptible to all of the
anthelmintics tested, while the others showed variable levels of resistance to one or
more. A Haemonchus strain acquired from a giraffe at a zoo in Florida was the most
resistant, showing extremely high levels of resistance to benzimidazoles and levamisole.
Molecular characterization of the 18S rRNA gene and the internal transcriber spacer
region (ITS) were performed on the giraffe strain to identify the species. Although there
were variations in the isolate sequences, the most likely species for the giraffe strain was
H. contortus. No transcription of Pgp was identified in H. contortus L3 larvae under the conditions of this study. Thus, increased Pgp does not appear to be a primary
mechanism of drug resistance in this stage of the worm.
|
12 |
Molecular Weight of Condensed Tannins from Warm-season Perennial Legumes and Its Effect on Condensed Tannin Biological ActivityNaumann, Harley Dean 16 December 2013 (has links)
Condensed tannins (CT) are polyphenolic compounds that have demonstrated biological activities in ruminants including suppression of enteric methane (CH4) production, protein binding and suppression of gastrointestinal nematode (GIN) infections. Some forage CT have been reported to be biologically active, whereas others have demonstrated no biological activity at all. While the chemical structure of CT has been postulated to be a key contributing factor affecting biological activity, the specific factors that determine whether or not CT from a specific forage have bioactive properties remain unknown. Results from previous studies have shown that as molecular weight of CT increases, CT biological activity also increases. Others have reported no effect of CT molecular weight on biological activity. The relationship between molecular weight of CT and CT biological activity remains inconclusive. The effect of molecular weight of CT from a variety of warm-season perennial legumes commonly consumed by ruminants on biological activity has not been adequately explored. The objectives of this study were to determine if molecular weight of CT from warm-season perennial legumes could predict the biological activity of CT relative to suppression of enteric CH4 production, protein-binding ability (PB) and anthelmintic activity, and to compare the biological activity of CT from native warm-season perennial legumes to that of the introduced species Lespedeza cuneata, a plant that has gained attention in recent years due its anthelmintic properties.
All or a combination of the following warm-season perennial legume species were evaluated for in vitro gas production, protein-precipitable phenolics (PPP) and PB, and percent larval migration inhibition (LMI). Eight North American native warm-season perennial legumes: Leucaena retusa Benth. (littleleaf leadtree), Desmanthus illinoensis (Michx.) MacMill. Ex B.L. Rob. & Fernald (Illinois bundleflower), Lespedeza stuevei Nutt. (tall lespedeza), Mimosa strigillosa Torr. & A. Gray (powderpuff), Neptunia lutea (Leavenworth) Benth. (yellow puff), two ecotypes of Acacia angustissima var. hirta (Nutt.) B.L. Rob (prairie acacia), Desmodium paniculatum (L.) DC. var. paniculatum (panicledleaf ticktrefoil), and two introduced legumes: Arachis glabrata Benth. (rhizoma peanut) and Lespedeza cuneata (Dum. Cours.) G. Don (sericea lespedeza) were included.
In vitro CH4 production regressed on CT MW resulted in a R2 of 0.0009 (P = 0.80). There was no correlation between PPP or PB and MW of CT (R^2 0.11; P = 0.17 and R^2 0.02; P = 0.54, respectively). There was a weak correlation between CT MW and percent LMI (R^2 0.34; P = 0.05). The results of our study strongly suggested that CT MW does not explain the biological activities of enteric methane suppression or protein-binding ability. Condensed tannin MW may be involved in anthelmintic activity of CT from the forage legumes surveyed. North American native legumes containing biologically active CT, as compared to introduced species, were identified as having promise for use in ruminant diets.
