嗜线虫真菌Duddingtonia flagrans防制绵羊胃肠道线虫病

将 30只 4～ 6月龄羊分为 2组 ,分别在各自的围栏草场中放牧。用毛圆线虫和血矛线虫为主的第 3期幼虫对所有羊只人工感染 2次后 ,一组羊按每千克体重 1× 10 6 个的剂量每天饲喂嗜线虫真菌的厚垣孢子制剂 ;另一组羊作对照 ,仅饲喂等量的上述制剂基质——小麦。第 2次人工感染后 8周 ,2组羊粪便 EPG基本相近 ,但与对照组相比较 ,真菌组粪便培养物中感染性幼虫减少了 6 9.7% ;草场草样中感染性幼虫数也较对照组减少 6 7.8%。再把以上 2组羊驱虫后分别放养于上述围栏草场 ,8周后真菌组羊粪便 EPG较对照组减少 87.3% ;草场感染性幼虫也较对照组减少82 .6 %。上述结果显示 ,嗜线虫真菌 Duddingtonia flagrans在绵羊胃肠道寄生性线虫病生物防制中具有良好的应用前景     

嗜线虫真菌Duddingtonia flagrans保存方法的研究

目的探讨嗜线虫真菌Duddingtonia flagrans长期保存以及复苏后生物学活性测定技术。方法分别将菌株置4℃、-25℃和液氮保存,定期进行菌落生长速度、厚垣孢子生成时间以及捕杀绵羊粪便中感染性幼虫活性测定。结果4℃保存15个月、-25℃保存30个月以及液氮保存5年对该菌生长和捕杀感染性幼虫能力无明显影响。结论嗜线虫真菌D.flagrans具有较高的生物学稳定性。     

嗜线虫真菌Duddingtonia flagrans培养基的筛选

2000年新疆畜牧科学院从丹麦皇家农业和兽医大学引进了Duddingtonia flagrans菌株,经过3年多的研究,对该真菌进行了实验室驯化、基础培养、生物学特性和体内外捕杀新疆牛羊胃肠道线虫的效果检测。结果表明该真菌具有与国外研究一致的良好的生物防治效果。嗜线虫真菌D.flagrans经培养后产生大量的厚垣孢子能通过动物的胃肠道不被消化而随粪便一起排出体外,在适宜条件下该厚     

嗜线虫真菌制剂研制及其防治绵羊胃肠道线虫病的效果

用WA或PA琼脂平板制备嗜线虫真菌一级种子,用以小麦为基质加土豆汁的固体培养基或以土豆汁、微量盐为基础的液体培养基制备二级种子。再以上述固体培养基进行扩大培养,26℃培养3-4周,制剂厚垣孢子量可达1×106/g。研究了该制剂不经胃肠道和经胃肠道捕杀幼虫的生物学活性。用1×106/kg体重的剂量饲喂绵羊,对围栏草场中人工感染胃肠道线虫的绵羊进行生物防治临床效果观察,试验组羊克粪便虫卵数较对照组减少87.5%,草场中感染性幼虫减少82.6%,该制剂对绵羊胃肠道线虫病有良好的生物防治效果。     

嗜线虫真菌中Duddingtonia flagrans培养性状的初步研究

研究嗜线虫真菌中Duddingtonia flagrans在不同生长环境中的培养特性.选择普通琼脂培养基(WA)、玉米琼脂培养基(CMA)、马铃薯琼脂培养基(PA)和面粉琼脂培养基(FA)4种不同培养基培养,结果表明,在WA中真菌生长速度最快,在PA中产孢量最多.从应用的角度考虑,PA为最佳培养基;以10～35 C每隔5℃设置7种不同温度组培养,结果表明,10℃和35℃时不生长,25℃和30℃时菌丝生长率较高,产孢量较多,其中以30℃培养效果最好.     

