•Ivermectin efficacy was higher after oral compared to the intramuscular treatment.•Ivermectin plasma concentrations were greater after intramuscular administration.•The oral treatment increased the ...drug exposure of the gastrointestinal nematodes.
The goal of the current study was to evaluate the comparative efficacy of ivermectin (IVM) against small strongyles (cyathostomins) following its oral and intramuscular (IM) administration, in naturally parasitized horses. The parasitological data were complemented with the assessment of the plasma disposition kinetics of IVM. The trial included two different experiments. In experiment I, 40 horses naturally infected with small strongyles were randomly allocated into four experimental groups (n=10) and treated with IVM (0.2mg/kg) as follows: IVM oral paste, animals were orally treated with Eqvalan® (IVM 1.87% paste, as the reference formulation) by the oral route; IVM oral solution, animals were orally treated with Remonta® (IVM 2% solution, as a test formulation); IVM IM solution, animals were IM treated with the test product (Remonta® IVM 2% solution); and control, animals were kept without treatment as untreated controls. In experiment II, 24 horses naturally parasitized with small strongyles were randomly allocated into the same four experimental groups (n=6) described for experiment I. Faecal samples were individually collected directly from the rectum of each horse prior (day −1) and at 7 and 15 (Experiment I) or 7, 15 and 21 (Experiment II) days after-treatment, to assess the eggs per gram (epg) counts and estimate the efficacy of the treatments. Additionally, the comparative plasma disposition kinetics of IVM in treated animals was assessed in experiment II. In both experiments, an excellent (100%) IVM efficacy was observed after its oral administration (test and reference formulations). However, the IM administration of IVM resulted in a low efficacy (36–64%). Similar IVM plasma concentration was observed after its oral administration as a paste or as a solution. The higher IVM plasma profiles observed after the IM administration accounted for an enhanced systemic availability. The improved IVM efficacy observed against adult cyathostomins after its oral administration can be explained by an enhanced drug exposure of the worms located at the lumen of the large intestine. These findings may have a direct impact on the practical use of macrocyclic lactones in horses.
The efficacy of the nematode-trapping fungus
Duddingtonia flagrans
incorporated into an energy block was evaluated for the control of gastrointestinal nematodes in sheep. Four naturally parasitised ...sheep with average nematode egg counts of 2,470 eggs per gram grazed by pairs on two similar parasite-free paddocks for 30 days. During that period, one pair of sheep (treated animals, T1) received an energy block containing chlamydospores of
D. flagrans
at a dose of 200,000 chlamydopores/kg bw/day, while the second pair (control animals, C1) received a fungus-free energy block. The animals in both groups were taken off the paddocks after contaminating the pastures for a month with either nematode eggs plus fungal chlamydospores (T1) or nematode eggs alone (C1). Twelve parasite-free sheep were divided into two groups of six animals each, the treated group (T2) was placed on the paddock previously contaminated with parasites and fungus, while the control group (C2) was placed on the parasite-only paddock. These two groups grazed on their respective paddocks during 30 days and were then housed for 15 days, after which period they were slaughtered in order to determine the parasite burden present in each animal. Results showed that animals in group T2 harboured significantly less nematodes than their counterpart in group C2. The efficacy of
D. flagrans
was 92% against the total parasite burden, 100% against
Haemonchus contortus
and
Teladorsagia circumcincta
, 89.9% against
Trichostrongylus colubriformis
, 87.5% against
Cooperia onchopora
, and 90% against
Trichostrongylus axei
. No efficacy was detected against
Nematodirus spathiger
,
Trichuris ovis
and
T. skrjabini
.
Duddingtonia flagrans is a natural strain of Nematophagous-Fungi isolated around the world. It has demonstrated efficacy and ease of use in laboratory as well as in field conditions. The fungus ...contributes to the prophylactic control of the worms by reducing the number of L3 on pasture. The aims of this study were to test and analyze the predatory effect of D. flagrans under sunny and shaded conditions on the L3 in the faeces, and to verify the reduction of translation to pasture during summer and winter seasons. Faecal Mass Units (FMUs) were assigned to two treated groups (groups treated with D. flagrans chlamydospores, TG) and two untreated groups (without D. flagrans chlamydospores, UG), in summer and winter, under sunny and shaded conditions. FMUs and herbage samples were taken for parasitological workup. Predatory activity of D. flagrans was evident under both conditions for the summer experiment but was not manifest for the winter experiment. In summer, an interaction between sunny and shaded conditions and predatory activity of D. flagrans was found. Environmental conditions on predatory activity should be considered when designing strategies for the implementation of D. flagrans in grazing systems to smooth the infectivity curve of L3.
Display omitted
•The aim was to test Duddingtonia flagrans under different environmental conditions.•Predatory activity of Duddingtonia flagrans was evident in summer.•Predatory activity of Duddingtonia flagrans was not manifest in winter.•Predatory activity of D. flagrans was affected by the environment conditions.
