Eficácia dos taninos condensados presentes no extrato de acácia no controle de Trichostrongylus colubriformis em ovinos

The aim of this study was to evaluate the potential uses of acacia extract (AE) on Trichostrongylus colubriformis control in sheep. The lambs were allocated in three groups of six animals. Two groups were experimentally infected with third-stage larvae of T. colubriformis and one was remained as non-infected control. Thirty days post-infection, the infected animals from treated group were supplemented with AE. During and after the treatment, the values of faecal eggs counts (FEC), number of third-stage larvae recovered per gram of faeces (LPG), number of FEC accumulated per animal during the treatment period, nematode egg viability, and worm burden were determined. Animals from non-infected group did not presented FEC values, during the experimental period. The average of total accumulated amount of FEC output per group, during the 10 days of the treatment was lower in AE treated lambs (P<0.05). The values of egg viability were statistically reduced (P<0.05) on days 4, 7 and 10 post treatment (p.t.). The number of LPG was lower (P<0.05), at the days 10 and 14p.t., in treated animals. AE showed potential to be used on the prophylaxis of gastrointestinal nematode infections in sheep.O objetivo deste trabalho foi avaliar o potencial do extrato de acácia (EA) para o controle de T. colubriformis em ovinos. Os cordeiros foram alocados em três grupos de seis animais. Dois grupos foram experimentalmente infectados com larvas infectantes de T. colubriformis, sendo um grupo mantido como controle não infectado. Trinta dias pós-infecção, os animais infectados do grupo tratado foram suplementados com EA. Durante e após o tratamento os valores de contagem de ovos por grama de fezes (OPG), número de larvas de terceiro estágio por grama de fezes (LPG), número de OPG eliminado por animal durante o período de tratamento, viabilidade dos ovos e carga parasitária foram determinados. Os animais do grupo não infectado permaneceram com número de OPG igual a zero durante todo o período experimental. A média do número de OPG total eliminado por grupo, somatória durante os 10 dias de tratamento, foi menor nos cordeiros tratados com EA (P<0,05). Os valores de viabilidade dos ovos de helmintos foram menores (P<0,05) nos dias 4, 7 e 10 pós-tratamento (p.t.). O número de LPG foi menor (P<0,05), nos dias 10 e 14p.t., no grupo tratado. O EA demonstrou potencial para sua utilização no controle de T. colubriformis em ovinos

In vitro culture of parasitic stages of Haemonchus contortus = Cultivo in vitro de estádios parasitários de Haemonchus contortus

Haemonchus contortus is a constraint to sheep production. Seeking to reduce the use of hosts and produce parasitic stages in large-scale, a 42-day in vitro culture protocol of H. contortus third-stage larvae was optimized using Dulbecco’s modified Eagle’s medium (DMEM). In cell-free culture, larvae were maintained at 39.6°C, in acidic media (pH 6.1) for 3 or 6 days with Δ4-dafachronic acid followed by DMEM pH 7.4 supplemented or not with Fildes’ reagent. In DMEM pH 7.4 at 37°C, supplementation with Caco-2 cells was compared to Fildes. On Day 14, fourth-stage larvae (L4) development rates in acidic media supplemented (86.8-88.4%) or not (74.4-77.8%) with Fildes and in Caco-2 cell co-culture (92.6%) were similar, and superior to DMEM pH 7.4 with Fildes (0.0%). On Day 21, Caco-2 cell co-culture resulted in higher larvae differentiation (25.0%) and lower degeneration (13.9%) compared to acidic media (1.5-8.1% and 48.6-69.9%, respectively). This is the first report of prolonged in vitro culture of H. contortus larvae using commercial media in co-culture with Caco-2 cells. Although no progression to the adult stage, Caco-2 cell co-culture resulted in morphological differentiation of H. contortus L4 and larval viability for up to 28 days

