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.     

Biological control of field infections of nematode parasites of young sheep with Duddingtonia flagrans and effects of spore intake on efficacy

A field study was undertaken to determine the effects of feeding Duddingtonia flagrans to young Merino sheep on pasture. A total of 60 mixed sex lambs 4-5 months old were divided into six even groups on the basis of liveweight. On Monday to Friday, each week for 6 months, three groups were offered barley grains on which D. flagrans had been cultured while the other three groups remained untreated. Every 4 weeks liveweights were recorded and faecal samples collected for nematode egg count estimation. Feeding D. flagrans reduced faecal egg counts and tended to improve liveweight gains, but considerable differences were observed between groups within treatment. These differences are thought to result from variations between the groups in consumption of the treated barley with the "best" consumers showing the greater effects of treatment.     

Biological control of goat gastrointestinal helminthiasis by Duddingtonia flagrans in a semi-arid region of the northeastern Brazil

The aim of this study was to test a pellet formulation in a sodium alginate matrix of Duddingtonia flagrans in the biological control of goat gastrointestinal helminths kept in a native pasture in a semi-arid region of Paraíba state, northeastern Brazil. An area of 2.4 ha was divided into three paddocks, where groups of seven goats ware formed. Each group received the following treatments during the months of March to August 2011: D. flagrans group, received 3g of pellets containing D. flagrans (AC001) for each 10 kg/l.w., twice a week; Moxidectin 0.2% group, received 0.2mg/kg of Moxidectin 0.2% orally, every 30 days; Control group, received 3g of pellets without fungi per 10 kg/l.w., twice a week. Each month, a tracer goat was placed in each group for 30 days and then sacrificed and necropsied. The D. flagrans group showed a greater reduction in EPG, increased weight gain, higher rates of packed cell volume and lower parasitic load burden in the tracer goats compared to Moxidectin 0.2% and Control groups. D. flagrans was efficient in controlling goat gastrointestinal helminthiasis in a semi-arid region of northeastern Brazil.     

The potential of nematophagous fungi to control the free-living stages of nematode parasites of sheep: feeding and block studies with Duddingtonia flagrans.

A series of feeding trials was conducted with penned sheep harboring Trichostrongylus colubriformis infections. They were offered barley grains supporting the growth of the nematophagous fungus Duddingtonia flagrans. It was shown that as little as 5g of grain/sheep per day was sufficient to virtually eliminate larval numbers from faecal culture. This effect persisted for the time that the fungal grains were fed, and for up to 2 days following cessation of feeding this material. Macerated fungal grains were also incorporated into a range of feed block formulations. In all these, D. flagrans was found to survive the manufacturing process and resulted in significant reductions in larval numbers in faecal cultures set up during the feeding period to sheep. This was observed even for sheep that showed only modest and irregular block consumption. These studies demonstrate that supplementary feeding or block administration offer potential deployment options for D. flagrans as a means of biological control of nematode parasites of livestock.     

Trapping efficacy of Duddingtonia flagrans against Haemonchus contortus at temperatures existing at lambing in Australia

The aim of this study was to determine the trapping efficacy of Duddingtonia flagrans against Haemonchus contortus at the temperature ranges experienced around lambing in the major sheep producing regions of Australia. Faeces were collected from Merino wethers, maintained in an animal house and which had received either D. flagrans chlamydospores for a 6-day period (DF) or not (NIL). Faeces were incubated at one of four daily temperature regimens which were composed of hourly steps to provide 6-19 degrees C, 9-25 degrees C, 14-34 degrees C and 14-39 degrees C to mimic normal diurnal air temperature variation. Enumeration of the number of preinfective and infective larvae that had migrated from or remained in faecal pellets was used to calculate percentage recovery and trapping efficacy of D. flagrans. Recovery of H. contortus larvae of both stages was significantly lower in DF faeces but the magnitude of the effect was considerably greater for infective larvae. Mean recovery of infective larvae from NIL and DF faeces was 10.6 and 0.4%, respectively, indicating a mean trapping efficacy of 96.4%. The lowest trapping efficacy (80.7%) was observed at 6-19 degrees C but total recovery of infective larvae, from DF faeces, was greatest at the two highest temperature regimens, although still less than 0.9%. The results of this study indicate that typical Australian lambing temperatures should not be a barrier to the use of D. flagrans as an effective biocontrol of H. contortus in Australia.     

