Gastrointestinal Nematodes In Ruminants Research Articles

Analysis of Protection and Immune Response against Teladorsagia circumcincta in Goats Immunised with Thiol-Binding Proteins from Adult Worms.

In view of the increasing occurrence of anthelmintic-resistant strains of gastrointestinal nematodes in ruminants, various alternative control strategies have been investigated, such as those based on the induction of protective immune responses by immunisation with parasite antigens. In this study, the protective activity of somatic antigens from adult worms of Teladorsagia circumcincta purified by affinity chromatography on thiol-sepharose was analysed in goats. After challenge, the enriched products induced a slight reduction in the cumulative faecal egg counts (21%) and in the number of worms (23.3%), with a greater effect on female worms, which also showed a reduction in parameters related to their fertility. These parasitological findings were associated with a Th2 immune response, with a prominent local humoral response and an eosinophilic infiltrate in the gastric mucosa (negatively associated with the fertility of female worms and the number of worms, respectively), as well as an infiltration of MCHII+, CD4+, IgG+ and IgA+ cells. However, several analyses showed an increase in CD8+ cells in the mucosa, as well as IL-2 expression in the gastric lymph nodes, which may have been associated with inhibition of protective responses or with the development of mixed Th1/Th2 responses, a finding that should be analysed in future studies.

Phytochemical analysis and anthelmintic activity of Combretum mucronatum leaf extract against infective larvae of soil-transmitted helminths including ruminant gastrointestinal nematodes

BackgroundSoil-transmitted helminths (STH) infect more than a quarter of the world’s human population. In the absence of vaccines for most animal and human gastrointestinal nematodes (GIN), treatment of infections primarily relies on anthelmintic drugs, while resistance is a growing threat. Therefore, there is a need to find alternatives to current anthelmintic drugs, especially those with novel modes of action. The present work aimed to study the composition and anthelmintic activity of Combretum mucronatum leaf extract (CMLE) by phytochemical analysis and larval migration inhibition assays, respectively.MethodsCombretum mucronatum leaves were defatted with petroleum ether and the residue was extracted by ethanol/water (1/1) followed by freeze-drying. The proanthocyanidins and flavonoids were characterized by thin layer chromatography (TLC) and ultra-high performance liquid chromatography (UPLC). To evaluate the inhibitory activity of this extract, larval migration assays with STH and GIN were performed. For this purpose, infective larvae of the helminths were, if necessary, exsheathed (Ancylostoma caninum, GIN) and incubated with different concentrations of CMLE.ResultsCMLE was found to be rich in flavonoids and proanthocyanidins; catechin and epicatechin were therefore quantified for standardization of the extract. Data indicate that CMLE had a significant effect on larval migration. The effect was dose-dependent and higher concentrations (1000 µg/mL) exerted significantly higher larvicidal effect (P < 0.001) compared with the negative control (1% dimethyl sulfoxide, DMSO) and lower concentrations (≤ 100 µg/ml). Infective larvae of Ascaris suum [half-maximal inhibitory concentration (IC50) = 5.5 µg/mL], Trichuris suis (IC50 = 7.4 µg/mL), and A. caninum (IC50 = 18.9 µg/mL) were more sensitive to CMLE than that of Toxocara canis (IC50 = 310.0 µg/mL), while infective larvae of Toxocara cati were largely unaffected (IC50 > 1000 µg/mL). Likewise, CMLE was active against most infective larvae of soil-transmitted ruminant GIN, except for Cooperia punctata. Trichostrongylus colubriformis was most sensitive to CMLE (IC50 = 2.1 µg/mL) followed by Cooperia oncophora (IC50 = 27.6 µg/mL), Ostertagia ostertagi (IC50 = 48.5 µg/mL), Trichostrongylus axei (IC50 = 54.7 µg/mL), Haemonchus contortus (IC50 = 145.6 µg/mL), and Cooperia curticei (IC50 = 156.6 µg/mL).ConclusionsThese results indicate that CMLE exhibits promising anthelmintic properties against infective larvae of a large variety of soil-transmitted nematodes.Graphical

The identification of small molecule inhibitors with anthelmintic activities that target conserved proteins among ruminant gastrointestinal nematodes.