嗜线虫真菌捕食绵羊粪便中捻转血矛线虫幼虫的效果观察

采集感染捻转血柔线虫等胃肠道线虫绵羊粪便培养、分离三期幼虫，加入嗜线虫真菌纯培养物中，72h后84％的幼虫被真菌丝绕和捕获；将该真菌培养物与感染捻转向矛线虫等胃肠道线虫的绵羊粪便便混合后共同培养10d，粪便培养物中的三期幼虫减少82％。     

用嗜线虫真菌防治家畜胃肠道线虫病的研究进展

简要论述了嗜线虫真菌种类及其捕捉器官和国内外生物防治家畜胃肠道线虫病的研究进展。国内外防治该病主要是用各种驱虫药物定期驱虫，由此造成寄生虫抗药性、动物组织残留药物、环境污染、线虫反复感染等诸多负作用。用线虫天敌嗜线虫真菌生物防治家畜胃肠道线虫病成为该领域研究的重点课题之一。实验室和野外的大量研究结果证明，嗜线虫真菌在通过动物胃肠道时能不被消化，从而保持活性，在粪便中能有效捕食营自由生活阶段的线虫幼虫，使放牧草场中感染性线虫幼虫明显减少，呈现出良好的生物防治效果。文章重点介绍了嗜线虫真菌Duddingtonia flagrans，对用嗜线虫真菌生物防治家畜胃肠道线虫病的前景充满信心。     

食动物线虫真菌的分离和鉴定I.从土壤中分离捕食线虫真菌

以山羊捻转血矛线虫第三期幼虫作为诱饵线虫,利用撒布分离法,对土壤中的食线虫真菌进行了分离和鉴定。结果从不同的土样中分离到了棣属于２个属,７个种的２６株捕食线虫真菌。７个真菌种分别为寡孢节丛孢菌（Ａｒｔｈｒｏｂｏｔｒｙ ｏｌｉｇｏｓｐｏｒａ）,指状节丛孢菌（Ａ．ｄａｃｔｙｌｏｄｅｓ）,蠕虫节丛孢菌（Ａ．ｖｅｒｍｉｃｏｌａ）,圆锥节丛孢菌（Ａ．ｃｏｎｏｉｄｅｓ）,白色单顶孢菌（Ｍｏｎａｃｒｏｓｐｏｒｉ     

绵羊捻转血矛线虫细颈线虫食道口线虫及其组织期幼虫季节动态观察

绵羊捻转血矛线虫细颈线虫食道口线虫及其组织期幼虫季节动态观察宗泽君汪作民石剑华（内蒙古赤峰市畜牧兽医科学研究所，０２４０３１）斯钦昭日格（内蒙古巴林右旗幸福之路苏木兽医站，赤峰０２５１５７）昭日格图（内蒙古巴林右旗巴彦他拉苏木兽医站，赤峰０２５１５６...     

捕食线虫性真菌Duddingtonia flagrans冻干制剂临床模式

本试验选用耐高温高压的菌种袋作为玉米粒培养基的培养容器,对Duddingtonia flagrans厚壁孢子进行批量培养,然后经孢子洗脱液将孢子洗脱后,将其制备成冻干制剂,并在内蒙古地区的呼和浩特市和林格尔、包头市萨拉齐、呼伦贝尔西旗等地养殖场共165头绵羊中进行了临床应用研究。通过设立不同的试验组和对照组,使用常用驱虫药伊维菌素进行驱虫试验,同时配合口服捕食线虫性真菌Duddingtonia flagrans厚壁孢子,在不同时间进行动物直肠采粪,对粪便进行第三期幼虫培养,然后检测比较不同组别粪便中感染性幼虫的数量,评价捕食线虫性真菌临床应用模式效果。结果显示,将伊维菌素与D.flagrans冻干制剂联合应用于绵羊的寄生性线虫病防治,可使粪便中幼虫数量降低100%,效果优于单独用药组。结果表明,捕食线虫性真菌Duddingtonia flagrans冻干生物制剂与驱虫药物联合使用的临床应用模式,可以取得较好的家畜线虫病临床防控效果,值得进一步在生产实践中进行深入研究和推广。     

The efficacy of two isolates of the nematode-trapping fungus Duddingtonia flagrans against Dictyocaulus viviparus larvae in faeces.

