In vitro effects of three woody plant and sainfoin extracts on two parasitic stage of 3 parasitic nematode species

Most studies on the effects of tanniferous plants on nematodes have examined forages but have neglected the woody plants. Therefore, in vitro effects of extracts from 3 woody plants (Rubus fructicosus, Quercus robur, Corylus avellana) have been tested on trichostrongyles and compared to sainfoin, a legume forage. Because some in vivo results indicated that the effects of tannins differed depending on the parasitic species and/or stages, the effects were measured on third-stage larvae (L3) and adult worms of Teladorsagia circumcincta, Haemonchus contortus and Trichostrongylus colubriformis. The effects of plant extracts varied according to the plant sources, the parasite species and stages. For the woody plants, significant inhibitory effects were obtained on both stages of abomasal species. Results for T. colubriformis were more variable. Effects of sainfoin extracts were significant on T. colubriformis and H.contortus L3, and on abomasal adult worms. In order to assess the implications of tannins, polyethylene glycol (PEG), an inhibitor of tannins, was added to hazel tree, oak and sainfoin extracts. Without PEG, significant inhibitory effects on L3 and adult worms were confirmed. After addition of PEG, the larval migration and motility of adult worms were restored in most cases. These results confirm variations in effects depending on factors related to plants or parasites and suggest that tannins are partly responsible for the effects

Effects of sainfoin hay on gastrointestinal infection with nematodes in goats

EFFECTS OF SAINFOIN HAY ON GASTROINTESTINAL INFECTION WITH NEMATODES IN GOATS

Effect of bioactive compounds from Sainfoin (Onobrychis viciifolia Scop.) on the in vitro larval migration of Haemonchus contortus: role of tannins and flavonol glycosides

Anthelmintic bioactivity against gastrointestinal nematodes has been associated with leguminous forages supporting the hypothesis of a role of condensed tannins. However, the possibility that other compounds might also been involved has received less consideration. Using bio-guided fractionation, the current study aimed at characterising the biochemical nature of the active compounds present in sainfoin (Onobrychis viciifolia), previously identified as an anthelmintic leguminous forage. The effects of sainfoin extracts were evaluated on 3rd stage larvae (L3) of Haemonchus contortus by using a larval migration inhibition (LMI) assay. Comparison of extracts obtained with several solvent systems showed that the bioactivity was associated with the 70:30 acetone/water extract. Further fractionation of the later allowed the separation of phenolic compounds. By use of a dialysis method, compounds were separated with a molecular weight cut-off of 2000 Da. The in vitro anthelmintic effects of the fraction with condensed tannins was confirmed. In the fraction containing molecules of MW < 2000 Da, 3 flavonol glycosides were identified as rutin, nicotiflorin and narcissin. At 1200 μg/ml, each inhibited significantly migration of larvae. Addition of polyvinyl pyrrolidone (PVPP) to both fractions before incubation restore larval migration. These results confirmed the role of both tannins and flavonol glycosides in the anthelmintic properties of sainfoin

Effects of the repeated distribution of sainfoin hay on the resistance and the resilience of goats naturally infected with gastrointestinal nematodes