The goal of the current experiment was to assess the clinical efficacy of oxfendazole (OFZ) administered as a single oral dose (30mg/kg) to pigs naturally parasitized with Ascaris suum, ...Oesophagostomum spp., Metastrongylus spp. and Trichuris suis. Thirty-six local ecotype piglets were divided into three independent experiments, named I, II and III (n=12 each), respectively. Each experiment involved two different groups (n=6): Untreated Control and OFZ treated. Animals were naturally parasitized with A. suum (Experiments I, II and III), Oesophagostomum spp. (Experiments I and II), T. suis (Experiments II and III) and Metastrongylus spp. (Experiment I). Pigs in the treated group received OFZ (Synanthic®, Merial Ltd., 9.06% suspension) orally at 30mg/kg dose. At five (5) days post-treatment, animals were sacrificed and the clinical efficacy of the OFZ treatment was established following the currently available WAAVP guidelines for a controlled efficacy test. None of the animals involved in this experiment showed any adverse events during the study. OFZ treatment given as a single 30mg/kg oral dose showed a 100% efficacy against all the nematode parasites present in the three experiments. In conclusion, under the current experimental conditions, OFZ orally administered to naturally parasitized piglets at a single dose of 30mg/kg was safe and highly efficacious (100%) against adult stages of A. suum, Oesophagostomum spp., T. suis and Metastrongylus spp.
The effect of ivermectin excreted in faeces of cattle treated in late winter on the arthropods and the degradation of faeces on pasture were evaluated. Four calves of similar age and weight were ...allocated to two groups, one group was treated subcutaneously with ivermectin and the other group remained as untreated control. From faeces collected from both groups at 3, 7, 14, 21 and 28 days post-treatment (dpt), three faecal pats of 1 kg each were made and deposited on a mixed paddock. One quarter of each faecal pat was removed at 10, 20, 30 and 60 days postdeposition (dpd) to determine the concentration of ivermectin, the organic matter content, and to collect colonising dung arthropods. Concentrations at days 3 and 7 pt were significantly higher than at the other dpt (
p
< 0.05). The highest ivermectin concentrations were found in samples from 3 dpt (
p
< 0.05). The organic matter percentage was not significantly different between treatments. An edaphic fauna characterised the colonisation of the faeces by organisms. Although arthropods’ abundance differences were not significant except for the 28 dpt at 30 dpd (
p
< 0.0003), fewer organisms were collected from the ivermectin group at all times.
Biological control of gastrointestinal nematodes of ruminants by use of nematophagous fungi would become part of any livestock parasite integral control system. Identifying autochthonous species that ...could then be selected for mass production is an important phase in the practical use of biological control.
To search for nematophagous fungi with potential use as biological control agents against gastrointestinal nematodes in Argentina.
Decomposing cattle faeces sampled in different locations were incubated in water agar 2% with Panagrellus sp. The developed nematophagous fungi were transferred to new water agar 2% plates and then to corn meal agar plates in order to carry out their identification. Fungal diversity and richness were also assessed.
Seventeen species from nine genera of nematophagous fungi were found. Twelve species were nematode-trapping fungi and three species plus two fungi identified to genus level corresponded to endoparasitic fungi. Arthrobotrys conoides, Arthrobotrys oligospora, Duddingtonia flagrans, Monacrosporium doedycoides, Arthrobotrys robusta and Drechmeria coniospora were the most frequently isolated species overall in the whole study (6.6%, 5.7%, 5.7%, 5.7%, 4.7% and 4.7%, respectively) although other species were more frequently recorded at local levels such as Arthrobotrys pyriformis (18.8%). Only A. conoides has been previously isolated from ruminant faecal samples in Argentina. Five nematode-trapping fungal species are mentioned for the first time in the Americas
D. flagrans and A. conoides, both identified in the present study, are among the most promising ones as biological control agents against gastrointestinal nematodes of ruminants.
The control of gastrointestinal nematodes relies at present mostly on antihelmintic treatments using synthetic molecules. This approach, however, has led to the appearance of resistance to some types ...of antihelmintics which, together with the need to cut down on the use of chemicals, has fostered the development of other control methods, such as biological control, which is the use of living organisms that are naturally antagonistic to an unwanted species. Among the natural enemies of nematode parasitic larvae is the microfungus Duddingtonia flagrans. Research has shown the ability of this fungus to reduce the number of nematode larvae in faeces, the ability of its chlamydospores to survive the passage through the gastrointestinal tract of livestock and, moreover, to keep its germinative ability, thus facilitating the development of formulations. The present review looks at the species currently used and the different ways of administering already tested nematophagous fungi.