|
13 |
Investigations into the use of continuous low-level medication for the control of helminths in the ruminantDobbins, Sally Elizabeth January 1984 (has links)
The work presented in this thesis is concerned with the chemotherapy of parasite infestations in the ruminant with the anthelmintic thiophanate [diethyl 4,4'-o-phenylene bis (3-thioallophanate)]. A new concept of administration was investigated, namely continuous low-level anthelmintic medication. Two aspects were studied which divide conveniently into two sections. In Section 1, following preliminary trials undertaken to assess the low-level anthelmintic activity of thiophanate, the effects are assessed when this drug is administered continually directly into the rumen of parasitised sheep. Thiophanate was infused at dosages between 3.0 and 5.0 mg per kg bodyweight over various periods of medication against various developmental stages of gastro-intestinal parasites. The daily drug release rate. required to inhibit egg hatch and eliminate the worm burden is established. A minimum daily release rate of 3.0 mg per kg bodyweight was shown to be required to completely inhibit egg hatch and 4.5 mg per kg for effective vermicidal activity. In similar experiments, the anthelmintic activities of levamisole (s-(-)-2,3,5,6-tetrahydro-6-phenylimidazo (2,1-b) thiazole), febantel (N-(2-(2,3-bis-(methoxycarbonyl)-guanidino)-5-(phenyl-thio)-phenyl)-2-methoxy-acetamide) and briefly oxfendazole (5-(phenylsulfinyl)-IH-benzimidazol-2yl) carbamate) were also examined. In Section 2, the development of an intra-ruminal bolus incorporating thiophanate and designed to release drug at a predetermined rate over an extended period of time is described. Experiments were carried out in sheep to assess the bolus density required for retention within the reticulo-rumen (monitored by direct bolus recovery), to compare various density factors (iron powder, iron bar core, iron shot and sand) and to assess the average drug release rate from different matrix formulations (based on fatty acids, palmitic acid and paraffin wax) when the boluses were dosed singly or in pairs. The development of a stable "carrier" on which to load a suitable matrix is also described, the majority of the experiments undertaken utilising this "carrier". The effect on the drug release rate of incorporating various "leaching aids" (digestible materials, wetting and soluble agents) into the matrix is examined and preliminary anthelmintic trials undertaken in experimentally infected lambs. The required drug release is achieved when the boluses are administered in pairs. The anthelmintic activity is confirmed. Possible matrices suitable for use as a single bolus administration were produced. The advantages of this form of anthelmintic medication over the single therapeutic dose are discussed along with some indications for further studies that emerged.
|
14 |
Ectopic Expression in Remodeled C. elegans: A Platform for Target Identification, Anthelmintic Screening and Receptor DeorphanizationLaw, Wen Jing January 2015 (has links)
No description available.
|
15 |
Interactions of Teladorsagia circumcincta with the ovine immune system : mimicry and vaccine developmentEllis, Samantha Emma Elizabeth January 2014 (has links)
Teladorsagia circumcincta, an economically-important abomasal nematode of small ruminants in temperate regions worldwide, is currently controlled with a combination of anthelmintics and pasture management. Anthelmintic resistance has emerged and vaccination is a potential alternative control strategy, as protective immunity in sheep can be acquired after repeated exposure to the parasite. Abomasal mucosal IgA responses in immune sheep have been correlated with delayed worm development and reduced faecal egg counts. However, recombinant vaccine development against parasitic nematodes has had limited success, and one of the reasons may be unsuitable expression systems for antigen production leading to incomplete or inadequate post-translational modifications such as glycosylation and tertiary protein folding, resulting in incorrect epitope structures for antibody binding. In this thesis, to address this issue, “native” infective larval (L3) antigen targets of protective immune responses and synthetic peptide sequences which mimic structural epitopes on these antigens were identified. Abomasal mucosal IgA was used as a probe to identify native immunogenic antigens from T. circumcincta L3. IgA was purified from abomasal mucus of animals rendered immune by repeated experimental infection and a custom antibody-affinity column was created and used to purify antigens from an L3 somatic PBS-soluble extract. Affinity purified L3-antigen-specific IgA levels in sheep with varying levels of immunity to T. circumcincta were positively correlated (rs = 0.853, P < 0.001) with both the total IgA concentration in efferent gastric lymph after parasite challenge, and with the percentage of inhibited fourth-stage (L4) larvae present in the gastric glands of the immune hosts (rs = 0.534, P = 0.007). In contrast, a negative correlation between the levels of affinity-purified L3 antigen-specific IgA and total T. circumcincta burden was observed (rs = -0.565, P = 0.004). Proteomic analysis of the IgA-affinity purified L3 extract identified a number of proteins which represent potential vaccine candidate molecules in other helminth species, including paramyosin, superoxide dismutase, galectin, activation-associated secreted proteins and fatty-acid retinol-binding proteins. As a first step towards the development of a novel vaccine based on IgA-binding peptide mimics of native structural epitopes, phage display libraries were used to screen antibodies, from sheep rendered immune to T. circumcincta by experimental infection. These antibodies were affinity-purified before use and specifically bound T. circumcincta L3 glycans or, alternatively, surface antigens on exsheathed T. circumcincta L3. Five peptide sequences which mimic L3 antigenic epitopes were identified and positive correlations existed between peptide-specific IgA levels and both the total IgA concentration in efferent gastric lymph after parasite challenge and the percentage of inhibited L4 present (rs > 0.621, P < 0.001 to P < 0.05). In contrast, negative correlations between the levels of peptide-specific IgA and the total nematode burden were observed (rs > -0.528, P < 0.01 to P < 0.05). In conclusion, the selected phage clones may therefore represent vaccine candidates if they could be presented to the ovine immune system in an appropriate fashion.
