Effects of condensed tannins on goats experimentally infected with Haemonchus contortus

Research on the Control of Gastrointestinal Strongyles in Sheep by Using Lotus corniculatus or Cichorium intybus in Feed

The general practice of sheep farmers in gastrointestinal helminth control is based on the use of commercial drugs, making chemoresistance very common. Considering this, our study focused on the biological control of gastrointestinal parasitism using high-tannin plant hay. Three groups of 30 animals each were formed. The control group was additionally fed meadow hay, while the other two groups received chicory (group 2) and bird's foot trefoil hay (group 3). The number of gastrointestinal strongyle eggs, shed through faeces (EPG), was surveyed for 28 days for all animals. The amounts of total tannins for meadow, chicory, and Lotus corniculatus hay supplements were 13.92 mg/g, 78.59 mg/g, and 94.43 mg/g, while their condensed tannin contents were 2.58 mg/g, 29.84 mg/g, and 15.94 mg/g, respectively. Compared to experimental day 0, there was an increase in EPG of 80.83% in the control group, a decrease of 24.72% in group 2, and a 20% decrease in group 3, by day 28. The p-value was <0.05 between group 1 and the other groups, showing significant differences between the control and experimental groups. The decrease in EPG rates in the experimental groups compared to the control group demonstrates an antiparasitic effect of Lotus corniculatus and chicory.

Managing Encapsulated Oil Extract of Date Seed Waste for High Hydroxyl Radical Scavenging Assayed via Hybrid Photo-Mediated/Spectrofluorimetric Probing

This work addresses two research topics: the first concerns the specific/sensitive trapping of hydroxyl radicals (^•OH), and the second concerns the efficacy of encapsulating natural antioxidants, potentially lengthening their preservation activity. For context, nano-titania was solar-irradiated to produce ^•OH, which was spectrofluorimetrically assessed, based on the selective aromatic hydroxylation of the non-fluorescent sodium terephthalate to 2-hydroxyterephthalate fluorophore. Fluorescence intensity is proportional to generated ^•OH. Thus, a simple/rapid indirect method was utilized to assess ^•OH precisely. Accordingly, novel photoluminescent system is outlined in order to assess the scavenging potentiality of ^•OH in date seed oil (DSO) in both its pure and encapsulated formulations (ECP-DSO), i.e., when fresh and 5 months after extraction and encapsulation, respectively. With the addition of 80 μg/mL DSO or ECP-DSO, the efficacy of ^•OH scavenging amounted to 25.12 and 63.39%, which increased to 68.65 and 92.72% when 200 μg/mL DSO or ECP-DSO, respectively, was added. Moreover, the IC50 of DSO and ECP-DSO is 136.6 and 62.1 µg/mL, respectively. Furthermore, DSO and ECP-DSO decreased the kinetics for producing ^•OH by ≈20 and 40%, respectively, relative to ^•OH generated in the absence of antioxidant. This demonstrates the benefits of encapsulation on the preservation activity of natural antioxidants, even after five months after extraction, in terms of its interesting activity when compared to synthetic antioxidants. The developed fluorimetric ^•OH probing upgrades antioxidant medicines, thus paving the way for theoretical/practical insights on mechanistic hydroxyl radical-damaging biology.

Antiparasitic Tannin-Rich Plants from the South of Europe for Grazing Livestock: A Review

Internal parasites are one of the main causes of health threats in livestock production, especially in extensive livestock farming. Despite the environmental toxic effects (loss of dung beetles, biodiversity, and other issues) and resistance phenomenon derived from their prolonged use, anti-parasitic chemical pharmaceuticals are frequently used, even in organic farming. Such a situation within the context of climate change requires urgent exploration of alternative compounds to solve these problems and apparent conflicts between organic farming objectives regarding the environment, public health, and animal health. This review is focused on some plants (Artemisia spp., Cichorium intybus L., Ericaceae family, Hedysarum coronarium L., Lotus spp., Onobrychis viciifolia Scop.) that are well known for their antiparasitic effect, are voluntarily grazed and ingested, and can be spontaneously found or cultivated in southern Europe and other regions with a Mediterranean climate. The differences found between effectiveness, parasite species affected, in vitro/in vivo experiments, and active compounds are explored. A total of 87 papers where antiparasitic activity of those plants have been studied are included in this review; 75% studied the effect on ruminant parasites, where gastrointestinal nematodes were the parasite group most studied (70%), and these included natural (31%) and experimental (37%) infections.

Use of agro-industrial by-products containing tannins for the integrated control of gastrointestinal nematodes in ruminants

Previous studies have illustrated that different bioactive legume fodders containing condensed tannins might represent one of the options for integrated sustainable control of gastrointestinal nematodes (GIN) in ruminants, which may help address the worldwide development of resistance to synthetic anthelmintics. More recently, impetus has been given to assess the potential antiparasitic activity of less conventional resources, represented by different agro-industrial by-products (AIBPs). This review presents in vitro and in vivo results obtained with a range of tannin-containing AIBPs of various geographical and botanical origins, namely AIBP of nuts, temperate and tropical barks, carob, coffee and cocoa. They tend to confirm the “proof of concept” for their antiparasitic effects and also for other aspects of ruminant production in an agro-ecological context. Socio-economic aspects of the exploitation of such non-conventional resources are also discussed as potential models of the circular economy, by using waste. The different modes of use of these resources are presented in this review, as well as strengths, weaknesses, opportunities, and threats (SWOT) analyses to illustrate the advantages and limitations of on-farm use.

The effect of pumpkin seed cake and ground cloves (Syzygium aromaticum) supplementation on gastrointestinal nematode egg shedding in sheep

The aim of this study was to evaluate the effect of feed additives (pumpkin seed cake and cloves) on the egg excretion of gastrointestinal nematodes (GIN) in sheep. Thirty ewes naturally infected with GIN were randomly selected from a flock and assigned to the following groups of 10 animals each: clove group (received 1.8 g ground cloves/ewe/day, for 7 days), pumpkin seed cake group (200 g pumpkin seed cake/ewe/day, for 7 days) and control group. Before starting the study, on day 0, and 5 days after the 7-day supplementation, on day 12, the body condition and FAMACHA scores were assessed and individual faecal egg counts (FEC) were performed. The mean body condition and the FAMACHA scores did not change significantly between day 0 and 12 with the exception of a significantly deteriorated FAMACHA score in the clove group. The percentage reduction of FEC was 40.7% on day 12 in the clove group and 52.9% in the pumpkin seed cake group. In the control group, FEC increased by 8.7%. A coproculture of faecal samples from four of the most infected animals on day 0 revealed Trichostrongylus spp. larvae L3 in all four selected ewes, Ostertagia spp. and Cooperia spp. in three and Haemonchus contortus in one ewe. These results are promising and encourage further studies aimed to evaluate the possibility that these plant supplements could be a complementary method for parasite control, thus reducing the need for chemotherapy.