Due to the high prevalence of anthelmintic resistance in goats, the need to explore novel approaches to control nematodes and to reduce the exclusive reliance on chemotherapy is strongly demanded in this host species. In sheep, several studies have shown that the consumption of tannin-rich legume forages was associated with positive effects on host resilience and resistance to parasite infection. In goats, studies on such interactions between tanniferous plants and nematode infections remain few. The objectives of the current study were to examine under natural conditions the effects of consumption of sainfoin hay by goats on the parasite populations and on host resilience. Eighteen adult cull goats naturally infected with Haemonchus contortus, Teladorsagia circumcincta and Trichostrongylus colubriformis were used in the study. At the start of the assay, the goats were allocated into two groups, balanced according to weight and the levels of egg excretion. The two groups grazed separate pastures for 3 months with similar stocking rates. Goats from group S received each month indoors, for 7 days, sainfoin hay and control goats (group C) received hay of ryegrass. The diets in both groups were made isoenergetic and isoproteic and the refusals measured. Individual parasitological and pathophysiological measurements were performed fortnightly in order to compare host resistance and resilience. At the end of the study, five goats per group were necropsied. The distribution of sainfoin was associated with: (1) a higher consumption of hay; (2) significant, lower levels of nematode egg excretion which was associated with a decrease in worm fertility but no change in worm population; however, the number of intestinal worms was reduced by 50% in group S; (3) a better host resilience. In particular, after 2 months of grazing, two control goats died and half of the remaining animals needed to be treated whereas this was not the case in group S. These differences were related to significant changes in pepsinogen and phosphate values (PCV) but not in pepsinogen and phosphate concentrations. These results demonstrate that a repeated distribution of sainfoin hay to grazing goats might be beneficial in regard of pasture contamination and host resilience. They suggest that administration of sainfoin hay might represent a valuable alternative and adjunct to reduce nematode infections in dairy goat flock. # 2004 Elsevier B.V. All rights reserved

Effects of condensed tannins on goats experimentally infected with Haemonchus contortus.

Although the use of tanniferous plants or condensed tannins as an alternative to anthelmintics to control gastrointestinal nematodes has been largely documented in sheep, studies remain scarce in goats. The objective of this study was therefore to assess the possible impact of condensed tannins in goats infected with adult Haemonchus contortus. Two groups of cull goats were experimentally infected with 10.000 L3 of H. contortus. After 4 weeks, quebracho extracts, representing 5% of the diet DM, were administered for 8 days to one of the two groups. Goats of the second group remained as controls. One week after the end of quebracho administration, the goats were euthanised. Individual egg excretion and pathophysiological parameters were measured weekly during the study. At the end of the study, worm counts were assessed and histological samples from the abomasa were taken to count the numbers of mucosal mast cells, globule leukocytes and eosinophils. The administration of tannins was associated with a significant decrease in egg excretion, which persisted until the end of experiment. This reduction was not associated with any difference in worm number but with a significant decrease in female fecundity. No significant changes in the mucosal density of the three inflammatory cell types were detected between the two groups. These results indicate that the major consequence of tannin consumption in goats is a reduction in worm fecundity and egg output, which does not seem related to significant changes in the local mucosal response

Construction d une problématique et d’un partenariat sur la gestion du parasitisme lie au pâturage en élevage caprin en agriculture biologique

Construction d'une problématique et d’un partenariat sur la gestion du parasitisme lié au pâturage en élevage caprin en agriculture biologique

Effets des tanins condensés et des plantes à tanins sur les strongyloses gastro intestinales chez le mouton et la chèvre

Les strongyloses gastro-intestinales sont une des pathologies majeures chez les petits ruminants élevés à l’herbe. Elles peuvent entraîner des pertes de production importantes. Le moyen usuel de lutte contre ces parasitoses est l’utilisation des anthelminthiques. Cependant, plusieurs problèmes se posent quant à leur utilisation. Premièrement, les résistances aux anthelminthiques au sein des populations de vers sont de plus en plus fréquentes, et particulièrement chez les caprins. Deuxièment, en lactation, seules certaines molécules sont autorisées. De plus, les consommateurs se montrent de plus en plus réticents à l’emploi de molécules chimiques en élevage. Il y a donc un réel besoin de trouver des méthodes alternatives ou complémentaires aux anthelminthiques afin de maîtriser ce parasitisme digestif. L’utilisation de champignons nématophages, une gestion raisonnée du pâturage ou encore un apport de protéines au sein de l’alimentation sont des méthodes pouvant aider à mieux gérer les infestations parasitaires. Une autre solution alternative envisageable est l’emploi des tanins condensés. Différentes études menées chez les ovins et les caprins montrent que l’apport de tanins condensés pourrait constituer un moyen de lutte efficace contre les strongles gastro-intestinaux