|
16 |
Inhibition of infective larvae exsheathment and egg hatching of the nematode Haemonchus contortus with extracts of tannin-rich plants / Inibições do desembainhamento de larvas infectantes e da eclodibilidade do nematoide Haemonchus contortus com extratos de plantas taniníferasGomes, Edgard Franco 23 September 2013 (has links)
The aim of this work was to assess the bioactivity of extracts of the tannin-rich plants Acacia mearnsii, Myracrodruon urundeuva, Caesalpinea bracteosa and Leucaena leucocephala against egg and infective larvae stages of Haemonchus contortus. Two in vitro assays were held: an Egg Hatch Assay (EHA) and a Larval Exsheathment Inhibition Assay (LEIA). The EHA consists of the incubation of previously recovered eggs from infected animal\'s faeces in a solution of plant extract for 24 hours and later differentiation between larvae and nonhatched eggs. The concentrations used were 50.00, 25.00, 12.50, 6.25, 3.12, 1.56, 0.78 and 0.39 mg/mL for A. mearnsii; 1.56, 0.78, 0.39, 0.19, 0.09 and 0.04 mg/mL for M. urundeuva; 6.25, 3.12, 1.56, 0.78, 0.39 and 019 mg/mL for C. bracteosa; and 6.25, 3.12 and 1.56 mg/mL for L. leucocephala. The LEIA consists in the artificial exsheathment of infective larvae, obtained by previous coproculture, after a three hour incubation period with plant extract solution in the concentrations 1,200, 600, 300 and 150 \'mü\'g/mL. The 50 and 99 lethal doses (LD) were calculated for both tests. A dose-dependent effect was found in the two tests, except for L. leucocephala in EHA, where it was not possible to calculate DL50 and DL99 with the chosen doses. The DL50 results for EHA were 0.18, 0.32, and 7.20 mg/mL and for DL99 were 4.31, 5.41, and 187.26 mg/mL, respectively for M. urundeuva, C. bracteosa, and A. mearnsii. For LEIA, the DL50 were 0.40, 0.52, 1.24, and 2.24 mg/mL and for DL99 these were 2.37, 2.28, 19.99 and 2.53 x 103 mg/mL respectively for M. urundeuva, A. mearnsii, L. leucocephala and C. bracteosa. The two highest concentrations of A. mearnsii and the three highest for C. bracteosa were effective (more than 90% of bioactivity); the three highest concentrations of M. urundeuva and the 0.78 mg/mL level of C. bracteosa were moderately effective (between 80 and 90% of bioactivity); the concentrations with low effectiveness (between 60 and 80% of bioactivity) were the 12.50 mg/mL (A. mearnsii), 0.19 mg/mL (M. urundeuva), and 0.39 mg/mL (C. bracteosa); all other concentrations were ineffective (less than 60% of bioactivity). For the LEIA, only the highest dose from A. mearnsii and M. urundeuva were effective; the 600 \'mü\'g/mL were moderately effective and all other doses were ineffective. It should be observed that even if the dose is ineffective against exsheathment, some concentrations were able to significantly delay the process. It was observed that the extracts had bioactivity in vitro within the chosen doses against the hatchability of eggs and exsheathment of larvae of H. contortus, except for L. leucocephala, which was not able to block the hatching of eggs / Objetivou-se com o presente trabalho verificar a bioatividade dos extratos das plantas taniníferas Acacia mearnsii, Myracrodruon urundeuva, Caesalpinea bracteosa e Leucaena leucocephala contra os estágios de ovo e de larva L3 infectante de Haemonchus contortus. Para isso, dois ensaios in vitro foram realizados: o Teste da inibição da eclodibilidade dos ovos (TIEO) e o teste da Inibição do desembainhamento larvar (TIDL). O TIEO consiste na incubação de ovos recém recuperados das fezes de animais infectados em solução liquida de extrato de planta por 24 horas e posterior diferenciação entre larvas e ovos não eclodidos. As concentrações utilizadas para A. mearnsii foram de 50,00, 25,00, 12,50, 6,25, 3,12, 1,56, 0,78 e 0,39 mg/mL; 1,56, 0,78, 0,39, 0,19, 0,09 e 0,04 mg/mL para M. urundeuva; 6,25, 3,12, 1,56, 0,78, 0,39 e 0,19 mg/mL para C. bracteosa; e 6,25, 3,12 e 1,56 mg/mL para L. leucocephala. O TIDL consiste no desembainhamento artificial de larvas infectantes, obtidas através de coprocultura, que passaram por período de incubação de três horas em solução liquida de extratos de plantas nas concentrações 1.200, 600, 300 e 150 \'mü\'g/mL. As doses letais (DL) 50 e 99 foram calculadas para ambos testes. Um efeito dose-dependente foi encontrado para os dois testes, exceto para a L. leucocephala no TIEO, onde não foi possível calcular o valor da DL50 e DL99 para o respectivo teste nas doses escolhidas. Os resultados da DL50 