Consumption of nutritional pellets with Duddingtonia flagrans fungal chlamydospores reduces infective nematode larvae of Haemonchus contortus in faeces of Saint Croix lambs

Formulating Parasiticidal Fungi in Dried Edible Gelatins to Reduce the Risk of Infection by Trichuris sp. among Continuous Grazing Bison

Control of infection by gastrointestinal nematodes remains a big problem in ruminants under continuous grazing. For the purpose of decreasing the risk of infection by Trichuris sp. in captive bison (Bison bison) always maintained in the same plot, dried gelatins having ≥106 chlamydospores of both Mucor circinelloides and Duddingtonia flagrans were given to them for one week, and at the end, fecal samples (FF) collected each week for four weeks were analyzed immediately. Feces taken one week prior to gelatin administration served as controls (CF). Eggs of Trichuris sp. were sorted into non-viable and viable, then classified into viable undeveloped (VU), viable with cellular development (VCD), or viable infective (VI). Ovistatic and ovicidal effects were determined throughout the study. In FF, viability of Trichuris eggs decreased between 9% (first week) and 57% (fourth week), egg development was delayed during the first two weeks, and VI percentages were significantly lower than in CF (p = 0.001). It is concluded that the preparation of gelatins with chlamydospores of parasiticidal fungi and their subsequent dehydration offer an edible formulation that is ready to use, stress-free to supply, and easy to store, as well as being well-accepted by ruminants and highly efficient to reduce the risk of Trichuris sp. infection among animals under continuous grazing regimes.

Efficacy of Duddingtonia flagrans (Bioverm®) on the biological control of buffalo gastrointestinal nematodes

We evaluated the efficacy of Bioverm®, a commercial product containing Duddingtonia flagrans, on the control of buffalo (Bubalus bubalis) gastrointestinal nematodes. We randomly divided 12 buffaloes into two groups of six animals. In the treated group, each animal received a Bioverm®`s single dose of 1g (105 chlamydospores of D. flagrans) to 10 kg of live weight; in the control group, each animal received 1g of corn bran for each 10 kg of live weight as a placebo. Fecal samples were individually collected from 12, 24, 36, 48, 60 and 72 h after treatments. To examine 1) viability of chlamydospores passed through the gastrointestinal tract, 2 g of faeces and 1000 infective larvae (L3) were added to Petri dishes with 2% water-agar, and 2) to examine larval predation by D. flagrans during fecal cultures, 2000 L3 were added. In the Petri dishes, were observed significant reductions (p < 0.01) in the treated group after 48 (56.7%) and 60 h (91.5%). In the fecal cultures, significant reductions (p < 0.01) occurred in the treated group from 36 h (75%), with larval reduction up to 72 h. High larval predation rate occurred 60 h after Bioverm® administration. Bioverm® maintained viability and predation capacity after passage through the buffalo's gastrointestinal tract, showing efficacy on gastrointestinal nematodes.

Isolation of saprophytic filamentous fungi from avian fecal samples and assessment of its predatory activity on coccidian oocysts

Fungal strains used in the biocontrol of animal gastrointestinal parasites have been mainly isolated from pasture soil, decaying organic matter, and feces from herbivores and carnivores. However, their isolation from birds and assessment of predatory activity against avian GI parasites has been scarce thus far. This research aimed to isolate filamentous fungi from avian fecal samples and evaluate their predatory activity against coccidia. A pool of 58 fecal samples from chickens, laying hens, and peacocks, previously collected between July 2020-April 2021, were used for isolation of filamentous fungi and assessment of their in vitro predatory activity against coccidian oocysts, using Water-Agar medium and coprocultures. The Willis-flotation technique was also performed to obtain concentrated suspensions of oocysts. A total of seven Mucor isolates was obtained, being the only fungal taxa identified, and all presented lytic activity against coccidia. Isolates FR3, QP2 and SJ1 had significant coccidiostatic efficacies (inhibition of sporulation) higher than 70%, while isolates FR1, QP2 and QP1 had coccidicidal efficacies (destruction of the oocysts) of 22%, 14% and 8%, respectively, after 14 days of incubation, being a gradual and time-dependent process. To our knowledge, this is the first report regarding the isolation of native predatory fungi from avian feces and demonstration of their lytic activity against coccidia.