In vitro efficacy of essential oils against Haematobia irritans

The horn fly (Haematobia irritans) infestation in the cattle in Brazil leads to significant economic damage for livestock. The efficacy of many essential oils has been demonstrated in the control of veterinary ectoparasites. This study aimed to evaluate the in vitro efficacy of four essential oils to adult horn fly control. The essential oil from Mesosphaerum suaveolens (L.) Kuntze (Lamiaceae) was extracted by hydro-distillation, while that the water steam distillation method was used to extract the essential oils from Varronia curassavica (Jacq.) Roem. &amp; Schult. (Boraginaceae), Alpinia zerumbet (Pers.) B.L. Burtt &amp; R.M. Sm. (Zingiberaceae) and Psidium guajava L. (Myrtaceae). Afterwards, all the essential oils were analyzed by Gas Chromatography Mass Spectrometry (GC?MS) and Flame Ionization Detector (GC-FID) for determination of their chemical composition. The bioassays in vitro were performed according to the impregnated filter paper methodology. All the essential oils evaluated in this study exhibited efficacy in vitro against H. irritans. The highest mortality of H. irritans was determined by essential oils from A. zerumbet (100%) and M. suaveolens (96.2%) at 50 mg mL-1. &nbsp;In concentration of 100 mg mL-1 V. curassavica and P. guajava essential oils caused the mortality of 99.2% and 82.8%, respectively. The A. zerumbet, M. suaveolens, V. curassavica and P. guajava essential oils showed in vitro efficacy against H. irritans. Further studies with associations and nanoemultions are necessary to increase the efficacy and stability of these essential oils on field conditions.The horn fly (Haematobia irritans) infestation in the cattle in Brazil leads to significant economic damage for livestock. The efficacy of many essential oils has been demonstrated in the control of veterinary ectoparasites. This study aimed to evaluate the in vitro efficacy of four essential oils to adult horn fly control. The essential oil from Mesosphaerum suaveolens (L.) Kuntze (Lamiaceae) was extracted by hydro-distillation, while that the water steam distillation method was used to extract the essential oils from Varronia curassavica (Jacq.) Roem. &amp; Schult. (Boraginaceae), Alpinia zerumbet (Pers.) B.L. Burtt &amp; R.M. Sm. (Zingiberaceae) and Psidium guajava L. (Myrtaceae). Afterwards, all the essential oils were analyzed by Gas Chromatography Mass Spectrometry (GC?MS) and Flame Ionization Detector (GC-FID) for determination of their chemical composition. The bioassays in vitro were performed according to the impregnated filter paper methodology. All the essential oils evaluated in this study exhibited efficacy in vitro against H. irritans. The highest mortality of H. irritans was determined by essential oils from A. zerumbet (100%) and M. suaveolens (96.2%) at 50 mg mL-1. In concentration of 100 mg mL-1 V. curassavica and P. guajava essential oils caused the mortality of 99.2% and 82.8%, respectively. The A. zerumbet, M. suaveolens, V. curassavica and P. guajava essential oils showed in vitro efficacy against H. irritans. Further studies with associations and nanoemulsions are necessary to increase the efficacy and stability of these essential oils on field conditions

Degree of technification of the sheep herd may be associated with seropositivity for the maedi-visna virus In South Brasil

Maedi-Visna (MV) is a chronic progressive multisystem disease that may be asymptomatic for several months or years, but progress rapidly, and may result in death, when signs and symptoms evolve. Viral elimination occurs mainly through direct contact with positive animal secretions. There is no vaccine or treatment, and prophylaxis is necessary for the health of the herd. The present study aimed to verify the seropositivity of MV and evaluate the factors associated with the risk in sheep herds in Paraná. A total of 1549 serum samples were collected from 90 properties. An epidemiological questionnaire was applied to each property, and the variables were analyzed using the Epi-info program and R environment. Of the 1549 samples analyzed, 22 were positive (1.4%) for the micro-AGID test in 13.3% of the properties. Our study demonstrated variables associated with the prevention and the risk of seropositivity to MVV. Conducting a breeding season, supplying concentrated feed, and separating the breeding stock before birth were factors associated with protection, whereas the previous occurrence of problems with lice, breeding on pasture, and keeping cats close to the flock were factors associated with risk. The seropositivity observed in the present study suggests the circulation of MVV in sheep herds in Paraná, which reinforces the need to implement prevention and control measures since the level of technification may be associated with the occurrence of anti-MVV antibodies in herds