para TIEO foram de 0,18, 0,32 e 7,20 mg/mL e da DL99 foram de 4,31, 5,41 e 187,26 mg/mL respectivamente para M. urundeuva, C. bracteosa e A. mearnsii. Para o TIDL, a DL50 foi de 0,40, 0,52, 1,24 e 2,24 mg/mL e da DL99 foi de 2,37, 2,28, 19,99 e 2,53 x 103 mg/mL respectivamente para M. urundeuva, A. mearnsii, L. leucocephala e C. bracteosa. Para o TIEO, as duas maiores concentrações de A. mearnsii e as três maiores de C. bracteosa foram efetivas (mais de 90% de bioatividade); as três maiores concentrações de M. urundeuva e a 0,78 mg/mL de C. bracteosa foram moderadamente efetivas (entre 80 e 90% de bioatividade); as concentrações de pouca efetividade (entre 60 e 80% de bioatividade) foram a 12,50 mg/mL (A. mearnsii), 0,19 mg/mL (M. urundeuva), e 0,39 mg/mL (C. bracteosa); as demais concentrações foram consideradas ineficientes (menos de 60% de bioatividade). Para o TIDL, apenas a maior concentração de A. mearnsii e M. urundeuva foram efetivas; a concentração de 600 \'mü\'g/mL de M. urundeuva foi moderadamente efetiva; todas as outras concentrações foram ineficientes. Entretanto, deve-se observar que apesar de ineficientes em bloquear o desembainhamento, algumas concentrações atrasaram significativamente o desembainhamento das larvas, sendo esse um resultado de interesse. Assim, foi observado que os extratos, excetuando o extrato de L. leucocephala quanto a eclodibilidade, possuem bioatividade in vitro nas doses utilizadas contra a eclosão dos ovos e contra o desembainhamento das larvas de H. contortus
|
17 |
Uso de resíduos da cultura da bananeira (Musa spp.) para alimentação e controle de endoparasitas de ruminantes / Banana (Musa spp.) plantation residues to feed and control endoparasites of ruminantsSampaio, Paulo Henrique Selbmann 30 August 2016 (has links)
A bananeira é cultivada pelo homem há pelo menos 6.500 anos. O início desse processo foi marcado pela manifestação espontânea dos fenômenos de partenocarpia, hibridização, poliploidia e pela sua combinação, gerando diferentes cultivares, cujos clones foram selecionados por agricultores primitivos e se disseminaram pelos trópicos, exclusivamente pela ação humana. A banana é hoje a principal fruta cultivada no mundo, existindo farta documentação sobre a utilização dos resíduos da cultura para alimentação de animais e sobre o uso medicamentoso de diferentes partes da planta. No âmbito da Medicina Veterinária, folhas, inflorescências masculinas, pseudocaules e rizomas já foram testados in vitro e in vivo para avaliação de seu efeito anti-helmíntico. Entretanto, em escala comercial, toda essa biomassa deve permanecer no bananal, para cobertura e fertilização do solo, inviabilizando seu aproveitamento como forragem. Por outro lado, no momento da colheita, os cachos de bananas são levados para unidades de triagem denominadas “packing-houses”, onde as frutas são selecionadas e acondicionadas para expedição, restando os engaços ou pedúnculos dos cachos de bananas disponíveis para o aproveitamento na alimentação animal, com o benefício adicional potencial de controlar infecções verminóticas. O presente trabalho demonstrou que o extrato dos engaços do cultivar “Nanica”, Subgrupo Cavendish AAA, inibiu significativamente a eclosão in vitro de ovos de Haemonchus contortus, da mesma forma que extratos de folhas e pseudocaules. Transpondo esse achado para um modelo in vivo, 24 cordeiros inteiros, ⅞ Dorper, foram experimentalmente infectados com larvas de Haemonchus contortus e alocados em blocos a cada um de quatro tratamentos, de acordo com as contagens de ovos nas fezes. Os ovinos receberam, conforme o grupo, 0% (controle), 10%, 20% ou 30% de engaços frescos de bananeira picados, calculados em matéria seca, sendo a dieta complementada com feno de braquiária ad libitum e sal mineral. Os animais foram tratados durante 14 dias consecutivos. Glucose de milho e melaço de cana de açúcar foram utilizados para melhorar a aceitação dos engaços pelos animais. Verificou-se um aumento significativo da oviposição em todos os grupos tratados na primeira semana de tratamento, fato possivelmente relacionado com um dos efeitos farmacológicos da bananeira, que promove elevação da serotonina e, por consequência, aumenta a taxa de reprodução dos nematódeos. Na segunda semana obteve-se redução significativa das contagens de ovos nas fezes, sem diferença estatística entre os grupos tratados, sugerindo que o uso continuado dos engaços de bananeira na alimentação pode promover um controle das infecções helmínticas