Gastrointestinal nematode (GIN) infections are a major concern for the ruminant industry worldwide and result in significant production losses. Naturally occurring polyparasitism and increasing drug resistance that potentiate disease outcomes are observed among the most prevalent GINs of veterinary importance. Within the five major taxonomic clades, clade Va represents a group of GINs that predominantly affect the abomasum or small intestine of ruminants. However, the development of effective broad-spectrum anthelmintics against ruminant clade Va GINs has been challenged by a lack of comprehensive druggable genome resources. Here, we first assembled draft genomes for three clade Va species (Cooperia oncophora, Trichostrongylus colubriformis, and Ostertagia ostertagi) and compared them with closely related ruminant GINs. Genome-wide phylogenetic reconstruction showed a relationship among ruminant GINs structured by taxonomic classification. Orthogroup (OG) inference and functional enrichment analyses identified 220 clade Va-specific and Va-conserved OGs, enriched for functions related to cell cycle and cellular senescence. Further transcriptomic analysis identified 61 taxonomically and functionally conserved clade Va OGs that may function as drug targets for new broad-spectrum anthelmintics. Chemogenomic screening identified 11 compounds targeting homologs of these OGs, thus having potential anthelmintic activity. In in vitro phenotypic assays, three kinase inhibitors (digitoxigenin, K-252a, and staurosporine) exhibited broad-spectrum anthelmintic activities against clade Va GINs by obstructing the motility of exsheathed L3 (xL3) or molting of xL3 to L4. These results demonstrate valuable applications of the new ruminant GIN genomes in gaining better insights into their life cycles and offer a contemporary approach to discovering the next generation of anthelmintics.IMPORTANCEGastrointestinal nematode (GIN) infections in ruminants are caused by parasites that inhibit normal function in the digestive tract of cattle, sheep, and goats, thereby causing morbidity and mortality. Coinfection and increasing drug resistance to current therapeutic agents will continue to worsen disease outcomes and impose significant production losses on domestic livestock producers worldwide. In combination with ongoing therapeutic efforts, advancing the discovery of new drugs with novel modes of action is critical for better controlling GIN infections. The significance of this study is in assembling and characterizing new GIN genomes of Cooperia oncophora, Ostertagia ostertagi, and Trichostrongylus colubriformis for facilitating a multi-omics approach to identify novel, biologically conserved drug targets for five major GINs of veterinary importance. With this information, we were then able to demonstrate the potential of commercially available compounds as new anthelmintics.

Red Wine Inspired Chemistry: Hemisynthesis of Procyanidin Analogs and Determination of Their Protein Precipitation Capacity, Octanol-Water Partition, and Stability in Phosphate-Buffered Saline.

Ten dimeric procyanidin (PC) analogs were hemisynthesized from catechin or epicatechin and from five different aldehydes using the same mechanism that produces the important acetaldehyde-mediated adducts of proanthocyanidins (PAs) and anthocyanins in red wine. Protein precipitation capacity (PPC), octanol-water partition coefficient (log P) and stability of the PC analogs were determined. The emphasis was on the PPC because it has been shown to correlate with anthelmintic activity against gastrointestinal nematodes in ruminants and with other beneficial bioactivities in animals, as well. The PPC of PC analogs was greatly improved compared to natural PC dimers, but the capacity was not as great as that of a PC trimer or epigallocatechin gallate. The log P of PC analogs varied from hydrophobic to hydrophilic depending on the intramolecular linkage. Great variation was observed in stabilities of PC analogs in phosphate buffered saline, and the mixtures of degradation products were characterized using high-resolution mass spectrometry.

