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1.
Toxocara (Neoascaris) vitulorum is a gastrointestinal nematode parasite of young ruminants, responsible for high mortality rates in parasitized cattle and buffalo calves. The objective of this work was to compare the predatory capacity under laboratory conditions of four fungal isolates of the nematophagous fungus Pochonia chlamydosporia (VC1, VC4, VC5 and VC12) on T. vitulorum eggs in 2% water-agar (2% WA). T. vitulorum eggs were plated on 2% WA Petri dishes which contained cultured fungal isolates and control plates without fungi. After 10 and 15 days one hundred eggs were removed and classified according to the following parameters: type 1, biochemical and physiological effect without morphological damage to the eggshell, type 2, lytic effect with morphological alteration of the eggshell and embryo and type 3, lytic effect with morphological alteration of eggshell and embryo in addition to hyphal penetration and internal egg colonization. The fungal isolates were effective in the destruction of T. vitulorum eggs presenting the type 3 effect at 10 and 15 days after contact with the fungus. No nematophagous fungi were observed in the control group during the experiment. There was no variation in the predatory capacity of the fungal isolates (P?>?0.01) at the intervals of 10 and 15 days. These results indicate that P. chlamydosporia (VC1, VC4, VC5 and VC12) negatively influenced the development of T. vitulorum eggs and can be considered a potential candidate for the biological control of nematodes.  相似文献   

2.
Brazil has a herd of 212 million cattle and 171 million hectares of pastures that produce approximately 96 % of Brazilian beef. The Brazilian production system enables animal infection by endoparasites, which are considered one of the main obstacles for the development of this industry and are responsible for considerable economic losses. The control of parasitic diseases is performed via the administration of antiparasitic drugs, but they leave residues of the products in the treated animal, affect non-target organisms and select resistant strains of the parasites. The species D. flagrans and M. thaumasium are promising and sustainable alternatives for controlling gastrointestinal helminths of ruminants and other herbivores. In this study, we evaluated the efficacy of isolates of these species, formulated in a sodium alginate matrix and administered twice a week, to reduce the number of environmental infective larvae of gastrointestinal nematodes that affect prepubescent zebu females. The treated animals presented fewer eggs and a lower number of infective larvae per gram of faeces (p?<?0.05). The pastures occupied by treated animals showed a statistically significant reduction (p?<?0.05) of the number of L3 and, furthermore, the genera Cooperia sp., Haemonchus sp., and Oesophagostomum sp. were the most prevalent. The average weight of the animals did not differ statistically (p?>?0.05) among the treated and control groups. The use of sodium alginate pellets as vehicle for delivery of the fungus mycelia D. flagrans (isolate AC001) and M. thaumasium (isolate NF34A) proved effective in controlling trichostrongylids in prepubescent cows bred in the semi-arid region, with an effective reduction in the number of infective larvae in the pastures.  相似文献   

3.
The in vitro effect of an isolate of the nematophagous fungus Pochonia chlamydosporia (VC1) on the eggs of Anoplocephala perfoliata was evaluated. The eggs were morphologically analyzed for their integrity using light microscopy (10× objectives), plated on 9.0-cm diameter petri dishes containing 2% WA culture medium with and without fungal isolate (control), grown for 10 days, and 10 replicates were prepared per group. In all, 1000 eggs of A perfoliata were plated on petri dishes containing 2% water agar culture medium with (VC1) and without the fungal isolate (control). After 3, 5, 7, and 10 days, approximately 100 eggs were removed from each plate and classified on the basis of the following parameters: without alteration; type 1, lytic effect without morphological damage to eggshell; type 2, lytic effect with morphological alteration of embryo and eggshell; and type 3, lytic effect with morphological alteration of embryo and eggshell, in addition to hyphal penetration and internal egg colonization and destruction. The P chlamydosporia fungus demonstrated ovicidal activity (P < .05) on the eggs of A perfoliata in the studied intervals presenting type 3 effects of 35%, 42.5%, 53.83%, and 71.17% for the intervals 3, 5, 7, and 10 days, respectively. P chlamydosporia is a potential biological control agent for the eggs of A perfoliata.  相似文献   