em ruminantes. Demonstrou-se ainda que os taninos condensados exercem papel marginal quando a bananeira é testada in vitro, pois, nesse caso, a adição de polivinilpolipirrolidona, substância capaz de precipitar e suprimir a atividade desses taninos, proporcionou o mesmo grau de inibição da eclosão de ovos de Haemonchus contortus que os extratos puros. Embora relatos recentes tenham sugerido a presença de alcalóides e saponinas na bananeira, tais compostos não foram identificados nas amostras estudadas. Observou-se, todavia, a presença de siringina, um fenilpropanóide, cuja via metabólica engloba as defesas bioquímicas dos cultivares de bananas contra infecções por nematódeos parasitos de plantas. Não obstante, a presença de catecolaminas e ação antiparasitária de esteróis e triterpenos sugerem fortemente que a bananeira atua como um fitocomplexo quando fornecida aos ruminantes como alimento e tratamento contra endoparasitos. / The banana plant has been cultivated by men for at least 6,500 years. The beginning of this process was marked by the spontaneous occurrence of the phenomena of partenocarpy, hybridization, polyploidy and their combination, generating different cultivars, which clones were selected by primitive farmers and were disseminated throughout the tropics, by exclusive human action. Nowadays bananas are the main fruit crop cultivated in the world, and there is plenty documentation regarding the use of crop residues to feed animals and concerning the medicinal use of different parts of the plant. In the field of Veterinary Medicine, leaves, masculine inflorescences, pseudostems and rhizomes have been tested both in vitro and in vivo for the evaluation of their anthelminthic effect. However, in commercial scale, all this biomass has to be kept in the plantation, to cover and fertilize the soil, frustrating its use as forage. On the other hand, at the moment of harvesting, banana bunches are carried to screening facilities called “packing-houses”, where the fruits are selected and boxed for shipment, leaving the stalks or peduncles of the bunches available to be used as animal fodder, with the potential additional benefit of controlling worm infections. The current work has shown that the extract of the cultivar “Nanica”, Subgroup Cavendish AAA, has significantly inhibited the in vitro eclosion of Haemonchus contortus eggs, in the same manner as extracts of leaves and pseudostems. Transposing this finding to an in vivo model, 24 non-castrated ⅞ Dorper lambs were experimentally infected with Haemonchus contortus larvae and allocated in blocks to each of four treatments, according to their faecal egg counts. The sheep were fed, according to the group, 0% (control), 10%, 20% or 30% fresh chopped banana plant stalks, calculated as dry matter, while the diet was complemented with Brachiaria hay ad libitum and mineral salt. The animals were treated during 14 consecutive days. Maize glucose and sugar cane molasses were used to improve the acceptance of the stalks by the lambs. There was a significant increase of the oviposition in all treated groups during the first week of treatment, fact possibly related to one of the pharmacological effects of the banana, which promotes an increase of serotonin levels, consequently enhancing the reproductive tax of the nematodes. On the second week a significant reduction of the faecal egg counts was noted, without statistical difference between the treated groups, suggesting the continuous use of the banana plant stalks as feed may promote a control of helminthic infections in ruminants. It was further shown that condensed tannins play a marginal role when the banana plant is tested in vitro, because the addition of polyvinylpolypyrrolidone, a substance capable of precipitating and supressing the activity of these tannins, resulted in the same level of Haemonchus contortus egg hatch inhibition obtained with the pure extracts. In spite of recent reports suggesting the presence of alkaloids and saponins in the banana plant, these compounds were not detected in any of the samples tested. Otherwise, screening identified syringing, a phenylpropanoid, which metabolic pathway comprises the biochemical defences of the banana cultivars against infections by nematode plant parasites. The presence of catecholamines and the anti-parasitic action of sterols and triterpenes strongly suggest the banana plant acts as a phytocomplex when administered to ruminants as feed and treatment against endoparasites.