Eficacia antiparasitaria in vitro del extracto de quebracho (Schinopsis balansae) sobre larvas infectantes de Haemonchus contortus de ovinos

El objetivo fue evaluar in vitro la eficacia del extracto de quebracho (Bioquina®), rico en taninos condensados, en el control de H. contortus de ovinos, dadas las evidencias de que los taninos condensados provenientes del extracto de quebracho (Schinopsis spp.) pueden reducir la excreción de huevos, la fecundidad de las hembras parásitas y la carga de parásitos nematodos gastrointestinales adultos en rumiantes. Se utilizó el test de inhibición de migración larval (IML) a 3 concentraciones diferentes (5 mg/ml, 15 mg/ml y 30 mg/ml) sobre larvas infectantes de H. contortus susceptibles a todos los grupos químicos. El efecto se analizó mediante un análisis de varianza y para la estimación de las diferencias entre grupos (a posteriori) se usó la prueba LSD Fisher. El test in vitro demostró que el extracto de quebracho evaluado redujo aproximadamente entre un 74% y un 80% la migración larval a las concentraciones de entre 5 mg/ml y 30 mg/ml. Del análisis de varianza surgen diferencias significativas entre tratamientos (p = 0,0494). Al realizar la prueba de comparación de medias se evidenciaron diferencias significativas (p < 0,05) entre los promedios de migración a las diluciones de 5 mg/ml y 15 mg/ml y de 5 mg/ml y 30 mg/ml, mientras que no se detectaron diferencias significativas entre la dilución de 15 mg/ml y 30 mg/ml. Estos resultados señalaron que el extracto de quebracho, a las diluciones evaluadas, presentó actividad antihelmíntica sobre larvas L3 susceptibles de H. contortus; sin embargo, se requiere ampliar los estudios in vivo en ovinos.

Effect of Artemisia absinthium and Malva sylvestris on Antioxidant Parameters and Abomasal Histopathology in Lambs Experimentally Infected with Haemonchus contortus

This study evaluated the effect of Artemisia absinthium and Malva sylvestris on antioxidant response and histopathological changes in the abomasa of the Haemonchus contortus infected lambs. Twenty-four lambs were divided into four groups: unsupplemented lambs (UNS), lambs supplemented with A. absinthium (ART), lambs supplemented with M. sylvestris (MAL), and lambs supplemented with both plants (ARTMAL). Lambs were infected orally with approximately 5000 third-stage (L3) larvae of H. contortus. The experiment was conducted for 75 d (days), all animals were then slaughtered; and the abomasal tissues were examined for antioxidant parameters and histopathology. The concentration of malondialdehyde in the abomasal mucosa was lower in ARTMAL (p < 0.05), and the total antioxidant capacity was higher in MAL (p < 0.05), than in UNS. Increased mucus production was observed in the ARTMAL. The number of mast cells in UNS and ART was significantly higher than the number in MAL (p < 0.01 and p < 0.05). Plasma cell numbers were higher in ARTMAL than the number in MAL (p < 0.05). Abomasal tissue regenerated more frequently in ARTMAL. These results represent the first report of the impact of A. absinthium and M. sylvestris on antioxidant parameters and local immune responses of abomasal mucosa of lambs infected with a GIN parasite.

Advances in the discovery and development of anthelmintics by harnessing natural product scaffolds

Widespread resistance to currently-used anthelmintics represents a major obstacle to controlling parasitic nematodes of livestock animals. Given the reliance on anthelmintics in many control regimens, there is a need for the continued discovery and development of new nematocides. Enabling such a focus are: (i) the major chemical diversity of natural products; (ii) the availability of curated, drug-like extract-, fraction- and/or compound-libraries from natural sources; (iii) the utility and practicality of well-established whole-worm bioassays for Haemonchus contortus-an important parasitic nematodes of livestock-to screen natural product libraries; and (iv) the availability of advanced chromatographic (HPLC), spectroscopic (NMR) and spectrometric (MS) techniques for bioassay-guided fractionation and structural elucidation. This context provides a sound basis for the identification and characterisation of anthelmintic candidates from natural sources. This chapter provides a background on the importance and impact of helminth infections/diseases, parasite control and aspects of drug discovery, and reviews recent work focused on (i) screening well-defined compound libraries to establish the methods needed for large-scale screening of natural extract libraries; (ii) discovering plant and marine extracts with nematocidal or nematostatic activity, and purifying bioactive compounds and assessing their potential for further development; and (iii) synthesising analogues of selected purified natural compounds for the identification of possible 'lead' candidates. The chapter describes some lessons learned from this work and proposes future areas of focus for drug discovery. Collectively, the findings from this recent work show potential for selected natural product scaffolds as candidates for future development. Developing such candidates via future chemical optimisation, efficacy and safety evaluations, broad spectrum activity assessments, and target identification represents an exciting prospect and, if successful, could pave the way to subsequent pre-clinical and clinical evaluations.

Quebracho tannins aid in the control of Eimeria spp. and gastrointestinal nematodes in lambs and goat kids