Effect of aqueous extract of Azadirachta indica leaves on gastrointestinal nematodes in ruminants: an in vitro study

High rates of gastrointestinal parasite infestation lead to the frequent use of anthelmintics for their control, resulting in resistance in the main species of gastrointestinal nematodes. Natural plant extracts, particularly those from Azadirachta indica A. Juss leaves, have been described as having antiparasitic, antimicrobial, insecticidal, antioxidant, and anticorrosive activities, which are related to the diversity of their chemical composition. This research aimed to evaluate the effect of the aqueous extract of A. indica leaves on the control of gastrointestinal nematodes in ruminants. To achieve this, an in vitro test was performed using the larval development assay, with fecal samples obtained from Pelibuey sheep, Criolla goats in the development category, and Criolla calf cattle for the culture of gastrointestinal nematode larvae. Three concentrations (minimum, medium, and maximum) were evaluated for each animal species against Haemonchus placei and Cooperia sp larvae for cattle and Haemonchus contortus, Trichostrongylus sp, and Trichuris for sheep and goats. The survival percentage indicator was evaluated at 0, 24, 48, and 72 h. The research concluded that the minimum concentration was valid for sheep and goats but not for cattle, and the medium and maximum concentrations were effective against all three animal species, resulting in 100% larval mortality. Keywords: Azadirachta, drug effects, Ruminants, Trichostrongyloidea

First report of Metarhizium anisopliae s.l. action on gastrointestinal ruminant nematodes in the free-living stage and its persistence in soil

ABSTRACT The fungus Metarhizium anisopliae is one of the most studied biological control agents in parasite control programs, especially when aiming the control of arthropods. Yet, studies using this biological agent to control gastrointestinal nematodes in ruminants are scarce. The present study evaluated the efficacy of the entomopathogenic fungus Metarhizium anisopliae sensu lato (s.l.) formulated in water and mineral oil on the free-living stages of gastrointestinal nematodes (GINs) in goats, by means of in vitro tests and in semi-natural conditions. The study also evaluated the persistence of the fungus in the soil. The experiments were constituted of four groups: control water; control oil; aqueous formulation of M. anisopliae s.l.; oil formulation of M. anisopliae s.l., each group consisting of 10 pots with Urochloa brizantha cv. MG5 grass. In the in vitro test, the groups treated with the aqueous and mineral oil formulation showed efficacy in controlling gastrointestinal nematodes of goats, providing a reduction of 45.5% and 43%, respectively, and a reduction varying from 36% to 77.9% and 42.6% to 90.2%, respectively, in the experiment under semi-natural conditions. Isolate M. anisopliae s.l. proved to be effective against goat’s gastrointestinal nematodes in the free-living stage, in both in vitro and semi-natural conditions tests, by significantly reducing the number of larvae with the formulations tested and remaining active for a period up to 52 days in the pots’soil. This study suggests the potential use of M. anisopliae s.l. for the biological control of gastrointestinal nematodes in ruminants.

Five past twelve - the resistance situation in small ruminant gastrointestinal nematodes in Germany

Anthelmintic resistance has reached alarming levels worldwide and already seriously threatens pasture-based small ruminant production in certain geographic regions. The situation in Europe has also dramatically deteriorated in the last decade. This review provides an overview of the occurrence of anthelmintic resistance in small ruminants with a particular focus on Germany and its neighbouring countries. It also covers mechanisms leading to the development and spread of anthelmintic resistance, and recommendations for a responsible use of anthelmintics in veterinary practice.

Common Plant Bioactive Components Adopted in Combating Gastrointestinal Nematodes in Small Ruminant – A Review

The high cost incurred by rural farmers on chemical anthelmintics, the reduction of the efficacy of this class of drugs and the development of resistant strains of Helminth has necessitate the search for suitable alternatives. However, there are still research gaps in the use plant secondary metabolites with no proper documentation of the active compound(s), standard administration route, mode of action, and standardization of its use in small ruminant animals. This review focuses on the use of bioactive components of plants and plant extracts in combating gastrointestinal nematodes (GIN) in ruminant animals. It highlights the importance of the use of plants in both ruminant nutrition and health, the flaws of conventional methods of treatment and the need for suitable alternatives. It further documents the major bioactive components of plants used in the treatment of GIN in ruminants and their mode of action on nematodes’ eggs, larva and adult worms. It is very clear that there exists a gap in research to validate the in vitro testing of some useful compounds in vivo owing to the identification of active components as most of them work in synergism with others, the dosing of the extracts is not uniform as the molecular weight of the selected compounds differs in most cases. Hence, this informs the need for collaborative research to validate the use of bioactive compounds and subsequent drug development to replace costly conventional anthelmintic that are constantly losing efficacy.