|
18 |
Nicotinic acetylcholine receptors from the parasitic nematode Ascaris suumWilliamson, Sally January 2008 (has links)
Nematodes of the genus Ascaris are large gastrointestinal parasites. Ascaris lumbricoides infects ~1 billion people globally; causing malnutrition and general morbidity, and can block the gut or bile duct causing fatal complications. Ascaris suum is a parasite of pigs; in addition to its veterinary significance, it can occasionally be zoonotic, and is a good model of the human parasite. One of the main classes of drugs used to treat parasitic nematode infections are the cholinergic anthelmintics, such as levamisole and pyrantel, which act as agonists of nicotinic acetylcholine receptors at the nematode neuromuscular junction.
|
19 |
Estudo da resistência anti-helmíntica de bovinos aos nematódeos gastrintestinais: uma meta-anàliseBaiak, Barbara Haline Buss 29 August 2017 (has links)
Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2017-10-25T16:15:30Z
No. of bitstreams: 2
license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5)
BARBARA BAIAK.pdf: 851854 bytes, checksum: ec3cb108a9139e9eea278fc05bef5f2e (MD5) / Made available in DSpace on 2017-10-25T16:15:30Z (GMT). No. of bitstreams: 2
license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5)
BARBARA BAIAK.pdf: 851854 bytes, checksum: ec3cb108a9139e9eea278fc05bef5f2e (MD5)
Previous issue date: 2017-08-29 / As infecções causadas por nematódeos gastrintestinais em bovinos são comuns, sua
patologia prejudica a saúde e bem estar dos animais, resultando em perdas na produção de
leite e carne. Como a transmissão destes parasitas se dá no pasto, geralmente o que se
encontra são infecções mistas, ou seja, mais de um gênero ou espécie parasitando o mesmo
animal. Os anti-helmínticos são utilizados para o controle destes parasitas há anos. O uso
indiscriminado, a utilização do mesmo composto químico sem alternância, as subdosagens,
são fatores que podem causar a resistência anti-helmíntica. Devido ao aumento nos relatos de
resistência à estes compostos em bovinos, o objetivo do trabalho foi estimar através da metaanálise
a resistência anti-helmíntica de bovinos aos nematódeos gastrintestinais. Os dados
para composição da base foram obtidos a partir de artigos e resumos publicados em bases
indexadoras. Os mesmos foram avaliados criteriosamente conforme sua qualidade e
importância segundo os objetivos da meta-análise. Foram tabulados informações referentes
aos aspectos bibliográficos, anti-helmínticos, animais, métodos de redução, dias após
aplicação, tipo de infecção, gêneros dos parasitas, tipo de aplicação e dosagem do antihelmíntico.