The objective was to examine the effects of supplementary quebracho on control of coccidiosis and gastrointestinal nematodes in lambs and kids. In Exp. 1, naturally infected lambs weaned (87.8 ± 0.4 days of age; day 0) in January (winter) were blocked by sex and randomly assigned (n = 10/treatment) to receive supplement with or without 100 g/lamb of quebracho for 28 days. In Exp. 2, single or twin rearing ewes were randomly assigned into two groups, and naturally infected lambs were fed control (n = 28) or quebracho (100 g/lamb of quebracho tannins in feed; n = 27) between -28 and 21 days (weaning = day 0; 70.8 ± 0.1 days of age). In Exp. 3, weaned doe kids (57.6 ± 2.0 days of age) were randomly assigned to receive alfalfa (Medicago sativa) supplement with (n = 9) or without (n = 8) 50 g/kid quebracho or sericea lespedeza (Lespedeza cuneata) with quebracho (n = 8) for 21 days. Fecal oocyst count (FOC), nematode egg counts (FEC), fecal score, dag score (soiling around rear quarters), and blood packed cell volume (PCV) were determined every 7 days. Data were analyzed as repeated measures using mixed models. In Exp. 1, FOC decreased in quebracho-fed lambs (diet × time, P < 0.001) but FEC was similar between treatments during the feeding period (P = 0.19). Packed cell volume (P = 0.19) and fecal score (P = 0.42) were similar between groups. Quebracho-fed lambs had a greater dag score initially (diet × time, P = 0.02), but were similar by day 42 (P = 0.72). In Exp. 2, FOC remained low (P = 0.02), PCV tended to decrease (P = 0.06), but FEC increased on days 14 and 21 (diet × time; P < 0.001) in quebracho compared with control-fed lambs. Quebracho-fed lambs had lower fecal score (diet × time; P = 0.005) but higher dag score (diet × time; P < 0.001). In Exp. 3, FOC of kids fed quebracho (alfalfa or sericea lespedeza supplement) was lower than control (P < 0.001). Fecal score of kids fed sericea lespedeza compared with alfalfa were lower regardless of quebracho (P = 0.01). There were no differences among treatments for dag, FEC, PCV, or body weight (P> 0.10). Quebracho was effective in reducing FOC but not clinical signs of coccidiosis in both lambs and kids, and may not be highly digestible in lambs as it caused loose stools.

The Potential Effect of Dietary Tannins on Enteric Methane Emission and Ruminant Production, as an Alternative to Antibiotic Feed Additives – A Review

Antibiotic growth promoters in livestock nutrition cause microbial resistance which produces threats to human health. Therefore, tannins have been considered as natural alternative antibiotic feed additives which possess various biological properties including antimicrobial, anti-inflammatory, antioxidant and immunomodulatory. Additionally, these plants also have antiparasitic and anti-bloat characteristics which contribute to inhibit the enteric methane emission in order to improve nutrient digestibility, milk and meat quality, fatty acids composition and ruminant production. Antibiotic growth promoters have been practiced in animals feeding to increase feed intake, growth rate, weight gain as well as reduce metabolic disorders and energy losses in the rumen. In 2006, the European Union banned the usage of antibiotic growth promoters in the feeding of livestock. This antibiotic resistance issue has increased demand to explore the natural feed additives that might be useful for animal production system. Consequently, natural forages have been categorized as potential feed additives in animal production since it improves nutritive value, protein digestibility, increase amino acid absorption and growth rate. But, some plant materials are usually rich in tannins known as anti-nutritional factors. Therefore, the application of tannin-rich plants in ruminant nutrition needs great precaution due to its possible injurious effects (dose dependent) on animal health such as metabolic disorders. Hence, there is need to give attention to the usage of tannins in ruminant nutrition as an alternative to antibiotics feed additives to investigate its effects on enteric methane emissions and ruminants production. In addition, safety and risk associated with tannins feeding have also been briefly discussed.

Ultrastructural study of adult Haemonchus contortus exposed to polyphenol-rich materials under in vivo conditions in goats

This study assessed the ultrastructural changes caused in adult Haemonchus contortus obtained from goats fed fodder based on polyphenol-rich plants Lysiloma latisiliquum or Onobrychis viciifolia or from goats drenched with quebracho extract, Schinopsis spp. The H. contortus were obtained from artificially infected goats used as models to investigate the anthelmintic effect of feeding or drenching with the polyphenol-rich materials. Nematode populations were exposed to polyphenol-rich plant materials by feeding host goats for 8 consecutive days (D28 to D35 post-infection) with (a) L. latisiliquum fodder at 800 g fresh basis/day, (b) O. viciifolia fodder offered ad libitum, and (c) drenched with a solution containing quebracho extract (90 g/day). Meanwhile, control H. contortus were obtained from goats fed polyphenol-free diets. The H. contortus specimens were recovered from the goats on D36 post-infection, and transmission electron microscopy (TEM) was used to identify ultrastructural changes. In vivo exposure to different polyphenol-rich plant materials caused vacuolization of the nematodes’ intestinal, muscular and hypodermal cells. These alterations represent the first evidence of cell damage caused in H. contortus when hosts were fed or drenched with polyphenol-rich materials. Ultrastructural changes affecting several types of cells could explain modifications in worm motility and nutrition, eventually affecting H. contortus reproductive success. This study contributes to our understanding of the mechanisms of action of polyphenol-rich plants against H. contortus when given as nutraceuticals to goats.

Effects of Acacia mearnsii supplementation on nutrition, parasitological, blood parameters and methane emissions in Santa Inês sheep infected with Trichostrongylus colubriformis and Haemonchus contortus

Gastrointestinal nematodes are a main problem for ruminant production, reducing animal performance and increasing environmental impact per unit of animal product generated. Tannin supplementation may lead to positive results regarding aspects such as parasitic infections and methane (CH₄) emissions. Therefore, the objective of this experiment was to evaluate the effects of the condensed tannins (CT) extract made of powdered Acacia mearnsii bark (PAB) on nutrition, parasitic status and CH₄ emissions in sheep artificially infected with Trichostrongylus colubriformis and Haemonchus contortus. Twenty 10-month old Santa Inês lambs (24.7 ± 3.14 kg of initial body weight) were used in a 50-day trial. Animals were divided in four treatment groups according to parasitic infection and PAB supplementation: two control groups without infections, one without PAB (C-) (n = 4) and one with PAB (C+) (n = 4); two infected groups, one without PAB (I-) (n = 6) and another receiving PAB (I+) (n = 6). Initially, animals were kept in individual pens where they were fed ad libitum chopped tifton 85 hay (Cynodon spp.) and 210 g/animal/day of concentrate. On the first day of experiment, animals of I- and I+ groups were artificially infected with infective larvae (L3) of T. colubriformis and H. contortus. Lambs were weighed fortnightly to calculate average daily body weight gain (ADG). Blood and faeces samples were also collected in the same moment of weighing for the evaluation of blood parameters and faecal egg count (FEC) respectively. After 40 days of experiment, measurements of CH₄ emissions in small chamber system started and following that, apparent total tract digestibility (ATTD) assay was carried out in metabolic cages. In the end of experimental period (50 days), lambs were slaughtered and samples of abomasum and small intestine content were collected for worm count, identification, and eggs/female count. No significant (p > 0.05) treatment effects were verified for ADG, ATTD and worm count. Blood parameters were affected in both infected groups (p < 0.05) from the 28th experimental day onwards, when these animals started to show reduced red blood cells, haemoglobin and packed cell volume when compared to C- and C+. Decreased FEC was verified in I+ when compared to I- and also, H. contortus eggs/female worm for I+ was lower than for I- (p < 0.05). Both infected groups showed higher CH₄ emissions than the control groups (p < 0.05). Results highlighted the anthelmintic potential of PAB and indicated methanogenic effect of parasitic nematode infections.