4.
The ovicidal effect of the nematophagous fungus Pochonia chlamydosporia on eggs of Ascaris suum was tested under laboratory conditions. A. suum eggs were plated on 2% water–agar with seven fungal isolates (Isol. 5, Isol. 31, Isol. 1, VC1, Isol. 12, Isol. 22 and VC4) and control without fungus. After 5, 7, 10, 14, 15 and 21 days of incubation, approximately 100 eggs were removed from the plates and classified according to the following parameters: type 1, biochemical and physiological effect without morphological damage to the eggshell, type 2, lytic effect with morphological alteration of the eggshell and embryo and type 3, lytic effect with morphological alteration of eggshell and embryo showing hyphal penetration and internal egg colonization. The isolates effectively destroyed A. suum eggs and all types of effects were observed during the experiment. There was no variation in ovicidal capacity (type 3 effect) among the isolates (p > 0.05) throughout the experiment. After 21 days, isolate 5 showed the highest percentages of type 3 effect (58.33%). The results indicated that P. chlamydosporia (Isol. 5, Isol. 31, Isol. 1, VC1, Isol. 12, Isol. 22 and VC4) can destroy A. suum eggs and is, therefore, a potential biological control agent of nematodes.  相似文献   

5.
Biological control of gastrointestinal nematodiasis in ruminants is an alternative to reduce the number of infective larvae. The fungal isolates predatory activity preservation is a basic requirement for the success of this control type. The aim of this work is to evaluate the predatory capacity of the fungus Arthrobotrys robusta (isolate I-31), preserved on silica gel on infective larvae of Haemonchus contortus under laboratory conditions on 2 % water agar (2 % WA). In this essay, A. robusta storage on silica gel showed successful predatory activity on H. contortus L3 larvae (p?<?0.01) compared to the control group. Nematophagous fungi were not observed in the control group during the experiment. There was a significant reduction (p?<?0.01) of 73.84 % in the means of H. contortus (L3) recovered from treatment with isolate I-31 compared to the control without fungi. Results indicate that A. robusta (I-31) could survive stored on silica gel for at least 7 years and keep its predatory activity on H. contortus (L3).  相似文献   

6.
With worldwide development of anthelmintic resistance, alternative approaches to the chemotherapeutic dominant approach for the control of parasitic nematodes in sheep are urgently required. As natural enemies of nematodes, nematophagous fungi offer the exciting possibility of an alternative to the dominant anthelmintic approach for parasite control in ruminants. Permanent sheep pasture harbor a promising array of nematophagous fungi and merits further investigation. One hundred and fifty samples of soil, old and fresh faeces were collected from 10 Irish sheep pastures. The three methods employed for the isolation of nematophagous fungi include the Baermann technique, flotation method and the sprinkling–baiting technique. Twenty-nine nematophagous fungi were observed of which 12 were predacious and 17 were endoparasitic. The most prevalent fungi were Cystopage lateralis, Stylopage hadra, Drechmeria coniospora and Meristacrum asterosperum. Permanent sheep pasture is a good source of nematophagous fungi and hence may harbor potential biological control agents. Monacrosporium cionopaga, Duddingtonia flagrans, D. coniospora and Hirsutella rhoissilensis were detected in fresh faecal samples indicating they may have survived the gastrointestinal tract and therefore a viable option as a biological control agent.  相似文献   