Do natural catastrophic events and exceptional climatic conditions also affect parasites?

Parasites and parasitologists have always lived together in good and bad luck in a sort of forced marriage. In recent times bad luck certainly prevailed, because of increasing man-made emergencies such as wars, chemical disasters, but also because of natural disasters, amplified by climate change, that condition more and more parasite–host equilibrium. The symposium at the National Congress of the Italian Society for Parasitology, was a first occasion for Italian parasitologists to reason about ‘disaster parasitology’ and researchers’ responsibilities. Extreme weather events and their impacts on parasites’ epidemiology are illustrated, comparing disasters that recently occurred in Italy with literature data. In particular, the Sardinian Island was hit subsequently by fires and floods exacerbating the effects on ecosystems and parasite–host-relationships. Examples of Cryptosporidium outbreaks in man and Fasciola hepatica infections in various hosts after heavy rains are reviewed and effects of droughts on pasture borne parasites, such as gastro-intestinal nematodes of ruminants are discussed. Heavy rains may also cause dissemination of toxic substances released accidentally from chemical plants as happened e.g. in Milan province (IT) after the dioxin hazard. The overlapping effects of strictly man-made disasters with climate change dependent extreme weather events is further challenging the understanding of what are the consequences of disasters on ecosystems and parasite epidemiology.GIS applications combined with AI programs may help to face the complex challenges, allowing the collection and analysis of spatial/temporal data at whatever level desired. Examples illustrated in the article suggest their employment also in a more systematic, prevention-oriented manner.

In vitro effect of burned pasture soil on eggs and free-living larvae of ruminant gastrointestinal nematodes

Gastrointestinal nematodes are the most expensive agent of disease currently facing the livestock production industry. Spending the beginning of their life cycle as eggs and free-living larvae, nematodes are vulnerable to a multitude of external environmental factors. Fire is a naturally occurring force of nature that has both destructive and reconstructive effects on soil characteristics which nematode stages rely on for survival. The aim of this project was to evaluate in vitro the effect of burned pasture soil (200 °C and 500 °C) on the free-living stages of ruminant nematodes. We tested the effect of burned soil on the ability of eggs to hatch and produce infective larvae, and then tested survival of infective larvae within burned soil. Adding burned soil (500 °C) to larval cultures improved larval yield compared to larval cultures containing raw soil or soil burned at a lower heat (200 °C), and raw soil improved longer term survival of infective larvae. We were able to recover significantly more larvae from samples with low soil content either as raw or soil burned at 200 °C, when compared with samples with soil burned at 500 °C. This study has shown that the survival of gastrointestinal nematodes at the L3 stage is negatively impacted by the addition of soil burned at 500 °C. Although this temperature is closest to that of a medium intensity wildfire, which is a typically destructive process in agriculture, it reduces the number of infective GIN larvae available for animals to ingest. These experiments enable us to address in vitro if post-fire soil conditions alter the number of infective larvae available on pasture, and thus the infectivity of the pasture to livestock.

Nematode predatory ability of the fungus Duddingtonia flagrans affected by in vitro sequential exposure to ovine gastrointestinal tract

Duddingtonia flagrans is a nematophagous fungus employed as a biocontrol agent of gastrointestinal nematodes in ruminants. After oral ingestion and passage through the digestive tract of animals, this microorganism captures the nematodes in the feces. The drastic conditions of ruminant digestive tract could affect fungi chlamydospores and therefore biocontrol activity. The aim of this study was to evaluate in vitro the effect of four ruminant digestive segments on the concentration and nematode predatory ability of a Colombian native strain of D. flagrans. The sequential four-step methodology proposed evaluated conditions of the oral cavity, rumen, abomasum, and small intestine such as pH (2, 6, 8), enzymes (pepsin, pancreatin), temperature (39 °C), and anaerobiosis comparing short (7 h) and long (51 h) exposure times. The results showed that the nematode predatory ability of the fungi is affected by sequential exposure to gastrointestinal segments and this effect depends on the exposure time to those conditions. After short exposure (7 h) through the four ruminant digestive segments, the fungi had a nematode predatory ability of 62%, in contrast, after long exposure (51 h) the nematode predatory ability was lost (0%). Moreover, the number of broken chlamydospores was higher in the long-exposure assay.