Across and within breed differences in the relationship between packed cell volume and fecal egg count in growing meat goat and hair sheep males naturally and artificially infected with gastrointestinal nematodes

The relationship between packed cell volume (PCV) and fecal egg count (FEC) in different breeds of meat goats and hair sheep infected with gastrointestinal nematodes, including Haemonchus contortus, was characterized. Growing males from eight commercial and two research farms (one Kiko, Spanish, Dorper, and St. Croix; three Boer; four Katahdin) in the southcentral United States were evaluated in a central performance test with ad libitum intake of a 50% concentrate pelleted diet. There were 84 Boer, 55 Kiko, and 57 Spanish goats and 52 Dorper, 129 Katahdin, and 49 St. Croix sheep. During adaptation, animals were dewormed then dosed with 10,000 infective H. contortus larvae. PCV and FEC were determined before deworming (i.e., natural infection potentially with multiple internal parasites) and 21, 28, 35, 42, and 49 days after artificial infection. Effects of species, breed, and year were analyzed with mixed effects models including day of sampling post dosing as a repeated measure and FEC and FEC × breed as covariates. Moreover, differences in correlation coefficients between PCV and logarithmic FEC (lnFEC) among species, breed, year, and day of sampling were evaluated. Breed affected (P ≤ 0.001) PCV in goats (24.8, 27.2, and 26.0% for Boer, Kiko, and Spanish, respectively; SEM = 0.42) and sheep (29.8, 26.7, and 31.0% for Dorper, Katahdin, and St. Croix, respectively; SEM = 0.28). There were effects of FEC × breed (P ≤ 0.029) on PCV for Boer, Kiko, Dorper, Katahdin, and St. Croix (-0.31, -0.33, -0.46, -0.46, and - 0.49% per 1000 eggs, respectively) but not for Spanish goats (P = 0.451). With all data, PCV and lnFEC with natural infection were highly correlated (P < 0.001) for Boer and Kiko goats and Dorper and Katahdin sheep (r = -0.59, -0.67, -0.77, and - 0.84, respectively) but not for Spanish goats or St. Croix sheep (P ≥ 0.323). Correlation coefficients for artificial infection with H. contortus were significant (P ≤ 0.002) except for Spanish goats, although values were lower (-0.40, -0.21, -0.23, -0.47, and - 0.28 for Boer, Kiko, Dorper, Katahdin, and St. Croix, respectively) compared with natural infection. In conclusion, PCV was not related to FEC in Spanish goats infected either naturally or artificially, and the nature of the relationship varied among breeds of goats and sheep. Based on the magnitude of the FEC × breed coefficient, sheep incurred a relatively greater reduction in PCV as FEC increased, and correlation coefficients indicate stronger relationships with natural than artificial infection.

Effects of grazing birdsfoot trefoil-enriched pasture on managing Haemonchus contortus infection in Suffolk crossbred lambs

High-tannin forages can be used to help mitigate the serious limitations associated with gastrointestinal nematode (GIN) infections on efficient small ruminant production. The objective of this experiment was to determine how grazing a GIN-free, established stand of a high-tannin cultivar of birdsfoot trefoil (Lotus corniculatus L.) influenced the prevention or treatment of Haemonchus contortus (Hc) infection in lambs. A birdsfoot trefoil-enriched pasture was established on an area that was previously row cropped and not grazed for at least 15 yr. Treatments included preventative (PREV) with parasite-naïve lambs transitioned onto pasture 1 wk prior to receiving an infection of 10,000 Hc larvae, therapy (THER) with parasite-naïve lambs infected with 10,000 Hc larvae 4 wk prior to the start of grazing, and control (CONT) with naïve, uninfected lambs to verify that natural infection did not occur on pasture. Each treatment group of 12 Suffolk crossbred lambs was divided into 3 replicates per treatment, and all were supplemented with a grain mix to provide 16% CP. Fecal egg count (FEC, eggs/g wet feces) in THER lambs peaked 1 wk after the start of grazing (9,404) and after 4 wk fell to 1,068, equivalent to a FEC reduction of 88.6%. Lambs in PREV had a peak FEC of 4872 at 4 wk after infection where peak FEC was 48% less in PREV than THER lambs. Lambs in CONT did not have measurable FEC for the duration of this study. Packed cell volume (PCV, %) reflected infection status of the lambs in each group, where CONT (32%) had the highest (P < 0.05) PCV followed by THER (29%) and PREV (26%). Total weight gained in CONT lambs was greatest at 5.51 kg (P < 0.01), whereas THER and PREV (2.68 and 2.97 kg, respectively) did not differ. Grazing birdsfoot trefoil-enriched pasture can have both therapeutic and preventative effects on Hc infection in lambs and can be used in a systems approach to control GIN parasites in grazing sheep.

Anthelmintic effect and tissue alterations induced in vitro by hydrolysable tannins on the adult stage of the gastrointestinal nematode Haemonchus contortus

Haemonchus contortus constitutes a severe problem for ruminant's production, it is the most frequent nematode parasite both in template and tropical regions, induces economical losses, and shows increasing resistance to currently available anthelmintics. Tannins are secondary metabolites that naturally fulfill defense functions in plants, representing a non-conventional, natural alternative in the treatment of gastrointestinal parasites in sheep. The objective of this work was to explore the in vitro anthelmintic activity of hydrolysable tannins on adult stage of Haemonchus contortus. Adults nematodes were obtained directly from the abomasum of ovines, and a dose response curve was performed with tannins extract at 0, 2, 4, 8, 25 and 50 mg/mL, and a time response curve at 0.5, 1, 2 and 24 h at 37 °C. Hydrolysable tannins decreased motility and induced mortality of H. contortus. We observed cuticle disruption around the mouth and reproductive organs, as well as evisceration. After 24 h of exposition, 8 mg/mL induced 83% of mortality and with 25 mg/kg 100% of mortality was achieved. The LD₅₀ was 3.54 mg/mL, while LD₉₀ was 10 mg/mL. We propose hydrolysable tannins as an alternative to contribute in the nematode control in ruminants.