A series of experiments was carried out to examine the effects of two different isolates of the nematode-trapping fungus Duddingtonia flagrans to reduce the number of free-living larvae of the bovine lungworm, Dictyocaulus viviparus. A laboratory dose-titration assay showed that isolates CI3 and Troll A of D. flagrans significantly reduced (P < 0.05 to P < 0.001) the number of infective D. viviparus larvae in cultures at dose-levels of 6250 and 12,500 chlamydospores/g of faeces. The larval reduction capacity was significantly higher for Troll A compared to CI3 when lungworm larvae were mixed in faecal cultures with eggs of Cooperia oncophora or Ostertagia ostertagi and treated with 6250 chlamydospores/g of faeces. Both fungal isolates showed a stronger effect on gastrointestinal larvae than on lungworm larvae. Two plot trials conducted in 1996 and 1997 involved deposition of artificial faecal pats containing free-living stages of D. viviparus and C. oncophora on grass plots. Herbage around the pats was collected at regular intervals and infective larvae recovered, counted and identified. These experiments showed that both D. flagrans isolates reduced the number of gastrointestinal as well as lungworm larvae in faecal pats. During both plot trials, the transmission of C. oncophora larvae, but not D. viviparus, from faecal pats to the surrounding herbage was clearly affected by climatic conditions. After collection of faecal pats from the grass plots one month after deposition, the wet and dry weight of pats as well as organic matter content were determined. No differences were found between the fungus-treated and non-treated control pats. This indicated that the rate of degradation of faeces was not affected by the addition of the fungus.     

Evaluation of Duddingtonia flagrans in reducing infective larvae of Haemonchus contortus in feces of sheep.

Consequences of nematode infections due to Haemonchus contortus are a serious constraint for the sheep industry worldwide. Development of anthelmintic resistance and increasing concern about the impact of anthelmintic use dictate the need of alternative control. Such an alternative is using the nematode trapping fungus Duddingtonia flagrans to reduce infective larvae levels on pasture. Two trials were conducted to determine the effect of D. flagrans in reducing infective larvae (predominantly H. contortus) in feces. The first trial determined the dose effect of D. flagrans in reducing infective larvae in feces. Eighteen ewes were dewormed to remove existing infections and randomly assigned to six treatment groups: 5 x 10(4), 1 x 10(5), 2.5 x 10(5), 5 x 10(5), 1 x 10(6) or no (control) spores of D. flagrans per kg of body weight mixed in their feed for 7 days. Fecal samples were collected daily from these and from infected donor ewes. Feces from individual-treated ewes were mixed with equal amounts of donor ewe feces, theoretically approximating oral dose spore concentrations of 2.5 x 10(4), 5 x 10(4), 1.25 x 10(5), 2.5 x 10(5), 5 x 10(5) and no spores, and were cultured. Across dosages and during the 7 days of fungus feeding, percent reduction of infective larvae ranged from 76.6 to 100.0%. The second trial determined the effect of D. flagrans at the dose of 10(5) spores per kg body weight on reducing infective larvae in feces from naturally infected lambs. Twenty lambs were randomly assigned to either treatment or control groups based on fecal egg count. Treatment lambs were fed spores mixed in feed for 7 days. Feces were collected daily and cultured. During the 7 days of fungus feeding, the percent reduction of infective larvae ranged from 82.8 to 99.7%. Results of these trials demonstrated that the nematode trapping fungus D. flagrans was highly effective in reducing infective larvae in sheep feces and should be considered as a biological control agent for integrated nematode control programs.     

捕食性真菌Duddingtonia flagrans原生质体的快速制备与再生

为快速获得大量捕食性真菌Duddingtonia flagrans原生质体并使其再生,本试验研究了酶质量浓度、酶解温度、菌龄、酶解时间对D.flagrans原生质体产生的影响,以确定D.flagrans原生质体最佳快速制备条件。结果表明,在溶壁酶2mL/L、蜗牛酶8g/L、纤维素酶8g/L时,35℃恒温条件下,酶解菌龄为2d的菌丝7h,捕食性真菌D.flagrans产生原生质体数量最多且能够再生。这为下一步转化并标记和克隆捕食性相关基因奠定了重要基础。     

Impact of the nematophagous fungus Duddingtonia flagrans on Muellerius capillaris larvae in goat faeces