A base final dos dados foi composta por 80 artigos publicados entre 1986 e 2016,
perfazendo um total de 9516 bovinos. A análise gráfica foi utilizada como primeiro passo para
observar a distribuição dos dados, seguidas de análise de variância e comparações pelo teste
Tukey. Equações de predição foram realizadas a partir dos coeficientes obtidos nas análises de
variância-covariância. Para demonstrar o valor sumarizado da meta-análise foi realizado o
forest plot. O tipo de aplicação interferiu na eficácia dos anti-helmínticos em bovinos
(P<0,05); aplicação oral foi superior a injetável e a pour on. Nos grupos químicos e princípios
ativos, o grupo “associados” apresentou média de eficácia superior as lactonas macrocíclicas e
ivermectina com as menores médias (P<0,05).O uso composto demonstrou superioridade em
relação ao uso único (P<0,05). O tipo de infecção, método de redução, idade e grupo racial
não apresentaram interferência (P>0,05) na eficácia dos anti-helmínticos. Em relação aos
gêneros de nematódeos gastrintestinais, o princípio ativo levamisol apresentou a maior média
de eficácia para os gêneros Cooperia spp. e Trichostrongylus spp. Estes diferiram de
Ostertagia spp. (P<0,05). Para os gêneros Ostertagia spp. e Trichostrongylus spp. a eficácia
da ivermectina foi de 100%, estes diferiram de Cooperia spp. e infecções mistas (P<0,05). A
porcentagem média de eficácia para doramectina foi maior para Ostertagia spp. diferindo de
Cooperia spp. (P<0,05). Nos princípios ativos listados na categoria “outros” a maior média
foi registrada no gênero Ostertagia spp. diferindo de Haemonchus spp. (P<0,05). Na
utilização de princípios ativos associados e moxidectina, não houve diferença (P>0,05) entre
os gêneros. Equações de predição demonstraram que para o princípio ativo levamisol a
eficácia do anti-helmíntico aumenta proporcionalmente conforme a dose, e que a eficácia
diminui conforme o passar dos dias após a aplicação. O forest plot com I²=94% demonstrou
alta heterogeneidade entre os dados, sendo o valor sumarizado classificado como resistente
(P>0,05). Este estudo evidencia a resistência anti-helmíntica em bovinos em vários
continentes, onde apenas o uso associado mostrou eficácia. Portanto, é necessário substituir os
esquemas com base no uso exclusivo de compostos químicos para diminuir a pressão de
seleção. / Infections caused by gastrointestinal nematodes in cattle are common; they can prejudice the
health and welfare of animals, resulting in losses in milk and meat production. As the
transmission of these parasites occurs in the pasture, what is usually found are mixed
infections, that is, more than one nematode genera parasitizing the same animal. The
anthelmintics have been used to control these parasites for years. The indiscriminate use, the
utilization of the same chemical compound without alternation, the underdosage, are factors
that can cause the anthelmintic resistance. Due to the increase in the reports of resistance to
these compounds in cattle, the objective of the study was to estimate through the metaanalysis
the anthelmintic resistance in cattle by gastrointestinal nematodes. Data for the
composition of the database were obtained from articles and short communications published
in index databases. They were carefully evaluated according to their quality and importance
according to the meta-analysis objectives. It were tabulated information about the
bibliographic, anthelmintic, animal, reduction method, days after application, type of
infection, parasite genera, type of application and dosage. The final data base was composed
of 80 articles between 1986 and 2016, making a total of 9516 animals. The graphical analysis
was used as a first step to observe the data distribution, followed by analysis of variance and
comparisons by the Tukey test. Prediction equations were performed from the coefficients
obtained in the variance-covariance analyzes. In order to demonstrate the summary value of
the meta-analysis, the "forest plot" was performed. The type of application interfered in the
efficacy of anthelmintics in cattle (P<0.05), oral application was superior to injectable and
pour on. In the chemical groups and active principles, the associated group presented better
mean of efficacy (>95%), macrocyclic lactones and ivermectin showed the worse means
(P<0.05). The associated use showed superiority in relation to unique use (P<0.05). The type
of infection, reduction method, age and racial group did not show interference (P>0.05) in the
efficacy of anthelmintics. In relation to nematode genera, levamisole presented the highest
average of efficacy for the genera Cooperia spp. and Trichostrongylus spp. differed from
Ostertagia spp. with the worse average (P<0.05), ivermectin showed the highest average for
Ostertagia spp. and Trichostrongylus spp., Cooperia spp. and mixed infection presented
worse average (P<0.05), doramectin presented the highest average for Ostertagia spp., and
the worse for Cooperia spp. (P<0.05). In the active principles listed in the category "others"
the highest average was recorded in the genera Ostertagia spp. differing from Haemonchus
spp. with the worse average (P <0.05). Associated active principles and moxidectin, did not
show significance between the nematode genera (P>0.05). Prediction equations showed that
for the levamisole the efficacy of the drug increases proportionally according to the dose, and
that the efficacy decreases as the days pass after the application. The forest plot showed high
heterogeneity among the data, being the summarized value classified as resistant (P>0.05).