The large-scale production of nematophagous fungi as agents of biological control is one of the main challenges to be commercially used. In order to improve growth of microorganism in a culture ...medium, the addition of growth inducer is common. At the moment, the action of their addition in the mycelia growth and sporulation rate of nematophagous fungi is not known. The purpose of this trial was to evaluate the sporulation rate of
Duddingtonia flagrans
by adding two growth inducers,
meso
-inositol and Tween 80, both at 0.5 % in a traditional culture medium Sabouraud glucose agar (SGA) and also in a traditional culture medium enriched with wheat flour and milk powder. From a traditional sterile culture of
D
.
flagrans
, four groups were made: SGA; Sabouraud glucose agar–
meso
-inositol 0.5 %; Sabouraud glucose agar–Tween 80 0.5 %; and Sabouraud glucose agar-enriched (SGA-E). These media were placed at a constant temperature of 27 °C for 4 weeks. Following this, chlamydospores were gently rinsed off with sterile water and counted using a Neubauer haematocytometer to estimate the number of chlamydospores per millilitre of water. The addition of
meso
-inositol 0.5 % to SGA promoted a significant increase (
p
< 0.05) in chlamydospore production obtaining an average of 51,715,000 chlamydospores per Petri dish. The highest chlamydospore concentration was observed in the SGA-E in comparison with SGA (
p
< 0.01) obtaining an average of 208,760,000 chlamydospores. The aim of this study was to obtain basic knowledge regarding the effect of enriched culture medium and growth-inducing
meso
-inositol and Tween 80 on mycelial growth and production of chlamydospores.
Se estudiaron bajo condiciones normales de manipuleo, las especies de pescados marinas Merluza, Abadejo, Corvina y Pescadilla que arribaron a Puerto Mar del Plata para su posterior transformación y/o ...consumo durante el período 1982-1992. En ellas se determinó la presencia de géneros de parásitos actuantes y su relación con las características de aptitud para el consumo, a través de los ensayos organolépticos, químicos de determinación de nitrógeno básico volátil y la composición centesimal. Los géneros de parásitos actuantes demostraron un neto predominio de Nematodos en Merluza y de Cestodos en Abadejo, Corvina y Pescadilla. Se hallaron además copépodos parásitos en Merluza y Abadejo, protozoarios parásitos en Merluza y acantocéfalos parásitos en Corvina y Pescadilla. Se determinó por medio de patrones organolépticos el grado de calidad de los pescados estudiados resultando el 100 por ciento aptos para el consumo. También se evaluó por medio de la determinación de nitrógeno básico volátil el grado de frescura, resultando el 100 por ciento de las muetras procesadas aptas para el consumo. Finalmente se evaluó la composición centesimal (Proteínas, grasas y humedad) no encontrándose diferencias significativas apreciables entre los animales parasitados y no parasitados.
During the period between 1962 and 1992 it were studied, in usual conditions of handling, the sea fishes Merluccius merluccius hubsii, Genypterus blacodes, Micropogon opercularis and Cynoscion striatus wich arrived to Mar del Plata port for the subsequent transformation and/or consumption. It was determined the presence of parasite genus and its relation with the characteristics of aptitude to consumptionby means of organoleptic test, quimic test to determine the volatile basic nitrogen and the body composition (percentage). The parasite genus showed a net predominance of nematodes in Merluccius merlucius hubsii and cestodes in Genypterus blacodes, Micropogon opercularis and Cynoscion striatus. It found also parasite copepods Merluccius M. hubsii and parasite acanthocephalan in Micropogon opercularis and Cunoscion striatus. By means of organoleptic patterns it was determined the quality degree of the fishes analyzed, resulting 100 per cent apt to consumption. Is was valued also the freshnessdegree by means of the volatile basic nitarogen determination, being all samples processed (100 per cent) apt to consumption. Finally it were valued the protein, fat and humidity percentages, there were not statistically different between the animals with parasites and those without parasites.
Machining of Titanium alloys (Ti6Al4V) becomes more vital due to its essential role in biomedical, aerospace, and many other industries owing to the enhanced engineering properties. In the current ...study, a Box-Behnken design of the response surface methodology (RSM) was used to investigate the performance of the abrasive water jet machining (AWJM) of Ti6Al4V. For process parameter optimization, a systematic strategy combining RSM and a heat-transfer search (HTS) algorithm was investigated. The nozzle traverse speed (T
), abrasive mass flow rate (A
), and stand-off distance (S
) were selected as AWJM variables, whereas the material removal rate (MRR), surface roughness (SR), and kerf taper angle (θ) were considered as output responses. Statistical models were developed for the response, and Analysis of variance (ANOVA) was executed for determining the robustness of responses. The single objective optimization result yielded a maximum MRR of 0.2304 g/min (at T
of 250 mm/min, A
of 500 g/min, and S
of 1.5 mm), a minimum SR of 2.99 µm, and a minimum θ of 1.72 (both responses at T
of 150 mm/min, A
of 500 g/min, and S
of 1.5 mm). A multi-objective HTS algorithm was implemented, and Pareto optimal points were produced. 3D and 2D plots were plotted using Pareto optimal points, which highlighted the non-dominant feasible solutions. The effectiveness of the suggested model was proved in predicting and optimizing the AWJM variables. The surface morphology of the machined surfaces was investigated using the scanning electron microscope. The confirmation test was performed using optimized cutting parameters to validate the results.
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