Interaction between copper oxide wire particles and Duddingtonia flagrans in lambs

An experiment was completed to determine if copper oxide wire particles (COWP) had any effect on the activity of the nematode-trapping fungus Duddingtonia flagrans in growing lambs. COWP has been used recently as a dewormer in small ruminants because of nematode resistance to anthelmintics. D. flagrans has been used to control free-living stages of parasitic nematodes in livestock. Katahdin and Dorper lambs, 4 months of age, were administered no or 4 g COWP (n=24/dose) in early October 2003. Haemonchus contortus was the predominant gastrointestinal parasite during the trial, which was acquired naturally from pasture. Half the lambs from each COWP group were supplemented with corn/soybean meal with or without D. flagrans for 35 days. Fecal egg counts (FEC) and packed cell volume (PCV) were determined weekly between days 0 (day of COWP administration) and 35. Feces from lambs in each treatment group were pooled and three replicates per group were cultured for 14 days at room temperature. Larvae (L3) were identified and counted per gram of feces cultured. Treatment with COWP was effective in decreasing FEC, which remained low compared with FEC from lambs not treated with COWP. This led to an increase in PCV in these lambs (COWP x day, P<0.001). Number of larvae was decreased in feces from lambs treated with COWP and D. flagrans between days 14 and 35 compared to the other groups of lambs (COWP x D. flagrans x day, P<0.003). Percentage of larvae identified as H. contortus decreased in feces collected from lambs treated with COWP and D. flagrans between days 14 and 28 compared with other treatments (COWP x D. flagrans x day, P<0.05). Other trichostrongyles were present and remained less than 7% in feces collected from control lambs. There was no adverse effect of COWP on the ability of D. flagrans to trap residual larvae after COWP treatment. With fewer eggs being excreted due to the effect of copper on H. contortus, and the additional larval reducing effect exerted by the nematode destroying fungus D. flagrans, the expected result would be a much lower larval challenge on pasture when these two tools are used together in a sustainable control strategy.     

The effect of Duddingtonia flagrans on trichostrongyle infections of Saanen goats on pasture

Four groups of nine Saanen goat does with a naturally acquired mixed trichostrongylid infection were grazed on four paddocks. Two groups received a daily dose of Duddingtonia flagrans at the rate of 5 x 10(7) chlamydospores per animal per day for the 26-day grazing period. After a 19-day pasture resting period, 20 worm free 12-week-old tracer kids were introduced to the paddocks for 14 days prior to removal for worm burden analysis. Four groups of five does and four kids were drenched then turned out onto the paddocks and faecal egg count (FEC) monitored. The FEC between groups was comparable throughout the initial grazing period. There were significant reductions in number of Teladorsagia circumcincta (54.8%, P=0.004) and Haemonchus contortus (85.0%, P=0.02) worms recovered from tracer animals. FEC of animals subsequently grazing pasture were significantly reduced (P=0.036) with reductions of 44% observed 4 weeks post-turnout. No significant difference was observed after 6 weeks grazing. This trial has demonstrated the potential of D. flagrans to reduce larval numbers on pasture grazed by goats under New Zealand conditions.     

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).     

Field studies on the biological control of nematode parasites of sheep in the tropics, using the microfungus Duddingtonia flagrans

Long-term field studies were conducted on two government managed small ruminant research farms, located in different geo-climatic regions and approximately 300 km separate from each other, on Peninsula Malaysia. The Infoternak trial (48 weeks) and the Chalok trial (43 weeks) each compared nematode parasite control in separately managed groups of young sheep, either short-term rotationally grazed around a suite of 10 paddocks in addition to receiving a daily supplement of Duddingtonia flagrans spores (Fungus Group); or similar groups of sheep being rotationally grazed alone (Control Group). The prevailing weather conditions at Infoternak farm were of below average rainfall conditions for the most of the trial. As a consequence, only very low worm infections (almost exclusively Haemonchus contortus) were acquired by the 17 sets of tracer lambs that grazed sequentially with the experimental lambs. However on all except 2 occasions in the early part of the trial, the mean tracer worm burdens were significantly lower (P < 0.05) and the experimental lambs grew significantly better (P = 0.054) in the Fungus Group. Rainfall at Chalok farm during the course of the trial was also below average. As a consequence infectivity of pastures was assumed to be relatively low based on faecal egg counts (epg) of the experimental sheep, which following an anthelmintic treatment prior to allocation, remained very low in both treatment groups. Faecal egg counts of undosed replacement lambs in the latter half of the Chalok study, showed a progressive increase in the Control Group to levels exceeding 3000 epg, whereas the Fungus Group remained static at approximately 500 epg. These results show that the deployment of the nematophagous fungus, D. flagrans, can improve the level of parasite control of sheep in the tropics above that which can be achieved by the short-term rotational grazing strategy alone.     