Meta-Learning for Phonemic Annotation of Corpora

We apply rule induction, classifier combination and meta-learning (stacked classifiers) to the problem of bootstrapping high accuracy automatic annotation of corpora with pronunciation information. The task we address in this paper consists of generating phonemic representations reflecting the Flemish and Dutch pronunciations of a word on the basis of its orthographic representation (which in turn is based on the actual speech recordings). We compare several possible approaches to achieve the text-to-pronunciation mapping task: memory-based learning, transformation-based learning, rule induction, maximum entropy modeling, combination of classifiers in stacked learning, and stacking of meta-learners. We are interested both in optimal accuracy and in obtaining insight into the linguistic regularities involved. As far as accuracy is concerned, an already high accuracy level (93% for Celex and 86% for Fonilex at word level) for single classifiers is boosted significantly with additional error reductions of 31% and 38% respectively using combination of classifiers, and a further 5% using combination of meta-learners, bringing overall word level accuracy to 96% for the Dutch variant and 92% for the Flemish variant. We also show that the application of machine learning methods indeed leads to increased insight into the linguistic regularities determining the variation between the two pronunciation variants studied.Comment: 8 page

Consequences of the regular distribution of sainfoin hay on gastrointestinal parasitism with nematodes and on milk production in a dairy goat flock

The objectives of the current study were to examine the potential effects of distribution of sainfoin hay on nematode parasitism in a producing herd and to measure the consequences on milk production. The survey was performed in an experimental herd of 120-dairy-goat farm during a whole 9-month grazing season. Every month, 60 goats received indoors on average 1.36 kg of sainfoin hay for 10 days whereas the 60 remaining goats were used as controls, thus receiving the same amount of lucerne hay at the same time. The nutritional values of both hays were comparable except that concentrations of condensed tannins was higher in sainfoin than in lucerne hay, i.e. 2.52% versus 0.7% of diet DM. Intakes of the two types of hay were recorded along with each period. Individual faecal and blood samples were performed monthly to compare parasitological and pathophysiological parameters in the two groups. Milk yield, fat and protein contents were measured fortnightly. A higher consumption of hay was repeatedly recorded in the sainfoin versus the control group. Irrespective to dietary treatment, nematode egg excretions were low during the whole season. Meanwhile, egg output was significantly lowest in the sainfoin group, but the composition in nematode genera was similar among the two groups. Based on a semi quantitative index for assessment of faecal consistency, a lower faecal dry matter content was also found in goats from the sainfoin group. The two animal groups exhibited similar milk yield, fat and protein contents. The differences in egg excretion between the two groups might be due to higher intake of hay in the barn thus to low consumption of grass, a source of parasite infection, or to the effect of some secondary compounds, like tannins. Whatever the mechanism involved, our results suggest that a regular distribution of sainfoin hay to dairy goats might be associated with a reduction in parasitism with gastrointestinal nematodes, without negative consequences on milk production. © 2005 Elsevier B.V. All rights reserved

Effects of distribution of quebracho extracts on experimental Haemonchus contortus infections in goats

The effects of tannins on adult populations of Haemonchus contortus, Trichostrongylus colubriformis and Teladorsagia circumcincta in goats are characterised mainly by a decrease in egg excretion without any significant changes in worm number. In contrast, the impact of tannins on T. colubriformis or T. circumcincta third-stage larvae (L3) is associated with a significant reduction in worm establishment. The objective of the present study was to examine the effects of quebracho extract tannins on H. contortus L3. The consequences of consumption of sainfoin hay were also examined. Twenty-one naı¨ve kids were divided into three experimental groups. Group Q received quebracho extract and group S received sainfoin hay from days D3 to D5. Group C remained as an infected control group. All kids received 1500 L3 H. contortus on D0, D1 and D2. On D18, post-infection, the kids were slaughtered and the worm populations compared in the different groups. Compared to the control values, the worm counts decreased, respectively, by 33% and 38% in groups Q and S but the differences were not significant. No differences were found in pathophysiological measurements between the three groups. The results confirm differences in tannin effect according to nematode species but not parasitic stage