Copper chloride and copper sulphate in combination with nitroxynil against gastrointestinal nematodes of ruminants: A possible hitchhiking synergic effect at low concentrations

Infections caused by Haemonchus spp. and Trichostrongylus spp. are major health problems for sheep and cattle. The objective of this study was to determine the efficacy of copper chloride (CuCl2), and copper sulphate (CuSO4) at 2.0, 7.0, 30.0, 125.0, 500.0, and 2000.0 µM formulations, and nitroxynil 34% (NTX) at 0.235 mM against gastrointestinal nematodes (GINs) of ruminants. Hence, the in vitro egg hatch test (EHT), the larval development test (LDT), and the larval migration inhibition test (LMIT) were used. Haemonchus spp. (52%) and Trichostrongylus spp. (38%) were the most frequently found parasites. The data fitted a concentration-dependent shape with the highest efficacies of CuCl2 and CuSO4 at 95.2 and 97.3% for parasites collected from sheep, and 95.8 and 93.4% from cattle, respectively. The combination of the 50% inhibitory concentration (IC50) of CuCl2 and CuSO4 and the IC10 of NTX showed up to a 52% increase in efficacy above the expected additive results, demonstrating a synergic/drug enhancer interaction. NTX may retain Cu-II ions by complexation, in a hitchhiking mechanism carrying the salts across the parasite cell wall, causing oxidative stress as a consequence of free radical production and cell damage. Synergy data between NTX and CuCl2, and CuSO4 represent a viable opportunity to develop new formulations for combating parasites of ruminants (i.e., Fasciola hepatica, Haemonchus spp., and Oesophagostomum spp.).

Potential of Anthelmintic Herbal Drugs against Gastrointestinal Nematodes in Farm Animals: A Review

Gastrointestinal (GI) nematode infections are one of the most prevalent and significant problems in livestock worldwide. This study aimed to review the potential of anthelmintic herbal drugs against gastrointestinal nematodes in farm animals. Anthelmintic drugs are the most common method of controlling GI nematodes since they are simple, cheap, and provide therapeutic and prophylactic protection. However, the problem has become complicated due to the emergence of resistance to anthelmintic drugs because anthelmintic drugs are used indiscriminately to treat parasitic diseases. Anthelmintic resistance in GI nematodes of ruminants is a global problem. Many domestic animals possess multi-class resistance to all classes of anthelmintics. Synthetic anthelmintics could be unsafe as they can cause side effects and toxicity. Therefore, plants are used to develop and discover novel substances acting as anthelmintics. Herbal drugs have become increasingly popular because of their fewer side effects in recent years. Consequently, the demand for herbal formulations of anthelmintic drugs is increasing. The development of instrumental analysis accelerates the preparation of phytochemical constituents and their standardization, and this field is becoming critical for research.

Regional heterogeneity and unexpectedly high abundance of Cooperia punctata in beef cattle at a northern latitude revealed by ITS-2 rDNA nemabiome metabarcoding

BackgroundThe species composition of cattle gastrointestinal nematode (GIN) communities can vary greatly between regions. Despite this, there is remarkably little large-scale surveillance data for cattle GIN species which is due, at least in part, to a lack of scalable diagnostic tools. This lack of regional GIN species-level data represents a major knowledge gap for evidence-based parasite management and assessing the status and impact of factors such as climate change and anthelmintic drug resistance.MethodsThis paper presents a large-scale survey of GIN in beef herds across western Canada using ITS-2 rDNA nemabiome metabarcoding. Individual fecal samples were collected from 6 to 20 randomly selected heifers (n = 1665) from each of 85 herds between September 2016 and February 2017 and 10–25 first season calves (n = 824) from each of 42 herds between November 2016 and February 2017.ResultsGastrointestinal nematode communities in heifers and calves were similar in Alberta and Saskatchewan, with Ostertagia ostertagi and Cooperia oncophora being the predominant GIN species in all herds consistent with previous studies. However, in Manitoba, Cooperia punctata was the predominant species overall and the most abundant GIN species in calves from 4/8 beef herds.ConclusionsThis study revealed a marked regional heterogeneity of GIN species in grazing beef herds in western Canada. The predominance of C. punctata in Manitoba is unexpected, as although this parasite is often the predominant cattle GIN species in more southerly latitudes, it is generally only a minor component of cattle GIN communities in northern temperate regions. We hypothesize that the unexpected predominance of C. punctata at such a northerly latitude represents a range expansion, likely associated with changes in climate, anthelmintic use, management, and/or animal movement. Whatever the cause, these results are of practical concern since C. punctata is more pathogenic than C. oncophora, the Cooperia species that typically predominates in cooler temperate regions. Finally, this study illustrates the value of ITS-2 rDNA nemabiome metabarcoding as a surveillance tool for ruminant GIN parasites.Graphical