The small lungworm Muellerius capillaris is very prevalent in goats and causes production losses. Its control is particularly difficult. The nematophagous fungus Duddingtonia flagrans has been shown to be effective in trapping a large range of gastro-intestinal nematode larvae but its trapping activity against small lungworm remains to be assessed. The purpose of this work was firstly, to evaluate the ability of first-stage larvae of M. capillaris (L1) to induce trap formation in in vitro conditions and secondly, to determine the effect of D. flagrans on the L1 infectivity to snails. In experiments on agar, the presence of L1 failed to induce any D. flagrans traps whereas in the same conditions, gastro-intestinal third-stage larvae induced 44-135 traps/cm(2) depending on the species. Moreover, when the traps were pre-induced by Haemonchus contortus larvae, the L1 of M. capillaris were not trapped. For the in vivo trial, two goats naturally infected with M. capillaris received D. flagrans chlamydospores at the daily dose rate of 5x10(5) spores/kg BW for 8 days. Faeces were collected individually before, during and 11 days after spore administration. On each day of harvest, the initial larval output was determined. The remaining faeces were subjected to coproculture at 21 degrees C for 7 days. At the end of this period, L1 were collected and used to infect snails (30 snails per goat isolate each snail given 40 L1 by direct deposit of the larvae on the foot of the snail). These snails were artificially challenged in contrast to others that were exposed to natural infection by exposure to faeces carrying first-stage M. capillaris larvae. The natural infection used the same number of snails, i.e. 30 snails deposited on the faeces of each goat. After 3 weeks at room temperature, the infective larvae present in the snail foot were counted. There was no difference in the survival of the L1 in faeces after coproculture whether the faeces contained D. flagrans or not. The infectivity of the extracted larvae from the two goats before and after fungal administration was the same. The number of infective larvae per snail obtained after "natural" infection showed variations that were not related to the presence of D. flagrans mycelium in faeces. These trials clearly indicate that D. flagrans was unable to trap or to alter the infectivity of M. capillaris first-stage larvae and thus cannot be considered as a non-chemotherapeutic alternative approach to the control of the small lungworm in goats.     

Capability of the nematode-trapping fungus Duddingtonia flagrans to reduce infective larvae of gastrointestinal nematodes in goat feces in the southeastern United States: dose titration and dose time interval studies

Infection with gastrointestinal nematodes, particularly Haemonchus contortus, is a major constraint to goat production in the southeastern United States. Non-anthelmintic control alternatives are needed due to increasing resistance of these nematodes to available anthelmintics. Two studies were completed in Central Georgia in August 1999, and April–May 2000, using Spanish does naturally infected with Haemonchus contortus, Trichostongylus colubriformis, and Cooperia spp. to evaluate effectiveness of nematode-trapping fungi as a biological control agent. In the first experiment, five levels of Duddingtonia flagrans spores were mixed with a complete diet and fed once daily to the does (three per treatment) in metabolism crates. The treatment concentrations were (1) 5×10⁵, (2) 2.5×10⁵, (3) 10⁵, and (4) 5×10⁴ spores per kilogram body weight (BW), and (5) no spores. Fungal spores were fed for the first 7 days of the 14-day trial, and fecal samples were collected daily from individual animals for analysis of fecal egg count and establishment of fecal cultures. Efficacy of the fungus at reducing development of infective larvae (L3) in the fecal cultures was evaluated. The mean reduction in L3 from day 2 of the treatment period until the day after treatment stopped (days 2–8) was 93.6, 80.2, 84.1, and 60.8% for animals given the highest to lowest spore doses, respectively. Within 3–6 days after termination of fungal spore feedings, reduction in L3 development was no longer apparent in any of the treated animals. In a second experiment, effectiveness of 2.5×10⁵ spores of D. flagrans per kilogram BW fed to does every day, every second day, and every third day was evaluated. Reduction in L3 development by daily feeding was less in the second experiment than in the first experiment. Daily fungal spore feeding provided more consistent larval reduction than intermittant feeding (every second or third day). When fed daily under controlled conditions, D. flagrans was effective in significantly reducing development of L3 and appears to be an effective tool for biocontrol of parasitic nematodes in goats.     