Factors associated with strongyle infection in goats at the individual and farm level

OBJECTIVE To identify factors associated with strongyle infection and parasite reduction strategies associated with low strongyle fecal egg counts (FECs) in goats on farms in North Carolina. DESIGN Cross-sectional study. ANIMALS 631 adult goats on 52 farms in North Carolina. PROCEDURES Participating farms were visited to collect fecal samples from goats and administer a survey regarding goat, environmental, and management factors. The McMaster technique was used to determine strongyle FEC for each sample. Univariate followed by multivariate modeling was performed to identify factors associated with FEC at the farm and individual goat level. RESULTS Multivariate analysis controlling for several other factors and multiple comparisons revealed that farms on which no anthelmintic drugs had ever been used had the lowest mean FECs, compared with farms on which specific strategies for parasite control were used; no other variables were significant. For individual goat FEC, significant variables included goat breed, breed type, owner-defined purpose, daily dietary protein intake, and fecal coccidia score. In particular, companion goats (vs meat or dairy goats) had the lowest FECs. Higher dietary protein intake and coccidia scores were associated with higher FECs. Among females, goats that had kidded in the last 6 weeks had the highest FECs. CONCLUSIONS AND CLINICAL RELEVANCE Various factors were identified that appeared to influence the likelihood of strongyle infection in goats. The finding that farms with no history of anthelmintic use had the lowest mean FECs suggested that a focus on preventative measures could reduce the need for anthelmintic drugs and, by extension, lessen the opportunity for the development of anthelmintic resistance.

Effective eradication of pinworms (Syphacia obvelata and Aspiculuris tetraptera) with Polygonum cognatum Meissn

Polygonum cognatum Meissn. (Polygonaceae) is a wild edible plant known locally as "solucanotu, madimak" in Turkey and it has been used for various purposes, such as diuretic and antidiabetic, as well to treat oxyuris and worms internally in humans. The present study was carried out to investigate the anthelmintic activity of various extracts were obtained from the aerial parts of P. cognatum in order to justify its traditional usage in Turkish folk medicine. n-Hexane, ethyl acetate and methanol extracts were prepared from the aerial parts of the plant, successively. The anthelmintic potentials of these extracts were evaluated on mice naturally infected with Syphacia obvelata and Aspiculuris tetraptera. Cellophane perianal tape test and fecal flotation test were used for the activity screening. The results were compared with control and reference groups. In addition to all these experiments, the total amount of phenolic compounds and tannin contents thought to be responsible for the activity were evaluated for all extracts. According to the results, it has been found that the methanolic extract reduced the number of S. obvelata (66.8%) and A. tetraptera (73.4%) eggs. Moreover, the methanolic extract include higher amount of total phenolic compound (48.75 ± 0.82 mg of GA/g of extract) and tannin (30.04 ± 0.22 mg TA/g of extract) than n-Hexane (17.21 ± 0.75 mg of GA/g of extract; 6.82 ± 0.41 mg TA/g of extract) and ethyl acetate (25.06 ± 0.94 mg of GA/g of extract; 10.29 ± 0.34 mg TA/g of extract); therefore the anthelmintic activity could be related to these constituents. The present study explored the anthelmintic potential of P. cognatum. Further studies should be conducted into the mechanism of these compounds' against helminths. This study can be an important step in the discovery of new anthelmintic agents.

Condensed Tannin Changes along the Digestive Tract in Lambs Fed with Sainfoin Pellets or Hazelnut Skins

The variable anthelmintic efficacy of condensed tannins (CT) against gastrointestinal nematodes may depend on CT concentration, composition, or fate along the digestive tract. We analyzed CT concentration and composition by acetone-HCl-butanol and thiolysis coupled to HPLC-MS in digesta and feces of lambs. Lambs had been infected with Haemonchus contortus and Trichostrongylus colubriformis and received sainfoin pellets and hazelnut skins of contrasting prodelphinidin/procyanidin ratios. The digesta and feces had lower CT concentrations than the original feeds but similar concentration patterns across the digestive compartments. The changes in assayable CT concentrations between rumen, abomasum, and small intestine may be due to complex formation between CT and other dietary components. However, the large CT disappearance (61-85%) from feed to feces could also indicate that CT may have been structurally modified, degraded, or absorbed during digestion. Interestingly, there were no changes in the structural features of assayable CT in the digesta.

Comparison of the in vitro anthelmintic effects of Acacia nilotica and Acacia raddiana

Gastrointestinal nematodes are a major threat to small ruminant rearing in the Sahel area, where farmers traditionally use bioactive plants to control these worms, including Acacia nilotica and Acacia raddiana. The main aim of this study was to screen the potential anthelmintic properties of aqueous and acetone extracts of leaves of these two plants based on three in vitro assays: (1) the egg hatch inhibition assay (EHA); (2) the larvae exsheathment inhibition assay (LEIA) using Haemonchus contortus as a model; and (3) an adult mortality test (AMT) applied on Caenorhabditis elegans. For the EHA, only A. raddiana was effective with IC₅₀ = 1.58 mg/mL for aqueous extract, and IC₅₀ = 0.58 mg/mL for acetonic extract. For the LEIA, all extracts inhibited the exsheathment of larvae compared to the controls, and the aqueous extract of A. nilotica was more larvicidal with IC₅₀ = 0.195 mg/mL. In general, all responses to the substances were dose-dependent and were significantly different from the control group (p < 0.05). For the AMT, the extracts of the two Acacia species were effective but A. raddiana showed greater efficacy with 100% mortality at 2.5 mg/mL and LC₅₀ = 0.84 mg/mL (acetonic extract). The addition of polyvinyl polypyrrolidone (PVPP) to the extracts suggested that tannins were responsible for blocking egg eclosion and inducing adult mortality but were not responsible for exsheathment inhibition. These results suggest that the leaves of these Acacia species possess ovicidal and larvicidal activities in vitro against H. contortus, and adulticidal effects against C. elegans.