Benzimidazole resistant Haemonchus contortus in a wildlife park.

Anthelmintic resistance (AR) of ruminant gastrointestinal nematodes (GINs) constitutes a major problem worldwide. Among GINs, the abomasal blood-feeding parasite Haemonchus contortus is particularly pathogenic and may show resistance against all major anthelmintic substance classes. In the present study, the death of a 1,5 year-old European bison (Bison bonasus) from a German wildlife park due to haemonchosis despite frequent anthelmintic treatment of the herd with fenbendazole as well as doramectin prompted an investigation regarding AR. Pooled faecal samples were collected from four different bison groups as well as from mouflons (Ovis orientalis), elk (Alces alces), reindeer (Rangifer tarandus), sika deer (Cervus nippon), Persian fallow deer (Dama mesopotamica) and red deer (Cervus elaphus) housed by the wildlife park. After coproscopical examination, faecal larval cultures were established. Haemonchus contortus-positive larval cultures were further examined for genetic polymorphisms associated with benzimidazole resistance at codons 167 and 200 of the β-tubulin isotype 1 gene by real-time pyrosequencing. Infections with H. contortus were detected in all four bison groups, as well as in mouflons. In five samples, representing two bison groups and the mouflons, the frequency of the resistance-associated single-nucleotide polymorphism (SNP) at codon 200 was 100%. In contrast, resistance-associated SNPs were not detected at codon 167. In addition, faecal egg counts from two bison before and 14 days after parenteral doramectin treatment indicated possible macrocyclic lactone resistance. Detection of anthelmintic resistant nematodes in these animals was especially concerning in the light of planned reintroduction into the wild. As helminth control in zoological gardens and wildlife parks relies mostly on anthelmintic treatment due to restricted possibilities regarding management practices such as rotational grazing, care should be taken to avoid underdosing or unnecessary frequent treatments facilitating the development of AR.

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.

Confounding factors affecting faecal egg count reduction as a measure of anthelmintic efficacy.

Increasing anthelmintic resistance (AR) in livestock has stimulated growing efforts to monitor anthelmintic effectiveness (AE) on livestock farms. On-farm assessment of AE relies on measuring the reduction in faecal egg count (FEC) following treatment; and if conducted rigorously, qualifies as a formal FEC reduction test (FECRT) for AR. Substantial research effort has been devoted to designing robust protocols for the FECRT and its statistical interpretation; however, a wide range of factors other than AR can affect FEC reduction on farms. These are not always possible to control, and can affect the outcome and repeatability of AE measurements and confound the on-farm classification of AR using FECRT. This review considers confounders of FEC reduction, focusing on gastrointestinal nematodes of ruminants, including host and parasite physiology and demography; pharmacokinetic variation between drugs, parasites and hosts; and technical performance. Drug formulation and delivery, host condition and diet, and seasonal variation in parasite species composition, can all affect AE and hence observed FEC reduction. Causes of variation in FEC reduction should be attenuated, but this is not always possible. Regular monitoring of AE can indicate a need to improve anthelmintic administration practices, and detect AR early in its progression. Careful interpretation of FEC reduction, however, taking into account possible confounders, is essential before attributing reduced FEC reduction to AR. Understanding of confounders of FEC reduction will complement advances in FECRT design and interpretation to provide measures of anthelmintic efficacy that are both rigorous and accessible.