Anthelmintic effect of condensed tannins on gastrointestinal nematodes in sheep

As helmintoses gastrintestinais estão entre as principais enfermidades na criação de ovinos, sendo importante causa de mortalidade e de redução na produtividade dos animais. O controle das infecções por nematódeos é baseado no uso de drogas anti-helmínticas, porém com a descrição emergente de parasitos resistentes, a eficácia deste tratamento tem diminuído. Portanto, métodos alternativos de controle são necessários para a diminuição ou, até mesmo, a substituição do uso de drogas para o controle das verminoses em pequenos ruminantes. O uso dos taninos condensados (TC) no controle das helmintoses gastrintestinais de ovinos em todo o mundo tem se mostrado promissor. Este trabalho teve como objetivo avaliar o efeito anti-helmíntico dos TC sobre nematódeos gastrintestinais de ovinos. Durante o período de testes foram realizados quatro ensaios experimentais: ensaio A avaliação in vitro da ingestão por larvas de primeiro estágio (L1) de Haemonchus contortus, Trichostrongylus colubriformis e Teladorsagia circumcincta, para avaliar o efeito anti-helmíntico dos TC provenientes do extrato de acácia (Acacia mearnsii); ensaio B estudo sobre a infecção natural dos cordeiros a campo, animais infectados com H. contortus e T. colubriformis, sendo os mesmos divididos em dois grupos (tratados com extrato de acácia e não tratados); ensaios C e D realizados com infecção experimental dos animais por nematódeos gastrintestinais (H. contortus e T. colubriformis, respectivamente). Nos dois últimos ensaios, os animais foram divididos em cinco grupos, sendo: GI (controle infectado com nematódeo); GII (recebeu sorgo taninífero); GIII (recebeu extrato de acácia uma vez ao dia); GIV (recebeu extrato de acácia duas vezes ao dia) e GV (controle não infectado). Os resultados dos ensaios A (ingestão larval) e B (infecção natural) foram promissores e demonstraram o efeito direto dos TC sobre os nematódeos parasitas de ovinos, com diferença significativa (P 0,05), porém no experimento com infecção por T. colubriformis (ensaio D) foi evidenciada diferença (P 0.05), however the T. colubriformis experimental infection results (experiment D) showed significant difference (P < 0.01) on EPG values of sheep supplemented with sorghum (GI) and drenched with CTE for two days (GIV), when compared with infect control (GI); Significant reduction of female worm burden was demonstrated between GI and GIV (P < 0.01) on experiment D. Reduction on nematode egg viability (from eggs to L1) and infective larvae (L3) from coprocultures made with faeces from CT treated groups were observed in experiments C and D. The results evidenced the direct action of CT on sheep gastrointestinal nematodes and mainly on L3 production; however more studies are necessary to indicate a strategic alternative parasite control based in CT source

Anthelmintic effect of condensed tannins in gastrointestinal nematodes of sheep (Ovis aries)

Gastrointestinal helminthiasis infections are considerate one of the main limiting factors in sheep production worldwide. The development of parasite resistance to anthelmintics has caused significant losses of small ruminant production. In the search for new alternatives for effective control of gastrointestinal nematodes in small ruminants, phytotherapy is a promising field of research in an attempt to reduce the usage of chemical treatments, aimed at ecological production. Many plants play a crucial role in maintaining animal and human life. During human evolution many interactions with other organisms were established and they have affected each other in many ways. Plants have developed biochemical mechanisms to defend themselves from biological antagonists that act as their natural enemies. This principle has led scientists to search for bio-active compounds produced by plants against pathogens. Since these discovers their metabolites are evaluated against diseases of importance not only in public health, but also in animal production. This article presents a review of studies with tanniniferous plants scientifically tested worldwide for the control of gastrointestinal parasites in ruminants

Longitudinal data analysis in animal experiments<br>Análise de dados longitudinais em experimentação animal

Longitudinal data analysis with repeated measures over time can be done in different ways: in experiments using the split plot design, with the animal as plots and time as subplots; through the analysis of multivariate models; and also by adjusting mixed models, which enables the use of different structures for the covariance matrix. The main problem involved in the analysis of repeated measures over time is related to the lack of randomization, because pairs of measurements taken along the time are correlated, which can invalidate the tests involving the time factor. To discuss the different forms of analysis, data were used from an experiment in which Santa Ines lambs were infected with 6,000 L3 Haemochus contortus and treated with condensed tannin. The source of tannin was the acacia extract obtained from Acacia mearnsii (commercially available). The data were analyzed using the software R 2.11.1 (2010). No significant effect was found (p > 0.05) of supplementation with tannin, acting on the body weight of animals. The methods used for data analysis showed similar results, which does not always occur. And considering the dependence of observations taken over time, recommended the setting of mixed models, which may involve growth curves or polynomial models that include the covariance matrix that best explains the data.<P><P>A análise de dados longitunais com medidas repetidas ao longo do tempo pode ser feita de diferentes maneiras: em experimentos usando o delineamento em parcelas subdivididas, tendo o animal como parcela e o tempo como subparcela; através da análise de modelos multivariados; e ainda através do ajuste de modelos mistos, que possibilita a utilização de diferentes estruturas para a matriz de covariâncias. O principal problema envolvido na análise de medidas repetidas ao longo do tempo está relacionado à ausência de aleatorização, pois pares de mensurações feitas no tempo estão correlacionadas, o que pode invalidar os testes envolvendo o fator tempo. Para discutir as diferentes formas de análise, foram utilizados dados provenientes de um experimento em que cordeiros Santa Inês foram infectados com 6.000 L3 de Haemochus contortus e tratados com tanino condensado. A fonte do tanino foi o extrato de acácia proveniente da Acacia mearnsii (produto comercial). Os dados foram analisados através do software livre R 2.11.1 (2010). Não foi encontrado efeito significativo (p > 0,05) da suplementação com extrato de acácia sobre o peso vivo dos animais. As metodologias utilizadas para a análise dos dados apresentaram resultados semelhantes, o que nem sempre ocorre. E, considerando a dependência das observações obtidas ao longo do tempo, recomenda-se o ajuste de modelos mistos, que podem envolver curvas de crescimento ou modelos polinomiais que incluam a matriz de covariâncias que melhor explique o comportamento dos dados