7.
The aims were (a) to quantify the number of Duddingtonia flagrans chlamydospores per gram of faeces (CPG) recovered from sheep administered with different oral doses and, (b) to describe the relationship between CPG and eggs per gram of faeces (EPG) on the efficacy to reduce Haemonchus contortus infective larvae. Three doses of chlamydospores per kg BW were orally administered during seven days: (T1) non treated control group, (T2) 1 × 106, (T3) 2.5 × 106 and (T4) 5 × 106. Three lambs, infected with H. contortus, were used per group. Faeces were obtained from the rectum of each lamb during the fungal administration period (days 0–6) and for six days after that period. Four coproculture replicates were made from each animal in days 2, 4, 6, 8 and 10. A higher chlamydospore dose produced higher CPG in faeces (p < 0.05), but a clear dose dependent effect was not found either in the larvae reduction or in the CPG:EPG ratio. When ratios were re-analyzed, independently of the treatment groups of origin, a better efficacy was obtained with a ratio from 5 to 10 CPG:EPG and a higher ratio (>10 per egg) showed a lower reduction efficacy (p < 0.05). The binomial analysis showed that for each unit of increment in CPG:EPG ratio there was a reduction of larvae number until a point (between 5 and 10 CPG:EPG) where no further reduction was detected. The surface response test indicated that the number of larvae was reduced by CPG until possible saturation. The highest CPG:EPG ratios did not necessarily improve efficacy of D. flagrans.  相似文献   

8.
Four isolates of predacious fungi, two each of Arthrobotrys oligospora isolated from a sheep and a male crossbred calf and of Duddingtonia flagrans isolated from a sheep and a female buffalo in western India, were studied for their suitability as biocontrol agents against parasitic nematodes of ruminants, using growth assay, predatory activity, germination potential and ability to survive passing through the ruminants gut as criteria. The study showed that isolates of D. flagrans grew well in artificial media, had encouraging predatory activity, produced profuse chlamydospores that germinated easily at 25°C and could survive passage through the ruminant gut. The ovine isolate of D. flagrans was superior in all respects to the isolate from buffalo and was the most promising candidate for biological control of nematode parasites of ruminants.  相似文献   

9.
This work was performed to determine the predatory capacity in vitro of the nematophagous fungus Duddingtonia flagrans (isolate AC001) on cyathostomin infective larvae of horse (L3). The experimental assay was carried out on plates with 2% water-agar (2% WA). In the treated group, each plate contained 1.000 L3 and 1.000 conidia of the fungus. The control group without fungus only contained 1.000 L3 in the plates. Ten random fields (4 mm diameter) were examined per plate of treated and control groups, every 24 h for seven days under an optical microscope (10× and 40× objective lens) for non-predated L3 counts. After 7 days, the non-predated L3 were recovered from the Petri dishes using the Baermann method. The interaction there was a significant reduction (p < 0.01) of 93.64% in the cyathostomin L3 recovered. The results showed that the D. flagrans is a potential candidate to the biological control of horse cyathostomin L3.  相似文献   

10.
The main goal in this research was to determine the beneficial effect of incorporating biological procedures in parasite control programs for equids in zoological parks. Two trials were developed for Equus quagga, E asinus , and E africanus asinus. The first trial (September 2010 to August 2011) consisted of chemotherapy only (ivermectin plus praziquantel), and the second trial (September 2011 to September 2012) consisted of administration of chemotherapy and chlamydospores of the nematophagous fungus Arthrobotrys (Duddingtonia) flagrans. The effect of these measures was evaluated by the estimation of the reduction in the fecal egg counts (FECR). In the first trial, 100% FECR values were achieved 15 days after treatment in all the animals. The egg reappearance period (ERP) was 2-3 months for the equids, and all of them were passing strongyle eggs in the feces at 2-4 months after their deworming. In the second experiment, the FECR values were 100% in the three species. ERPs of 3 months in the European donkeys, 4 months in the Africans, and 6 months in the zebras were recorded. All the equids had positive results for the coprological flotation test 4-8 months after anthelmintic administration. This preliminary study demonstrates the incorporation of chlamydospores of nematophagous fungus, as A flagrans appears highly promising for reduction of the infective stages of the strongyles affecting captive animals, but the experimental design precludes true determination of whether the treatment is fully efficacious.  相似文献   