Are Anthelminthic Treatments of Captive Ruminants Necessary?

Anthelmintics are frequently administered to animals to limit fecal egg elimination, so that wild animals in captive breeding programs are treated to maintain a proper health condition. This is effective from a health management perspective, but on the other hand, it could prevent captive animals from developing an effective immunity against parasites that they might encounter when reintroduced into their original geographic areas. The aim of this study was to describe the dynamics of parasite infections in captive Cuvier’s gazelles (Gazella cuvieri) not treated with anthelmintics for two years and to evaluate the factors related to their fecal egg shedding. Fifteen one-year-old males were enclosed together and captured monthly to collect feces directly from the rectum. Fecal egg counts were performed, and eggs were classified as strongylid-like, Nematodirus sp., or Trichuris sp. Fecal egg shedding for the three groups of parasites did not vary significantly over the duration of the study. Only precipitation affected the egg-shedding pattern of all parasites, while inbreeding was positively associated with the number of strongylid-like parasites. These findings suggest an equilibrium between hosts and parasites in absence of treatment during the study. The anthelmintic treatment as a systematic prophylaxis method in captive animals should be avoided and replaced by systematic coprological and clinical vigilance, as well as targeted treatment in the case of a significant rise of fecal egg counts.

Control of Strongyles in First-Season Grazing Ewe Lambs by Integrating Deworming and Thrice-Weekly Administration of Parasiticidal Fungal Spores

Parasiticidal fungi have been used in several in vivo experiments in livestock farms worldwide, constituting an effective tool for the biocontrol of gastrointestinal parasites in grazing animals. In the first year of study, two groups of eight first-season pasturing ewe lambs infected by strongyles were dewormed with albendazole, and then, the test group received an oral dose of 10⁶ chlamydospores of Mucor circinelloides and 10⁶ Duddingtonia flagrans individually and thrice a week from mid-September to May (FS1), while the control group remained without fungi (CT1). In the second year, two new groups of first-season grazing ewe lambs were treated with ivermectin and subjected to the same experimental design (FS2 and CT2, respectively). The anthelmintic efficacy was 96.6% (CT1), 95.6% (FS1), 96.1% (CT2), and 95.1% (FS2). The counts of strongyle egg output increased in the control groups (CT1 and CT2) throughout the study and reached numbers higher than 600 eggs per gram of feces (EPG), while in FS1 and FS2, they were <250 EPG. The values of red blood cell parameters registered for CT1 and CT2 were lower than those of the reference standards, while a significant increment was recorded in FS1 and FS2, and values within the physiological range were attained. It is concluded that integrating efficient anthelminthic deworming with rotational pasturing and the regular intake of chlamydospores of M. circinelloides and D. flagrans provides a helpful strategy for maintaining low levels of strongyle egg output in first-season grazing ewe lambs and improves their health status.

Nematicidal activity of a hydroalcoholic extract of the edible mushroom Neolentinus ponderosus on L3 larvae of Haemonchus contortus

OBJECTIVE

In the present study, the in vitro and in vivo effect of the hydroalcoholic extract of Neolentinus ponderosus (EHNP) on L₃ larvae of Haemonchus contortus was evaluated.

MATERIAL AND METHODS

The N. ponderosus fungus was cultivated in potato dextrose liquid medium for 7 days at 120 rpm and 25 °C. Subsequently, the EHNP was obtained; in vitro bioassays were performed in 96-well plates. Furthermore, an in vitro confrontation with different concentrations of EHNP was carried out at 72 h against L3 larvae of H. contortus. The controls used were distilled water and ivermectin at 5 mg/mL. Subsequently, the in vivo activity of EHNP was evaluated using the gerbil against H. contortus L3 larvae as an experimental model. The experimental design consisted of four groups with: (1) distilled water, (2) fenbendazole at 20 mg/kg of body weight, (3) EHNP at a dose of 81 µg/mL, and (4) EHNP at a dose of 40 µg/mL.