Disintegration of dung pats from cattle treated with the ivermectin anthelmintic bolus, or the biocontrol agent Duddingtonia flagrans

An experiment was performed during the grazing seasons of 1998, 1999 and 2000 to study the influence of the antiparasitic drug ivermectin and the nematophagous fungus Duddingtonia flagrans on cattle dung disintegration. The faeces originated from groups of animals that were part of a separate grazing experiment where different control strategies for nematode parasite infections were investigated. Each group consisted of 10 first-season grazing cattle that were either untreated, treated with the ivermectin sustained-release bolus, or fed chlamydospores of D. flagrans. Faeces were collected monthly on 4 occasions and out of pooled faeces from each group, 4 artificial 1 kg dung pats were prepared and deposited on nylon mesh on an enclosed pasture and protected from birds. The position of the new set of pats was repeated throughout the 3 years of the study. Each year, the dung pats were weighed 4, 6, 8 and 10 weeks after deposition and immediately afterwards replaced to their initial positions. Results showed that there was no difference in faecal pat disintegration between groups. However, the time-lag between deposition and complete disintegration of the faeces varied significantly between deposition occasions. Dung pats disappeared within 2 weeks (visual observation) when subjected to heavy rainfall early after deposition, whereas an extended dry period coincided with faeces still remaining 12 months after deposition.     

Administration of Duddingtonia flagrans chlamydospores to goats to control gastro-intestinal nematodes: dose trials

The ability of the nematophagous fungus Duddingtonia flagrans to reduce the number of infective nematode larvae in coproculture was investigated in goats using different doses of chlamydospores (0, 1.25 x 10(5), 2.5 x 10(5), 5 x 10(5) chlamydospores/kg BW/day) given by oral administration or by voluntary consumption in feed during natural or experimental infections with nematodes. The kinetics of excretion of D. flagrans chlamydospores in the faeces was also determined using a dose of 5 x 10(5) chlamydospores/kg BW/day for five days. For all the trials, the faecal nematode egg outputs were determined by a modified McMaster method and standard coprocultures were set up (14 days, 25 degrees C) to determine the number of larvae emerging from culture in fungus treated and control faeces. When chlamydospores were orally administered, the number of larvae were reduced by 50 to 97% when compared to control cultures. No difference in the level of larval emergence from the culture was seen for experimental or natural infections at the different chlamydospore dose rates. In contrast, when chlamydospores were distributed in the feed, a dose-dependent relationship was observed 10 days after the start of administration, the larval development being 2.0%, 14.0% and 86.9% for 5 x 10(5), 2.5 x 10(5) and 0 spores/kg BW/day, respectively. In addition, the kinetic study showed that the larval emergence from coproculture in the fungus group was statistically lower than in the control group from the second day of administration of the chlamydospores and remained lower until the second day after the last administration (p < 0.05). The results indicate that, for goats in farm conditions, a minimum daily dose of 5 x 10(5) chlamydospores/kg BW must be used to ensure a high treatment efficacy and that daily administration is preferable for maintenance of efficacy over time.     

Evaluation of biological control of sheep parasites using Duddingtonia flagrans under commercial farming conditions on the island of Gotland, Sweden

Field trials, conducted over 3 consecutive years, were aimed at assessing farmer opinions of the practicality and effectiveness of using Duddingtonia flagrans to control nematode parasites in their flocks on the Swedish island of Gotland. These trials were also monitored by intensive parasitological investigation. On Gotland, lambing occurs in spring, and around mid-summer (late June), ewes and lambs are moved to saved pastures due to pasture deterioration caused by dry conditions. Weaned lambs are then returned to original lambing pastures in early autumn for finishing. One farm (B) was used for 2001-2003 and a second farm (N) was also used in 2002 and 2003. On each farm, two flocks (each of 20 ewes + twin lambs) were managed separately, namely: fungus group which received a daily supplement + fungal spores from lambing until the summer move (6 weeks) and: control group which received supplement only. For Farm B, the numbers of lambs that were marketed prior to the end of the grazing season, were 13, 18, 19 for the fungus treatment whereas corresponding numbers for the control treatment were 8, 16 and 11 for years 2001, 2002 and 2003, respectively. Final weights of the remaining lambs at the end of each year were also consistently heavier, and the numbers of lambs retained for finishing during winter were less, on the fungus treatment compared with the control treatment. On Farm N, similar results were recorded, with more lambs marketed earlier in the fungus group (25 and 19) compared with the control (19 and 15) in 2002 and 2003, respectively. The weights of the remaining lambs at the end of the trial in 2003 showed a 4.5 kg weight gain advantage of the fungus group compared to the controls. Tracer tests during autumn 2001 on Farm B, showed that Teladorsagia circumcincta plus Trichostrongylus spp. levels were significantly less on the fungus treatment (P=0.018). The summer/autumn of 2002 was one of the driest on record for Gotland. This resulted in very low levels of infective larval availability. But on both farms, T. circumcincta numbers were less on the fungus than on the control paddocks (P=0.048 on Farm B). In 2003 very low numbers of infective larvae were recorded in the autumn tracers for both treatments on both farms. Both farmer co-operators were encouraged with these results and consider that biological control of nematode parasites in their flocks, using D. flagrans, is of practical value.     