Disclosing the bioactive metabolites involved in the in vitro anthelmintic effects of salt-tolerant plants through a combined approach using PVPP and HPLC-ESI-MSn

Strategies to reduce dependence on synthetic drugs for the treatment of gastrointestinal nematodes (GIN) infections in ruminants include the search for novel anthelmintic scaffolds on plants, yet salt-tolerant plants remain overlooked. This study aims to evaluate the in vitro anthelmintic properties of selected salt-tolerant plants against GIN, and identify the potential bioactive secondary metabolites involved. For that purpose, 80% acetone/water extracts were prepared from dried biomass of aerial organs of nine salt-tolerant plant species and tested against Haemonchus contortus and Trichostrongylus colubriformis by the Larval Exsheathment Inhibition Assay (LEIA) and Egg Hatching Inhibition Assay (EHIA). Pistacia lentiscus, Limoniatrum monopetalum, Cladium mariscus and Helychrisum italicum picardi were the most active in both GIN and life stages. To investigate the role of polyphenols in the anthelmintic activity, four selected extracts were treated with polyvinylpolypyrrolidone (PVPP), and non-treated and treated samples were further characterized by high-performance liquid chromatography with electrospray ionization mass spectrometric detection (HPLC-ESI-MSn). While polyphenols seem responsible for the EHIA properties, they are partially accountable to LEIA results. Several phenolics involved in the anthelmintic effects were identified and discussed. In sum, these species are rich sources of anthelmintic compounds and, therefore, are of major interest for nutraceutical and/or phytotherapeutic applications against GIN in ruminants.

Survival of the nematophagous fungus Duddingtonia flagrans to in vitro segments of sheep gastrointestinal tract

The nematophagous fungus Duddingtonia flagrans is used in integrated management of gastrointestinal nematodes in ruminants. The chlamydospores of the fungus, orally administered, pass through the segments of the ruminant digestive tract and, in the feces, capture the nematodes preventing their migration to grasslands. The drastic conditions of the gastrointestinal segments can negatively affect the fungus' biocontrol activity. The aim of this study was to assess the effect of in vitro conditions of the sheep's main gastrointestinal segments on the concentration, viability and nematode predatory ability of D. flagrans chlamydospores. The segments evaluated separately in vitro were the oral cavity, rumen, abomasum, and small intestine. The results showed that chlamydospores concentration was not affected by exposure to the different segments. The viability of the chlamydospores after exposure to the oral cavity (2.53 × 106 CFU/mL) and small intestine (1.24 × 105 CFU/mL) was significantly lower than its control treatment, with values of 6.67 × 106 CFU/mL and 2.31 × 105 CFU/mL respectively. Nematode predatory ability after rumen exposure was reduced by 7% compared to the control treatment, by 25% after abomasum exposure and by 17% after small intestine. This study revealed the individual in vitro effect of each segment of ovine gastrointestinal tract on the integrity of this strain of the fungus D. flagrans affecting its viability and nematode predatory ability under the evaluated conditions. Delivery systems could be designed to protect chlamydospores considering the impact of each gastrointestinal segment.

Control of gastrointestinal helminths in goats in a mixed grazing system with cattle

Due to the widespread resistance of small ruminant gastrointestinal nematodes (GIN) against anthelmintic drugs the established control strategies need to get adapted, aiming to reduce their high dependence from chemical drugs. Host-specific development of GIN can be used as a tool when grazing different species on the same pastures. The aim of this study was to estimate the effect of mixed grazing with cattle on the development of GIN infections in goats. Goat flocks with 3 heifers (Group Mix; Visp: n = 12, Chur: n = 15) and without heifers (Group Solo; Visp: n = 7, Chur: n = 15) were grazed separately on pastures at altitudes of 910 m (location Chur) and 1240 m (location Visp) above sea level resp. during one grazing season each. The composition of the mixed groups aimed to achieve a similar intake of roughage of both species. The stocking rate and the availability of roughage in the solo groups was balanced proportionately according to the situation in the mixed groups. The individual GIN egg excretion, the composition of the GIN larvae in the faeces, the FAMACHA©-Score and the pasture contamination with infective GIN larvae was determined in monthly intervals. At both sites the goats in the mixed groups showed a significantly lower mean GIN egg excretion compared with those of the Solo groups (p .