RESULTS

In vitro study showed 97% mortality of the parasite H. contortus at a concentration of 3.4 mg/mL and a lethal concentration (LC90) of 2 mg/mL EHNP. In the in vivo assessment the highest mortality was (49%) at 72 h at a concentration of 81 µg/mL bw.

CONCLUSION

The result of the present study shows that EHNP has nematicidal activity in vitro and in vivo tests (close to 97% and 50%, respectively), the fungus N. ponderosus should be considered in future tests to elucidate the secondary metabolites through spectroscopic studies.

Effect of an Arthrobotrys musiformis (Fungi: Orbiliales) culture filtrate on the population of gastrointestinal parasitic nematode eggs in faeces of grazing lambs

This study assessed the anthelmintic activity of the oral administration of a free-spore culture filtrate of the nematophagous fungus (NF) Arthrobotrys musiformis (M-10) on gastrointestinal parasitic nematodes (GIN) in naturally infected lambs. The fungus was grown on potato-dextrose agar plates (PDA) and transferred to a fermented rice medium (FRM). After 40-day incubation the total amount of FRM with the growing fungi was transferred to a flask shaker with distilled water for a 24 h period. The fungus was centrifuged and filtered. Three groups of six naturally-infected lambs (>1000 epg) each were treated once as follows: Group 1) 63.8 mg/kg A. musiformis culture filtrate (CF) (per os); Group 2) Levamisole 7.5 mg/ml (intramuscularly), Group 3) 15 ml of distilled water (per os). Faecal samples were individually collected on days -2, 0, 2, 4, 6, 8 and 10 after treatment. For each experimental group, mean egg shedding was calculated and transformed (log 10 [epg + 1]). Means between the fungal filtrate group and the negative control were analysed using a T-Student Test. The faecal egg count reduction test (FECRT) was performed in groups treated with CF and Levamisole in relation to the control group (water) were 36.8-57.4% and 89-95.4%, respectively., although due to the difference between groups, no statistical significance was found (p > 0.05). The use of A. musiformis CF appears to be a good alternative treatment, although, more studies should be performed to establish the use of these fungal products as potential tools for GIN control.

Butlerius butleri (Nematoda: Diplogasteridae) Feeds on Haemonchus contortus (Nematoda: Trichostrongylidae) Infective Larvae and Free-Living Nematodes in Sheep Faecal Cultures Under Laboratory Conditions: Preliminary Report

AIM

This study assessed the feeding activity of the predatory nematode Butlerius butleri on the infective larvae of the sheep parasitic nematode Haemonchus contortus (Hc-L₃) and on two free-living nematodes Panagrellus redivivus (Pr) and Rhabditis sp. (R) in sterile sheep faecal cultures.

MATERIALS AND METHODS

A bioassay was carried out in sheep faecal cultures, where predatory and prey nematodes were put together to assess the predatory behaviour on the different nematodes. Faecal cultures (n = 9) were set up in different treatments as follows: Treatments 1, 2 and 3 contained 20 specimens of B. butleri and 2000 Hc-L₃, Pr and R, respectively; treatments 4, 5 and 6, contained only 2000 Hc-L₃, Pr and R, respectively, as control groups. Treatment 7 contained 20 B. butleri as control. All treatments were incubated at room temperature for 30 days. The average number of nematodes recovered from each treatment was obtained and the reduction rate with respect to their corresponding control was estimated. Data were analysed using an ANOVA test using a completely randomised design in the SAS programme.

RESULTS

Butlerius butleri reduced the Hc-L₃, population by 91.8%, whereas its population increased 131.6 times. The interactions between B. butleri and Pr and R resulted in 80.9% and 62.5% nematode reduction and B. butleri increased its populations 268.3 and 82.7 times, respectively. This experiment was performed only once, so this can be considered a preliminary report at this time.