Efficacy of condensed tannin presents in acacia extract on the control of Trichostrongylus colubriformis in sheep Eficácia dos taninos condensados presentes no extrato de acácia no controle de Trichostrongylus colubriformis em ovinos

The aim of this study was to evaluate the potential uses of acacia extract (AE) on Trichostrongylus colubriformis control in sheep. The lambs were allocated in three groups of six animals. Two groups were experimentally infected with third-stage larvae of T. colubriformis and one was remained as non-infected control. Thirty days post-infection, the infected animals from treated group were supplemented with AE. During and after the treatment, the values of faecal eggs counts (FEC), number of third-stage larvae recovered per gram of faeces (LPG), number of FEC accumulated per animal during the treatment period, nematode egg viability, and worm burden were determined. Animals from non-infected group did not presented FEC values, during the experimental period. The average of total accumulated amount of FEC output per group, during the 10 days of the treatment was lower in AE treated lambs (PO objetivo deste trabalho foi avaliar o potencial do extrato de acácia (EA) para o controle de T. colubriformis em ovinos. Os cordeiros foram alocados em três grupos de seis animais. Dois grupos foram experimentalmente infectados com larvas infectantes de T. colubriformis, sendo um grupo mantido como controle não infectado. Trinta dias pós-infecção, os animais infectados do grupo tratado foram suplementados com EA. Durante e após o tratamento os valores de contagem de ovos por grama de fezes (OPG), número de larvas de terceiro estágio por grama de fezes (LPG), número de OPG eliminado por animal durante o período de tratamento, viabilidade dos ovos e carga parasitária foram determinados. Os animais do grupo não infectado permaneceram com número de OPG igual a zero durante todo o período experimental. A média do número de OPG total eliminado por grupo, somatória durante os 10 dias de tratamento, foi menor nos cordeiros tratados com EA (P<0,05). Os valores de viabilidade dos ovos de helmintos foram menores (P<0,05) nos dias 4, 7 e 10 pós-tratamento (p.t.). O número de LPG foi menor (P<0,05), nos dias 10 e 14p.t., no grupo tratado. O EA demonstrou potencial para sua utilização no controle de T. colubriformis em ovinos

Efeito anti-helmíntico de taninos condensados sobre Trichostrongylus colubriformis em ovinos experimentalmente infectados

Recent surveys have identified anthelmintic effects from many bioactive substances particularly from condensed tannin (CT) sources. The aims of the present study were to investigate the potential anthelmintic effects of condensed tannins (CT) on Trichostrongylus colubriformis in experimentally infected sheep and the nutritional consequences on animals. Twenty helminth-free lambs were divided into five groups of four animals. Groups I to IV were artificially infected with 6,000 third stage larvae (L3) of T. colubriformis. Group I was the infected control and group V was the uninfected control. Twenty-eight days post-infection (p. i.) lambs from GII were supplemented with tanniniferous sorghum (350 g/animal/day, during seven days); GIII were drenched with Acacia mearnsii extract (15% CT) for just one day and GIV during two days (1.6 g extract/kg BW). At day 36 p. i., animals from infected group (GI to GIV) were slaughtered. Faecal egg counts (FEC) values present a reduction on GII when compared with GI at day 29 p. i. (P 0.05). No difference was related on total worm burden between treatments; however, GIV presented lower number of females than GI (P 0,05). O uso dos TC pode ser promissor no controle de T. colubriformis em ovinos.