Terminalia catappa: Chemical composition, in vitro and in vivo effects on Haemonchus contortus

Haemonchus contortus is the most important nematode in small ruminant systems, and has developed tolerance to all commercial anthelmintics in several countries. In vitro (egg hatch assay) and in vivo tests were performed with a multidrug strain of Haemonchus contortus using Terminalia catappa leaf, fruit pulp, and seed extracts (in vitro), or pulp and seed powder in lambs experimentally infected with H. contortus. Crude extracts from leaves, fruit pulp and seeds obtained with 70% acetone were lyophilized until used. In vitro, the extracts had LC₅₀=2.48μg/mL (seeds), LC₅₀=4.62μg/mL (pulp), and LC₅₀=20μg/mL (leaves). In vitro, seed and pulp extracts had LC₅₀ similar to Thiabendazole (LC₅₀=1.31μg/mL). Condensed tannins were more concentrated in pulp extract (183.92g of leucocyanidin/kg dry matter) than in either leaf (4.6g) or seed (35.13g) extracts. Phytochemical tests established that all extracts contained alkaloids, flavonoids, saponins, phenols, and terpenoids. Based on these results, in vivo tests were performed to evaluate the anthelmintic activity of T. catappa whole fruit (pulp+seed) powder. Male Santa Ines lambs were artificially infected with multidrug-resistant H. contortus and divided, according to similar fecal egg count (FEC) and weight, into two groups: Control (infected/untreated) and treated (infected/treated with whole fruit powder). Whole fruit powder was mixed with concentrate and provided at 2g/kg of body weight (BW) for five days. After treatment, parasitological analysis (FEC and egg hatch assay), renal profile (urea and creatinine), liver profile (aspartate aminotransferase) and BW were determined. In vitro (based on LC₅₀), seed/pulp extracts had ovicidal effect similar to Thiabendazole but whole fruit powder had no anthelmintic effect on adult nematodes in the abomasum. We discuss the plausible causes of the lack of in vivo activity.

Medicinal plant extracts and plant-derived polyphenols with anthelmintic activity against intestinal nematodes

Covering: 2001 up to the end of 2016Polyphenols comprise a structurally diverse class of natural products. As the development of new anthelmintic drugs against soil-transmitted helminthiases is an urgent need and polyphenols are widely used in the treatment of nematode infections in traditional medicine and modern science, we summarize the state of knowledge in the period of mainly 2001 up to the end of 2016 on plant extracts with known polyphenolic composition and of defined polyphenols, mainly from the classes of condensed and hydrolysable tannins, flavonoids, and phenylpropanoids. The diverse biological activity against different helminths and the underlying mechanisms are reviewed.

Breeding for resistance to gastrointestinal nematodes - the potential in low-input/output small ruminant production systems

The control of gastrointestinal nematodes (GIN) is mainly based on the use of drugs, grazing management, use of copper oxide wire particles and bioactive forages. Resistance to anthelmintic drugs in small ruminants is documented worldwide. Host genetic resistance to parasites, has been increasingly used as a complementary control strategy, along with the conventional intervention methods mentioned above. Genetic diversity in resistance to GIN has been well studied in experimental and commercial flocks in temperate climates and more developed economies. However, there are very few report outputs from the more extensive low-input/output smallholder systems in developing and emerging countries. Furthermore, results on quantitative trait loci (QTL) associated with nematode resistance from various studies have not always been consistent, mainly due to the different nematodes studied, different host breeds, ages, climates, natural infections versus artificial challenges, infection level at sampling periods, among others. The increasing use of genetic markers (Single Nucleotide Polymorphisms, SNPs) in GWAS or the use of whole genome sequence data and a plethora of analytic methods offer the potential to identify loci or regions associated nematode resistance. Genomic selection as a genome-wide level method overcomes the need to identify candidate genes. Benefits in genomic selection are now being realised in dairy cattle and sheep under commercial settings in the more advanced countries. However, despite the commercial benefits of using these tools, there are practical problems associated with incorporating the use of marker-assisted selection or genomic selection in low-input/output smallholder farming systems breeding schemes. Unlike anthelmintic resistance, there is no empirical evidence suggesting that nematodes will evolve rapidly in response to resistant hosts. The strategy of nematode control has evolved to a more practical manipulation of host-parasite equilibrium in grazing systems by implementation of various strategies, in which improvement of genetic resistance of small ruminant should be included. Therefore, selection for resistant hosts can be considered as one of the sustainable control strategy, although it will be most effective when used to complement other control strategies such as grazing management and improving efficiency of anthelmintics currently.

Interactions Between Nutrition and Infections With Haemonchus contortus and Related Gastrointestinal Nematodes in Small Ruminants

Interactions between host nutrition and feeding behaviour are central to understanding the pathophysiological consequences of infections of the digestive tract with parasitic nematodes. The manipulation of host nutrition provides useful options to control gastrointestinal nematodes as a component of an integrated strategy. Focussed mainly on the Haemonchus contortus infection model in small ruminants, this chapter (1) illustrates the relationship between quantitative (macro- and micro-nutrients) and qualitative (plant secondary metabolites) aspects of host nutrition and nematode infection, and (2) shows how basic studies aimed at addressing some generic questions can help to provide solutions, despite the considerable diversity of epidemiological situations and breeding systems.

Diagnosis, Treatment and Management of Haemonchus contortus in Small Ruminants

Haemonchus contortus is a highly pathogenic, blood-feeding nematode of small ruminants, and a significant cause of mortalities worldwide. Haemonchosis is a particularly significant threat in tropical, subtropical and warm temperate regions, where warm and moist conditions favour the free-living stages, but periodic outbreaks occur more widely during periods of transient environmental favourability. The clinical diagnosis of haemonchosis is based mostly on the detection of anaemia in association with a characteristic epidemiological picture, and confirmed at postmortem by the finding of large numbers of H. contortus in the abomasum. The detection of impending haemonchosis relies chiefly on periodic monitoring for anaemia, including through the 'FAMACHA' conjunctival-colour index, or through faecal worm egg counts and other laboratory procedures. A range of anthelmintics for use against H. contortus is available, but in most endemic situations anthelmintic resistance significantly limits the available treatment options. Effective preventative programmes vary depending on environments and enterprise types, and according to the scale of the haemonchosis risk and the local epidemiology of infections, but should aim to prevent disease outbreaks while maintaining anthelmintic efficacy. Appropriate strategies include animal management programmes to avoid excessive H. contortus challenge, genetic and nutritional approaches to enhance resistance and resilience to infection, and the monitoring of H. contortus infection on an individual animal or flock basis. Specific strategies to manage anthelmintic resistance centre on the appropriate use of effective anthelmintics, and refugia-based treatment schedules. Alternative approaches, such as biological control, may also prove useful, and vaccination against H. contortus appears to have significant potential in control programmes.