CONCLUSION

This study provides evidence for the first time that B. butleri feeds on one of the most economically important nematodes of small ruminants, Hc-L₃.

Acacia farnesiana pods (plant: Fabaceae) possesses anti-parasitic compounds against Haemonchus contortus in female lambs

Acacia farnesiana pods are rich in secondary metabolites and their biological activities have been recorded as antibacterial, antioxidant and anthelmintic. Previously, an in vitro bioguided study showed the important ovicidal and larvicidal effects of an organic fraction (EtOAc-F) from a hydroalcoholic extract of A. farnesiana pods against Haemonchus contortus. The present study aimed to assess the in vivo anthelmintic effect of EtOAc-F from A. farnesiana pods on the H. contortus faecal egg elimination in female lambs and on the infective larvae (L₃) population reduction in coprocultures. The EtOAc-F was obtained from a hydroalcoholic extract from A. farnesiana pods through chromatographic procedures; additionally, some secondary compounds were identified using high-performance liquid chromatography (HPLC). Twenty-one 'Katahdin' crossbred female lambs ranging from three to four months of age, with body weights 21.9 ± 0.39 kg were used. Animals were orally infected with H. contortus (L₃) by a single dose of 350 L₃/kg BW. Three experimental groups (n = 7) were assigned as follows: 1) Control (untreated), 2) Albendazole, as a positive control (at 7.5 mg/kg BW, unique dose) and 3) EtOAc-F (at 100 mg/kg BW, once every third day, with three applications in total). Individual faecal samples were collected once a week for 5 weeks (at days 38, 45, 52, 59 and 66) post-treatment, to measure the faecal egg counts (FEC) and to obtain the H. contortus (L₃) population from faecal cultures. The highest FEC reduction caused by EtOAc-F was 67.7%; meanwhile, albendazole showed a total FEC reduction after the second week post-treatment (day 45). On the other hand, the fraction caused an important reduction in the larval population in coprocultures (54.3-68.5%). The phytochemical analysis revealed the presence of galloyl derivatives and flavonoids as major compounds. The A. farnesiana pods could serve as a natural anthelmintic for the control of H. contortus, and perhaps for controlling other parasites of veterinary importance.

In Vitro and In Vivo Nematicide Effect of Extract Fractions of Pleurotus djamor Against Haemonchus contortus

Sheep haemonchosis is a disease that causes anemia, diarrhea, weight loss, low production, and even death of young animals. This represents a negative economic impact on the livestock sector. For decades, chemicals have been used to control this parasitic disease; however, cases of anthelmintic resistance have increased around the world. For this reason, the search for control alternatives is necessary. Several studies have shown that edible mushrooms of Pleurotus genus have different medicinal properties, including nematicidal activity. In this study, the chromatographic fractionation of the hydroalcoholic extract of fruiting bodies Pleurotus djamor was carried out to identify and isolate the metabolites responsible for nematicidal activity. From the fractionation of the extract, the fraction PdR2 and the subfraction PdB were obtained, which were evaluated against Haemonchus contortus under in vitro conditions. The nematicidal effect of the fraction PdB in gerbils infected artificially with H. contortus was evaluated. Finally, the analysis of the PdB fraction by gas chromatography-mass spectrometry and nuclear magnetic resonance was carried out. The results showed that the PdB had 100% of egg hatching inhibition from 5 mg/mL. Regarding larvicidal activity, it presented >97.2% from 24 h to 20 mg/mL. The in vivo evaluation of the PdB fraction showed a reduction of H. contortus larvae of 92.56%. The compounds present in this fraction were the mixture of allitol and an unidentified terpene in a ratio of 9:1. The PdB fraction is a potential alternative for the control of H. contortus, where allitol and a terpene could be responsible for nematicidal activity.