11.
Ascaris suum is a gastrointestinal nematode parasite of swines. The aim of this study was to observe Pochonia chlamydosporia fungus on biological control of A. suum eggs after fungus passage through swines gastrointestinal tract. Eighteen pigs, previously dewormed, were randomly divided into three groups: group 1, treated with the fungus isolate VC4; group 2, treated with the fungus isolate VC1 and group 3 did not receive fungus (control). In the treated groups, each animal received a 9 g single dose of mycelium mass containing P. chlamydosporia (VC1 or VC4). Thereafter, animal fecal samples were collected at the following intervals: 8, 12, 24, 36, 48, 72 and 96 h after treatment beginning and these were poured in Petri dishes containing 2% water-agar culture medium. Then, 1,000 A. suum eggs were poured into each dish and kept in an incubator at 26°C and in the dark for 30 days. After this period, approximately 100 eggs were removed from each Petri dish and morphologically analyzed under light microscopy following the ovicidal activity parameters. The higher percentage observed for isolated VC4 eggs destruction was 57.5% (36 h) after fungus administration and for isolate VC1 this percentage was 45.8% (24 h and 72 h) (p > 0.01). P. chlamydosporia remained viable after passing through the gastrointestinal tract of swines, maintaining its ability of destroying A. suum eggs.  相似文献   

12.
The aim of this study was to investigate the effect of the nematophagous fungus Duddingtonia flagrans applied orally to small ruminants in a field study in Germany.  相似文献   

13.
One isolate of predator fungi Duddingtonia flagrans (AC001) was assessed in vitro regarding the capacity of supporting the passage through pigs' gastrointestinal tract without loss of the ability of preying infective larvae Oesophagostomum spp. Fungal isolates survived the passage and were efficient in preying L3 since the first 8 h of collection (p < 0.01) in relation to the control group (without fungus). Compared with control, there was a significant decrease (p < 0.01) of 59.6% (8 h), 71.7% (12 h), 76.8% (24 h), 81.0% (36 h), 78.0% (48 h), 76.1% (72 h), and 82.7% (96 h) in means of infective larvae Oesophagostomum spp. recovered from treatments with isolate AC001. Linear regression coefficients of L3 of recovered Oesophagostomum spp. regarding the collections due to time were −0.621 for control, −1.40 for AC001, and −2.64 for NF34. Fungi D. flagrans (AC001) had demonstrated to be promising for use in the biological control of pig parasite Oesophagostomum spp.  相似文献   

14.
The predatory capacity of the nematophagous fungus Pochonia chlamydosporia (isolate VC4) after passage through the gastrointestinal tract of dogs was assessed in vivo against Toxocara canis eggs. Twelve dogs previously wormed were divided into two groups of six animals and caged. The treatments consisted of a fungus-treated group (VC4) and a control group without fungus. Each dog of the fungus-treated group received a single 4 g dose of mycelial mass of P. chlamydosporia (VC4). Fecal samples from animals of both groups (treated and control) were collected at five different times (6, 12, 24, 36, and 48 h) after fungal administration, and placed in Petri dishes. Each Petri dish of both groups for each studied time interval received approximately 1000 T. canis eggs. Thirty days after the fecal samples were collected, approximately one hundred eggs were removed from each Petri dish of each studied time interval and evaluated by light microscopy (LM) and scanning electron microscopy (SEM). Microscopy examination of plates inoculated with the fungus showed that the isolate VC4 was able to destroy the T. canis eggs with destruction percentages of 28.6% (6 h), 29.1% (12 h), 32.0% (24 h), 31.7% (36 h), and 37.2% (48 h). These results suggest that P. chlamydosporia can be used as a tool for the biological control of T. canis eggs in feces of contaminated dogs.  相似文献   

15.
Abstract

AIM: To describe the seasonal pattern of development of third-stage infective larvae (L3) from eggs of Teladorsagia (=Ostertagia) circumcincta, Trichostrongylus colubriformis and Haemonchus contortus on pasture in the North Island of New Zealand.

METHODS: Sheep faeces containing known numbers of eggs of all three nematode species were deposited on, or buried in, pasture plots at three sites, viz coastal Manawatu, Upper Hutt Valley, and East Cape hill country. Development was measured by recovering L3 from faeces, herbage and soil 28–31 days after deposition on 13–18 occasions, between January 2005 and July 2006. Analysis of the number of larvae recovered used a mixed model including number of eggs deposited, weight of faeces recovered (an assumed indicator of earthworm activity), site, contamination date, and position of deposited faeces, i.e. on the surface or buried.