This study evidences the anthelmintic resistance in cattle on several continents, where only
the associated use showed efficacy. Therefore, there is a need to replace the schemes based on
the exclusive use of chemical compounds in order to decrease the selection pressure.
|
20 |
Taninos condensados de fabaceas nativas da caatinga e seu potencial na atividade anti-helmíntica em caprinos / Native fabaceae of condensed tannins of the caatinga and its potential for anthelmintic activity in goatsCOSTA FILHO, Marco Hamilton Barros da 29 July 2016 (has links)
Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-02-13T15:14:35Z
No. of bitstreams: 1
Marco Hamilton Barros da Costa Filho.pdf: 2573105 bytes, checksum: f63c114b9f31e4964f056d2413f14839 (MD5) / Made available in DSpace on 2017-02-13T15:14:35Z (GMT). No. of bitstreams: 1
Marco Hamilton Barros da Costa Filho.pdf: 2573105 bytes, checksum: f63c114b9f31e4964f056d2413f14839 (MD5)
Previous issue date: 2016-07-29 / The gastrointestinal helminth infections represent one of the main causes in limiting the production of small ruminants around the world. In the search for new alternatives for effective control of these gastrointestinal nematodes, phytotherapy is presented as a promising sector in an attempt to reduce the use of chemical treatments. Making the study of plants with the potential taninífero an alternative anthelmintic control. Once these tannins identified and isolated, it becomes increasingly more practical in its real potential anthelmintic activity. In this sense, we chose species Black Jurema (Mimosa tenuiflora (Willd) Poiret), red angico (Anadenanthera macrocarpa (Benth.) Brenan) and catingueira (Poincianella pyramidalis Tul.) For chemical-bromatological characterization and quantification of the condensed tannin levels in the different fractions of the plant. These Fabaceae were collected in Caatinga area preserved the Sertânia municipality in semiarid region of Pernambuco. Leaf samples were collected with stem and bark of each species and quantification of condensed tannins in the Fabaceae study used the butanol-HCl method. Data were analyzed using descriptive statistics. In this sense, combining obtaining the purified extract of condensed tannin, held anthelmintics trials through larval development tests (TDL) in vitro fecal material collected from Saanen goats naturally infected under management of concentrations in treatments (37.5, 75, 150, 300 and 350 mg/ml) in four replicates each of purified extract of tannins, together with control treatment, positive and negative, with levamisole hydrochloride at a concentration of 7.5 mg / ml and distilled water, respectively. Mimosa tenuiflora (Willd) Poiret. He stood between native Fabaceae with the highest total concentration of tannin, in all fractions of the plant. In anthelmintic activity, significant effect, making it an excellent alternative for controlling gastrointestinal nematodes in small ruminants. / As infecções por nematódeos gastrintestinais correspondem a uma das principais causas limitantes na produção de pequenos ruminantes em todo o mundo. Na busca por novas alternativas de controle efetivo desses parasitos, a fitoterapia se apresenta como um setor promissor na tentativa de reduzir a utilização de tratamentos químicos. Tornando o estudo de plantas com potencial taninífero uma alternativa ao controle anti-helmíntico. Uma vez esses taninos identificados e isolados, torna-se cada vez mais concreto seu real potencial na atividade anti-helmíntica. Neste sentido, escolheu-se as espécies jurema preta (Mimosa tenuiflora (Willd) Poiret), angico vermelho (Anadenanthera macrocarpa (Benth.) Brenan) e catingueira (Poincianella pyramidalis Tul.) para caracterização químico-bromatológica e quantificação dos teores de taninos condensados nas diferentes frações da planta. Estas fabaceas foram coletadas em área de Caatinga preservada do município de Sertânia na região Semiárida de Pernambuco. Foram coletadas amostras de folhas com haste e casca de cada espécie, e para quantificação dos taninos condensados das fabaceas em estudo foi utilizado o método do butanol-HCl. Os valores obtidos foram analisados através de estatística descritiva. Nesse sentido, aliando a obtenção do extrato purificado de tanino condensado, realizou-se ensaios anti-helmínticos por meio de testes de desenvolvimento larval (TDL) in vitro de material fecal coletado de caprinos da raça Saanen, naturalmente infectados, sob administração das concentrações nos tratamentos (37,5; 75; 150; 300 e 350 mg/mL) em quatro repetições para cada tratamento de extrato purificado de taninos condensados, acrescidos de tratamento controle, positivo e negativo, com cloridrato de levamisol na concentração de 7,5 mg/mL e água destilada, respectivamente. A Mimosa tenuiflora (Willd) Poiret. se destacou entre as fabaceas nativas com a maior concentração de taninos totais, para todas as frações da planta. Na atividade anti-helmíntica, apresentou efeito significativo, tornando-se uma excelente alternativa no controle de nematódeos gastrintestinais em pequenos ruminantes.
|
Page generated in 0.0447 seconds