The efficacy of predatory fungi on the control of gastrointestinal parasites in domestic and wild animals-A systematic review

BACKGROUND

Gastrointestinal parasites like nematodes are associated with significant impacts on animal health, causing poor growth rates, diseases and even death. Traditional parasite control includes the use of anthelmintic drugs, albeit being associated with drug resistance and ecotoxicity. In the last decade, biological control of parasites using nematophagous or predatory fungi has been increasingly studied, although systematic evidence of its efficacy is still lacking. The aim of this work was to assess the evidence of efficacy of nematophagous fungi in the control of nematodes and other gastrointestinal parasites in different animal species.

METHODS

Using the PICO method (Population, Intervention, Comparison and Outcomes), we performed a systematic review on the subject to search for original papers published between January 2006 and October 2019, written in English, and indexed in PubMed/Medline. Medical Subject Headings (MeSH) terms were used in the syntax. Papers were selected for detailed review based on title and abstract. Inclusion and exclusion criteria were applied, and relevant data were collected from the remaining papers.

RESULTS

The literature search retrieved 616 papers. Eighty-nine were submitted to a detailed review. In the end, 53 papers were included in the analysis. The studies were very heterogeneous, using different fungi, doses, frequency of administration, duration of treatment, host animals, and target parasites. Considering the 53 papers, 44 studies (83 % of the interventions) showed efficacy, with only 9 studies (17 %) showing no significant differences when compared to control.

CONCLUSION

With the increasing hazards of drug resistance and ecotoxicity, biological control with predatory fungi stands out as a good tool for future parasite management, whether as a complementary treatment or as an alternative to standard parasite control.

The Possible Biotechnological Use of Edible Mushroom Bioproducts for Controlling Plant and Animal Parasitic Nematodes

The present paper reviewed publications on the nematocidal activity of edible mushrooms (EM) and their potential use as sustainable tools for the control of parasitic nematodes affecting agriculture and livestock industry. Nematodes are organisms living in the soil and animals' guts where they may live as parasites severely affecting economically important crops and farm animals, thus causing economic losses to worldwide agriculture. Traditionally, parasitic nematodes have been controlled using commercial pesticides and anthelmintic (AH) drugs. Over the years, nematodes developed resistance to the AH drugs, reducing the usefulness of many commercial drugs. Also, the use of pesticides/anthelmintic drugs to control nematodes can have important negative impacts on the environment. Different EM have been not only used as food but also studied as alternative methods for controlling several diseases including parasitic nematodes. The present paper reviewed publications from the last decades about the nematocidal activity of EM and assessed their potential use as sustainable tools for the control of nematodes affecting agriculture and livestock industry. A reduced number of reports on the effect of EM against nematodes were found, and an even smaller number of reports regarding the potential AH activity of chemical compounds isolated from EM products were found. However, those studies have produced promising results that certainly deserve further investigation. It is concluded that EM, their fractions and extracts, and some compounds contained in them may have biotechnological application for the control of animal and plant parasitic nematodes.

In vitro predatory activity of nematophagous fungi isolated from water buffalo feces and from soil in the Mexican southeastern

Nematophagous fungi from the feces of water buffalo and soil from southeastern Mexico were isolated, and their in vitro predatory activity against Haemonchus contortus infective larvae (L3) (HcL3) was assessed. The fungi were isolated by sprinkling soil or feces on water agar plates. Six series of 10 Petri dishes containing a 7-day-old culture of each fungus and a series without fungi as the control were prepared. Five hundred HcL3 were added to each plate. The plates were incubated at room temperature. The average of recovered HcL3 was considered to estimate the larval reduction rate. Four nematophagous fungi isolates corresponding to Arthrobotrys oligospora, var microspora (strains 4-276, 269 and 50-80) and one identified as A. oligospora,var. oligospora (isolates 48-80) were obtained from water buffalo feces. From the soil, five isolates were isolated; three corresponded to A. musiformis (Bajío, Yumca and Macuspana isolates), and two isolates were identified as A. oligospora (Comalcalco and Jalapa de Méndez isolates). The predatory activity of isolates from water buffalo feces ranged between 85.9 and 100%. Meanwhile, the fungi from the soil ranged between 55.5 and 100% (p≤0.05). The nematophagous fungi obtained could have important implications in the control of parasites of importance in the livestock industry.