A technique for the quantification of Duddingtonia flagrans chlamydospores in sheep faeces

Previous observations showed that Duddingtonia flagrans chlamydospores were visualized in McMaster chambers containing faeces of treated sheep. This trial explored the McMaster technique as a tool to quantify chlamydospores in sheep faeces. A range of individual chlamydospore doses (from 19.5 x 10(6) to 177.5 x 10(6)) were offered orally to nine lambs for 7 consecutive days. A faecal sample (5 g) was daily obtained from the rectum of each animal (from days 1 to 13) to perform the McMaster technique using a sugar flotation fluid with 1.27 g/mL density. Each chlamydospore counted in the McMaster chamber was considered as 50 chlamydospores per g of faeces (CPG). The results confirmed that the estimated CPG was associated with the daily dose offered to the animals (r(2)=0.90; P<0.001). Furthermore, the total chlamydospore dose received by each animal was strongly associated to the total quantity of CPG obtained from the bulk faeces (TCtot) (r(2)=0.96; P<0.0001). Quantification of CPG can be used as a helpful tool to determine the number of chlamydospores reaching the faeces in orally dosed animals. This could be used to evaluate the efficacy of D. flagrans for the control of gastrointestinal nematode larvae in sheep faeces.     

Efficacy of the nematode-trapping fungus Duddingtonia flagrans against three species of gastro-intestinal nematodes in laboratory faecal cultures from sheep and goats

The ability of the nematode-killing fungus Duddingtonia flagrans to reduce number of infective larvae of three species of gastro-intestinal parasitic nematodes developing in dung was investigated in both goats and sheep. Groups of lambs and kids (12-20 weeks old) were given mono-specific infections of Haemonchus contortus, Ostertagia (Teladorsagia) circumcincta or Trichostrongylus colubriformis. Following patency of the infections (t1) faecal samples were collected for determination of faecal nematode egg count (FEC) and culture of parasite larvae. Groups of animals were then dosed on 2 consecutive days with one of the two dose rates of the fungus (250,000 or 500,000 spores/kg liveweight). One (t2) and 5 (t3) days after the second dose of fungus samples were again collected for FEC and culture. The number of larvae recovered from the faecal cultures at t1 and t3 were used as controls to assess the efficacy of the experimental treatment at t2. Average efficacy was 78% with group means ranging from 40 to 93%. Dose rate of fungus appeared to influence efficacy against O. circumcincta but not against H. contortus or T. colubriformis. Overall, there were no differences in the efficacy of the fungus against any of the parasite species or in either host animal. The results of this trial indicate the potential use of this fungus as a broad spectrum anti-parasite agent for use in both goats and sheep.     

Efficacy of the nematophagous fungus Duddingtonia flagrans in reducing equine cyathostome larvae on pasture in south Louisiana

The effectiveness of Duddingtonia flagrans in reducing the free living third stage larvae (L(3)) of equine cyathostomes on pasture when fed to horses has been demonstrated in cold temperate climates. The objective of this experiment was to assess the efficacy of D. flagrans against equine cyathostomes in the subtropical environment of southern Louisiana. Fecal pats were prepared by mixing feces obtained from a parasite-free horse fed D. flagrans at a dose of approximately 2 x 10(6) spores kg(-1), with feces containing cyathostome eggs from a parasitized horse. Control pats contained feces from a parasite-free horse mixed with feces containing cyathostome eggs. The fecal pats were placed on pasture in six replicates at 4-week intervals from March 1997 until January 1998. Comparison of recoveries of L(3) from non-treated control pats in the field with non-treated coprocultures maintained in the laboratory indicated that L(3) survival on pasture was reduced during the months of May, June, July, August and September. The efficacy of the fungus was determined by L(3) recovery from grass surrounding the fecal pats of treated and control groups. D. flagrans significantly reduced L(3) during the months of April, May, and October 1997 to January 1998 (range 66-99% reduction, p=0.0001), and for the year as a whole (p=0.0001).     

Absence of obvious short-term impact of the nematode-trapping fungus Duddingtonia flagrans on survival and growth of the earthworm Aporrectodea longa

The nematode-trapping fungus Duddingtonia flagrans may be used in biological control of parasitic nematode larvae in faeces of domestic host animals after feeding the hosts with fungal chlamydospores. In this experiment a possible undesirable fungal impact on earthworms, of the species Aporrectodea longa, was investigated. As earthworms eat animal faeces, D. flagrans may come into contact with earthworms both in their alimentary tract and on their body surface. However during the experimental period of 20 days, when earthworms were living in soil and eating cattle faeces that were heavily infested with viable chlamydospores of D. flagrans there were no indications of internal or external mycosis among the earthworms.