Dried, ground banana plant leaves (Musa spp.) for the control of Haemonchus contortus and Trichostrongylus colubriformis infections in sheep

To evaluate the anthelmintic effect of Musa spp. leaves, 12 animals were artificially infected with Haemonchus contortus, and another 12 animals were infected with Trichostrongylus colubriformis. Then, both treatment groups were offered 400 g of dried ground banana plant leaves, and the control animals were offered only 1000 g of coast cross hay. During the trials, the animals received weekly physical examinations. The methods used to evaluate the efficiency of this treatment were packed cell volume, total plasma protein and faecal egg counts, and egg hatchability tests were performed on days -2, +3, +6, +9, +13 and +15. Coproculture tests were performed on day -2 to confirm monospecific infections. In the FEC and EHT, a statistically significant difference (0.04, 0.005; p < 0.05) was noted for T. colubriformis. There were no statistically significant differences (p > 0.05) for Haemochus contortus group in all tests. Our results confirmed previous findings suggesting that dried ground banana plant leaves possess anthelmintic activity.

Schistosomicidal, hepatoprotective and antioxidant activities of the methanolic fraction from Clerodendrum umbellatum Poir leaves aqueous extract in Schistosoma mansoni infection in mice

BACKGROUND

The intensive use of Praziquantel for the treatment of schistosomiasis has raised concerns about the possible emergence of drug-resistant schistosomes. As drug treatment is an important feature of schistosome control programs, the search for alternative drugs is therefore a priority. The aim of this study was to assess the schistosomicidal, hepatoprotective and antioxidant activities of the methanolic fraction from Clerodendrum umbellatum Poir leaves aqueous extract.

METHODS

A phytochemical screening of the fraction of C. umbellatum was conducted. The fraction was administered orally and daily to Schistosoma mansoni-infected mice (BALB/c) from the 36th day post-infection for 28 days at 100, 200 and 400 mg/kg. Praziquantel (500 mg/kg) was used as reference drug. Non-infected and infected-untreated mice served as controls. All mice were sacrificed at 65th day post-infection. Body weight, liver/body and spleen/body weights, as well as worm burden, fecal egg count, liver and intestine egg load were determined. In the plasma, levels of total protein, transaminases (ALT, AST), alkaline phosphatase and total bilirubin were monitored to assess the possibility of liver damage. Malondialdehyde (MDA), catalase (CAT) and glutathione (GSH) levels were measured in the liver as biomarkers of the oxidative stress.

RESULTS

The phytochemical analysis of the fraction from C. umbellatum aqueous leaves extract revealed the presence of alkaloids, flavonoids, cardiac glycosides, phenols, saponins, tannins and terpenoids. The worm burden, fecal egg count and egg load in the liver and intestine of infected mice treated with the fraction were significantly (p < 0.001) fewer than in infected-untreated mice. Only the highest-fraction dose reduced the worm and egg burdens in a similar way as praziquantel. Hepatosplenomegaly induced by S. mansoni infection was reduced by the treatment. The liver function on infected mice was ameliorate after administration of the fraction by significant reduction of ALT activity (35.43 to 45.25%) and increase of total protein level (44.79 to 70.03%). The methanolic fraction of C. umbellatum prevents the elevated MDA level induced by the infection while significant increase in catalase activity (297.09 to 438.98%) and glutathione level (58.23 to 95.88%) were observed after treatment.

CONCLUSIONS

This study disclosed the schistosomicidal, hepatoprotective and antioxidant activities of the methanolic fraction from C. umbellatum leaves aqueous. These fraction's activities were similar to those of praziquantel. This fraction can be considered as a promising source for schistosomicidal agents.

The effect of vitamin E supplementation on an experimental Haemonchus contortus infection in lambs

The objective of this study was to investigate the effect of vitamin E supplementation on an experimental Haemonchus contortus infection in lambs. Twenty lambs were stratified into two treatment groups based on fecal egg count. Worm-free lambs, 28-32 weeks of age, were supplemented with vitamin E (d-α-tocopherol) for 12 weeks following the recommendations of the National Research Council for the minimum daily requirement (control; 5.3 IU/kg body weight (BW)/day (d), n=10) or the requirement for optimal immune function (VE10; 10 IU/kg BW/d, n=10). Five weeks following initiation of vitamin E supplementation, lambs were infected with 10,000 H. contortus third stage larvae. Samples were taken weekly to quantify serum α-tocopherol, serum total non-specific immunoglobulin (Ig)G, whole worm antigen specific IgG, packed cell volume (PCV), and fecal egg count (FEC). Expression of cytokine genes IFN-λ and IL-4 were measured in peripheral blood collected prior to slaughter. Lambs were necropsied six weeks after infection and the α-tocopherol concentration of liver, muscle and lymph node were measured as well as abomasal worm burden and histologic evaluation of the abomasum for inflammation and enumeration of eosinophils and globule leukocytes. The livers of VE10 lambs contained slightly more α-tocopherol than control lambs. No differences were observed in serum, muscle or lymph node α-tocopherol concentration, serum IgG or peripheral mRNA expression of IL-4 or IFN-λ between control and VE10 lambs. However, lambs supplemented at 10IU/kg BW/d had a lower PCV reduction, FEC and worm burden 49% less than control lambs. Worm burden was negatively correlated with eosinophil (-0.720, P<0.05) and globule leukocyte count (-0.867, P<0.05). Strong positive correlations were observed within the inflammatory cell response in VE10 lambs that was absent in control lambs. These data indicate that additional vitamin E supplementation resulted in lower worm burden and greater recruitment of innate effector cells to the site of infection. Further studies are necessary to elucidate the mechanism by which vitamin E affects greater recruitment of innate effector cells to the abomasum during gastrointestinal nematode infection of lambs.