Acute Oral Toxicity of Vetom 21.77 Based on Duddingtonia Flagrans in Broiler Chickens

A 14-d study was undertaken to test the acute toxicity of a new preparation Vetom 21.77 based on the predacious fungus Duddingtonia flagrans. A total of 40 healthy 5-day-old broiler chickens (Hubbard F15, 100 ± 5 g), that had previously gone through a required 5-days adaptation to the environment, were orally dosed with the drug for 5 consecutive days at different doses, after which their health status was assessed daily up to the end of the experiment. According to the results, no substantial changes in the physiological state of the chickens were detected during the experiment. Internal organs weighing revealed no statistically significant differences between the groups, though weight coefficient values of internal organs of treated chickens slightly exceeded those of the control group. Some haematological parameters were significantly higher in the treatment group, without going beyond reference ranges. All chickens used in the experiment survived the study. The preparation has not produced any toxic effect even at a higher dose (4000 µL/kg bw/day). It is concluded that Vetom 21.77 pertains to preparations of IV toxicity class.

Implementation of Biological Control to the Integrated Control of Strongyle Infection among Wild Captive Equids in a Zoological Park

The integrated control of strongyles was assayed for a period of three years in wild equids (zebras, European donkeys, and African wild asses) captive in a zoo and infected by strongyles. During three years control of parasites consisted of deworming with ivermectin + praziquantel; equids also received every two days commercial nutritional pellets containing a blend of 10⁴ - 10⁵ spores of the fungi Mucor circinelloides + Duddingtonia flagrans per kg meal. Coprological analyses were done monthly to establish the counts of eggs of strongyles per gram of feces (EPG). The reductions in the fecal egg counts (FECR) and in the positive horses (PHR) were calculated fifteen days after deworming; the egg reappearance period (ERP) and the time elapsed from the previous deworming (TPD) were also recorded. Four anthelmintic treatments were administered during the assay, three times throughout the first 2 yrs, and another treatment during the last one. FECR values of 96-100% and 75-100% for the PHR were recorded. The ERP oscillated between eight and twenty-eight weeks, and the TPD ranged from four to eighteen months, increasing to the end of the trial. No side effects were observed in any of the equids. It is concluded that integrated control of strongyles among equids captive in a zoo can be developed by anthelmintic deworming together with the administration of pellets manufactured with spores of parasiticide fungi every two days.

In Vitro Lethal Activity of the Nematophagous Fungus Clonostachys rosea (Ascomycota: Hypocreales) against Nematodes of Five Different Taxa

This study was aimed to evaluate the in vitro lethal activity of the nematophagous fungi Clonostachys rosea against 5 nematodes species belonging to different taxa. Two groups of 35 Petri dishes (PD) each were divided into 5 series of 7 (PD). Group 1 (series 1, 2, 3, 4, and 5) contained only water agar; meanwhile group 2 plates (series 6, 7, 8, 9, and 10) contained C. rosea cultures growth on water agar. Every plate from the two groups was added with 500 nematodes corresponding to the following genera/specie: Haemonchus contortus, Caenorhabditis elegans, Rhabditis sp., Panagrellus redivivus, and Butlerius sp. After 5-day incubation at room temperature, free (nontrapped) larvae were recovered from plates using the Baermann funnel technique. Recovered nematodes were counted and compared with their proper controls. Results shown an important reduction percentage of the nematode population attributed to the fungal lethal activity as follows: H. contortus (L₃) 87.7%; C. elegans 94.7%; Rhabditis sp. 71.9%; P. redivivus 92.7%; and Butlerius sp. 100% (p ≤ 0.05). The activity showed by C. rosea against the H. contortus can be crucial for further studies focused to the biological control of sheep haemonchosis, although the environmental impact against beneficial nematodes should be evaluated.