RESULTS: There was a significant effect of contamination date on development of all three species, with maximum numbers ofL3 developing between late spring (November) and early autumn (March), and minimum numbers in June and July. There were large differences between species, with H. contortus exhibiting a long period (April to October) where development was close to zero, whereas T. circumcincta developed to some extent all year round. Development of T. colubriformis was intermediate between the other two species.

Burying faeces containing nematode eggs increased the number of L3 recovered compared with surface deposition (p≤0.001), although there were a small number of exceptions involving only T. colubriformis. The weight of faeces recovered at harvest, which was assumed to be an indication of earthworm activity, was correlated with the number of L3 recovered for all species (p<0.001). In a separate analysis, earthworms were assumed tohave been active if <5 g faeces remained at harvest. Where this occurred, the number of L3 of T. colubriformis and T.circumcincta recovered was reduced by 56% and 58%, respectively (p<0.001).

CONCLUSIONS: A marked seasonal pattern of development was observed for all three species, with the most larvae developing in spring-early autumn and the least in winter. This seasonal pattern was most pronounced in H. contortus and least obvious in T. circumcincta. Burying faeces containing eggs generally resulted in more L3 being recovered, whilst the apparent activity of earthworms resulted in fewer larvae being recovered.  相似文献   

16.
In ovo feeding of vitamin C (VC) has positive effects on the growth performance, immune and antioxidant function in poultry, which indicates that increasing VC content in eggs may be of benefit. This study was to investigate the effects of dietary VC supplementation on VC synthesis and transportation and egg deposition. In Exp. 1, in order to select a suitable animal model, VC content was detected in different eggs from different layer species. Vitamin C content was lower in ISA Brown breeder eggs and Hy-Line Brown layer eggs (P < 0.05) then in Arbor Acres breeder eggs. In Exp. 2, a total of 24 Hy-Line Brown layers (42-week-old) were randomly divided into 3 treatments with 8 replicates and fed a basal diet with VC at 0, 200 and 400 mg/kg. Sodium-dependent VC transporter 1 and 2 (SVCT1 and SVCT2) expressions were higher in ileum than in duodenum and jejunum (P < 0.05). SVCT1 expression was higher but SVCT2 expression was lower in the magnum than in the ovary (P < 0.05). L-Gulonolactone oxidase (GLO) and SVCT1 expressions were higher but SVCT2 was lower in the kidney than in the liver (P < 0.05). Dietary VC supplementation at 400 mg/kg increased SVCT1 expression in duodenum, ovary and magnum, but decreased GLO and SVCT1 expression in liver (P < 0.05). Dietary VC supplementation at 200 and 400 mg/kg increased SVCT2 expression in duodenum, but decreased GLO and SVCT1 expression in kidney and SVCT2 expression in liver (P < 0.05). Dietary VC supplementation promoted VC absorption in duodenum and jejunum, but reduced endogenous VC synthesis in liver and kidney. Although dietary VC supplementation enhanced VC transportation in ovary and magnum, it did not increase VC deposition in produced eggs.  相似文献   

17.
The immunogenic properties of cysteine proteases obtained from excretory/secretory products (ES) of Haemonchus contortus were investigated with a fraction purified with a recombinant H. contortus cystatin affinity column. The enrichment of H. contortus ES for cysteine protease was confirmed with substrate SDS-PAGE gels since the cystatin-binding fraction activity was three times higher than total ES, despite representing only 3% of total ES. This activity was inhibited by a specific cysteine protease inhibitor (E64) and by recombinant cystatin. The one-dimensional profile of the cystatin-binding fraction displayed a single band with a molecular mass of 43 kDa. Mass spectrometry showed this to be AC-5, a cathepsin B-like cysteine protease which had not been identified in ES products of H. contortus before. The cystatin binding fraction was tested as an immunogen in lambs which were vaccinated three times (week 0, 2.5 and 5), challenged with 10 000 L3 H. contortus (week 6) before necropsy and compared to unvaccinated challenge controls and another group given total ES (n = 10 per group). The group vaccinated with cystatin-binding proteins showed 36% and 32% mean worm burden and eggs per gram of faeces (EPG) reductions, respectively, compared to the controls but total ES was almost without effect. After challenge the cystatin-binding proteins induced significantly higher local and systemic ES specific IgA and IgG responses.  相似文献   