Effects of supplementation with dietary green tea polyphenols on parasite resistance and acute phase protein response to Haemonchus contortus infection in lambs

The objective of this study was to determine the effects of supplementation with dietary green tea polyphenols (GTPs) on parasite resistance and acute phase protein (APP) response to Haemonchus contortus infection in lambs. Thirty male Ujumqin lambs were randomly assigned to five treatment groups for an 8-week feeding period. Treatments included: (1) uninfected as control, (2) infected but not given GTP (INFGTP0) and (3)-(5) infected and fed 2, 4, or 6g GTP/kg feed (dry matter basis; INFGTP2, INFGTP4, and INFGTP6, respectively). Fecal and blood samples were collected to determine fecal egg count (FEC), packed cell volume (PCV), and APP concentrations. Live weight was measured once every 2 weeks. At the end of the feeding period, lambs were slaughtered to determine the adult H. contortus burden. The results demonstrated interaction effects between treatment and sampling time on the average daily gain (ADG; P=0.0005), FEC (P<0.0001), PCV (P=0.0005), and concentrations of serum amyloid A (SAA), haptoglobin (Hp), lipopolysaccharide binding protein (LBP), and α1-acid glycoprotein (α1AGP) (P<0.0001). From days 0 to 56, the ADG values for all infected lambs were lower than that of uninfected lambs, but the ADG values for all GTP-fed lambs were higher than that of INFGTP0 lambs, especially from days 28 to 42. The FECs of all GTP-fed lambs were higher than those of uninfected lambs but lower than that of INFGTP0 lambs. The PCVs of all infected lambs were lower than those of uninfected lambs, but PCV increased with increasing amounts of GTP supplementation. Furthermore, supplementation with different concentrations of GTP significantly reduced the numbers of adult H. contortus, including both males and females (P<0.0001), and the H. contortus burden in INFGTP6 lambs was reduced to uninfected levels. Overall, the SAA, Hp, LBP, and α1AGP concentrations of all infected lambs were higher than those of uninfected lambs from days 0 to 56. Two peaks in expression were observed from days 0 to 3 and at day 28, and APP concentrations of all GTP-fed lambs were lower than those of INFGTP0 lambs, except for SAA in INFGTP6 lambs. In conclusion, quantitative measurements of APP responses to H. contortus infection provide valuable diagnostic information for monitoring infection progression and treatment responses in lambs. An appropriate dose of dietary GTP supplementation can increase host resistance by reducing H. contortus burden and weight loss and suppressing blood APP expression.

Studies on Emblica officinalis derived tannins for their immunostimulatory and protective activities against coccidiosis in industrial broiler chickens

The present study reports the effect of Emblica officinalis (EO) derived tannins on humoral immune responses and their protective efficacy against Eimeria infection in chickens. Tannins were extracted from EO and characterized by HPLC. EO derived tannins (EOT) and commercial tannins (CT) were orally administered in broiler chicks in graded doses for three consecutive days, that is, 5th-7th days of age. On day 14 after administration of tannins, humoral immune response was detected against sheep red blood cells (SRBCs) by haemagglutination assay. Protective efficacy of tannins was measured against coccidial infection, induced by Eimeria species. Results revealed higher geomean titers against SRBCs in chickens administered with EOT as compared to those administered with CT and control group. Mean oocysts per gram of droppings were significantly lower (P < 0.05) in EOT administered chickens as compared to control group. Lesion scoring also showed the lowest caecal and intestinal lesion score of mild to moderate intensity in chickens administered with EOT. Further, significantly higher (P < 0.05) daily body weight gains and antibody titers were detected in EOT administered chickens as compared to those of CT administered and control groups. EOT showed the immunostimulatory properties in broilers and their administration in chickens boost the protective immunity against coccidiosis.

Influence of Dietary Supplementation of Condensed Tannins through Leaf Meal Mixture on Intake, Nutrient Utilization and Performance of Haemonchus contortus Infected Sheep

The study assessed the effect of dietary supplementation of leaf meal mixture (LMM) containing condensed tannins (CT) on feed intake, nutrient utilization and performance of sheep infected with Haemonchus contortus. Eighteen adult sheep of similar age and body weight (25.03±1.52) were included in this study and out of these, 12 sheep were infected with single dose of infective third stage larvae of H. contortus at 2,000 larvae per sheep. The experimental sheep were allocated in three different groups' i.e. negative control (NC; no infection), control (C; H. contortus infected) and treatment (T; H. contortus infected+CT at 1.5% of the DM through LMM) and the experiment was conducted for a period of 90 d. The intake of dry matter (DM), organic matter (OM) and digestibility of DM, OM, neutral detergent fibre (NDF) and acid detergent fibre (ADF) were comparable among three animal groups. However, digestibility of crude protein (CP) and ether extract (EE) were significantly (p<0.05) higher in NC group as compared to both C and T groups. Nitrogen (N) retention (g/d or % of N intake) was significantly (p = 0.038) lower in C group as compared to T and NC groups. Daily intake (g/kg W(0.75)) of digestible crude protein (DCP), digestible organic matter (DOM) and total digestible nutrient (TDN) did not differ significantly (p<0.05) in the three groups. Haemoglobin (Hb) and packed cell volume (PCV) were significantly (p<0.001) higher in treatment group as compared to control. The level of Hb and PCV reduced (p<0.001) after 30 days of experimental feeding. CT significantly (p<0.001) reduced serum urea in T group as compared to NC and C groups. Serum proteins differed significantly (p<0.01) among the three groups. The activity of serum enzymes AST, ALT, ALP and LDH were also statistically non significant (p<0.05) among treatments. The weight of abomasal lymph nodes (ALN) in T group was higher (p<0.05) than in C group. Treatment group had lower (p<0.05) total worms and fecal egg count compared to control group. It may be concluded that dietary supplementation of CT through LMM significantly improved the N retention, and inhibited the different developmental stages of Haemonchus contortus in experimental sheep.

Scanning electron microscopy of Haemonchus contortus exposed to tannin-rich plants under in vivo and in vitro conditions

The structural changes induced in adult Haemonchus contortus after in vitro and in vivo contact with a tannin-rich (TR) plant, either tzalam (Lysiloma latisiliquum) or sainfoin (Onobrychis viciifolia), were assessed using scanning electron microscopy (SEM). All the worms used in the study were adult females. The Haemonchus adult worms were obtained from the abomasum of infected donor goats. Adult H. contortus were kept in contact with the extracts of TR plants for 24h for the in vitro assays and were compared to worms maintained in PBS (control). For the in vivo studies, the adult H. contortus parasites were obtained from artificially infected goats. All the goats were fed a tannin-free diet until D27 post-infection when infection was patent. On D28 some goats were fed fodder of one of the TR plants for seven consecutive days. Thus, their H. contortus were in contact with TR fodder within the gastrointestinal tract. The control worms were obtained from goats fed only a tannin-free diet. In the in vitro assays and in vivo studies, the SEM observations revealed structural alterations in the worms after contact with TR plants when compared to the control worms (i.e.: longitudinal and transversal folds and thicker cuticular ridges, material aggregates around the buccal capsule and/or vulva or anus). The main changes concerned the cuticle and the buccal area. The structural changes found in the worms exposed to TR plants might affect their motility and nutrition with possible consequences on their reproduction, as suggested by previous in vivo trials.