18.
Tabernaemontana citrifolia (Apocynaceae) is traditionally used as an anthelmintic preparation for ruminants in Guadeloupe (French West Indies). This study was carried out to evaluate the in vitro effect of this plant against the parasitic nematode of small ruminants Haemonchus contortus. Three extracts (aqueous, methanolic and dichloromethane) of T. citrifolia fruit, leaf and root were tested on four developmental stages of the parasite, using egg hatch assay (EHA), larval development assay (LDA), L3 migration inhibition assay (LMI), and adult worm motility assay (AWM). Compared to the negative control, significant effects were observed for the different parts of T. citrifolia but with differences depending on the parasitic stage; efficacies on the larval development of H. contortus from 88.9% to 99.8% for fruit, from 72.1% to 83.8% for root and from 33.5% to 85% for leaf with dose-dependent effect for the methanolic extract. The root gave the best result on EHA (22.7% efficacy for dichloromethane extract) and AWM (56% efficacy, with dose-dependent effect for dichloromethane extract) and the leaf on LMI (49.4% efficacy). These results suggest that T. citrifolia possess anthelmintic activity against H. contortus. The active ingredients responsible for the activity could be the alkaloid compounds present in the plant parts of the plant.  相似文献   

19.
Feeding trials were conducted with stall-fed sheep parasitized with Haemonchus contortus. For 10 days they were offered 250 g of a concentrate feed that had been top-dressed with desiccated chlamydospores of Duddingtonia flagrans at 1×105, 5×105, 1×106 or 2×106 chlamydospores/kg body weight. Pooled faeces from each group on day 7 of spore feeding were spread on different pasture plots. On day 28 after the start of spore feeding, further pooled faeces from each group were spread on the same plots. The larval burdens on the plots were monitored for 2 months and the larval harvest from in vitro faecal cultures were monitored regularly. The application of 1×106 or more spores/kg body weight virtually eliminated larvae from both the pasture and the faecal cultures. The application of as few as 1×105 spores/kg body weight had a profound impact on larval recovery. The effect persisted while the spores were being fed but not for more than 4 days following discontinuation of spore feeding. Top dressing supplementary feed with dried chlamydospores offers a potential way of using D. flagrans for biological control of the pre-parasitic stages of H. contortus.  相似文献   

20.
Two experiments were conducted to determine whether the proanthocyanidin (condensed tannin)-containing forage legumes Desmodium intortum cv Greenleaf and Sesbania sesban (accession 15019) could be integrated into a feeding management strategy as a means of Haemonchus contortus control in goats. The anthelmintic effects of condensed tannin extracts from the two legumes on H. contortus L3 larvae were studied in an in vitro larval migration inhibition system. The extracts inhibited larval migration in a dose-dependent manner, and at concentrations from 1,000???g/ml condensed tannin, the extract from D. intortum caused a significantly higher inhibition of larval migration than did the corresponding concentrations of the S. sesban extract (P?<?0.01). Prolonged feeding of tanniniferous forage legumes showed that animals receiving D. intortum had the lowest total worm burden, the lowest female to male parasite ratio, the lowest number of eggs in the uterus of each female worm and the lowest per capita fecundity (P?<?0.01). However, there was no change in the performance (weight gain) of parasite-infected goats probably due to incomplete removal of the parasite or prolonged confinement of goats in small pens, which calls for further investigation. However, since there is no single efficient method in control of parasites, based on the obtained data from this experiment, integrated feeding of D. intortum with other suitable method of parasite control is thus suggested.  相似文献   

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