Efficiency of Duddingtonia flagrans against Trichostrongyle infections of sheep on mountain pastures

The control of sheep nematode parasites in extensive mountain/transhumant management systems using the nematophagous fungus Duddingtonia flagrans was assessed in this study. Two groups of Churra Tensina ewes were allowed to graze for 8 weeks in autumn on two separate paddocks of infected pasture near their winter sheds in the valley. At lambing, ewes and their twin lambs were turned out into the same paddocks for the following 12 weeks. One group of ewes received a daily dose of 5 x 10(5) chlamydospores of Duddingtonia flagrans/kg live weight per day both in autumn and in spring, while the other group was used as a non-treated control. Daily dosing of grazing ewes with the fungus D. flagrans had a clear effect on reducing autumn pasture contamination. This had a subsequent effect on the over-wintering larvae population that was confirmed by a 20% lower worm burden of tracer lambs kept in early spring on the paddock previously grazed by fungus treated ewes. In spring, pasture contamination was also significantly reduced in the paddock grazed by fungi-treated ewes and their lambs showed a 61% lower worm burden and a better performance than the control lambs. Results herein show that fungal spores fed to sheep at critical times with regard to the epidemiology of parasite infection, can have a significant effect on the infective larvae present on pasture, which could further improve lambs performance. This novel approach to parasite control would be of interest amongst both organic and conventional sheep farmers operating in mountain regions.     

Effect of different times of administration of the nematophagous fungus Duddingtonia flagrans on the transmission of ovine parasitic nematodes on pasture--a plot study

Investigations were made into the timing of administration of Duddingtonia flagrans as a biological control agent against ovine parasitic nematodes including stongylid and Nematodirus spp. Faeces from 3-4 months old male lambs were deposited onto pasture plots that had never been grazed by sheep. The trial was conducted over two consecutive years (1998 and 1999). For both years, the following three plot types were involved: Sim plots had faeces containing nematode eggs and Duddingtonia flagrans spores deposited simultaneously; Post plots had faeces containing nematode eggs followed 2 weeks later by faeces containing D. flagrans spores alone; Control plots had faeces containing only nematode eggs; Prior plots (included in 1999) had faeces containing D. flagrans spores alone followed 2 weeks later by faeces containing nematode eggs. In each year, two deposition periods were involved: July and August in 1998 and June and July in 1999. During the first year pasture samples were collected at 2, 4, 6, 8 and 12 weeks after initial deposition. In 1999, additional samples were collected at 10, 16 and 20 weeks. Larvae were extracted from the pasture samples and counts performed to estimate the number and species of infective third-stage (L(3), larvae) present. The number of third-stage strongylid larvae on pasture was significantly lower on Sim plots compared to the remaining plot types for both years at all deposition times (P<0.001). This was also the case for the number of Nematodirus infective larvae in August deposition plots in 1998 (P<0. 02). There was no significant difference between treatments in both deposition times in 1999 and July deposition plots in 1998 for the Nematodirus data. These results suggest that D. flagrans, if deposited at the same time as parasite eggs prevents transmission of third-stage larvae from the faecal deposit onto pasture, including occasionally Nematodirus species, but does not have an effect on third-stage parasitic nematode larvae in the surrounding soil.     

Giardia duodenalis and Cryptosporidium parvum infections in adult goats and their implications for neonatal kids

During the kidding season between January and April 2003, 10 farms were selected and divided into two groups of five. The farms in group A had had serious diarrhoeal illness and losses in neonatal kids the previous year, and there were Cryptosporidium parvum infections in kids associated with diarrhoea during the survey. On the farms in group B, there was no history of diarrhoeal disease the previous year and neither C parvum oocysts nor diarrhoea were detected in neonatal kids during the survey. Faecal samples were collected once from 10 adult goats aged between one and seven years on each farm. To assess more accurately the pattern of output of oocysts of C parvum and cysts of Giardia duodenalis by periparturient adult goats, one farm was selected from each group, faecal samples were collected weekly before and after kidding from 12 goats on the farm in group A and from 10 goats on the farm in group B. There was no significant difference in the prevalence of G duodenalis cysts between the group A farms (14 per cent) and the group B farms (12 per cent), and the numbers of cysts excreted ranged from 143 to 400 cysts per gram of faeces (cpg) on the group A farms and 72 to 334 cpg on the group B farms. There was a significant difference (P=0.03) in the prevalence of C parvum oocysts at the group level between the group A farms (20 per cent) and the group B farms (6 per cent). All the adult goats excreted cysts and oocysts at some date around the kidding period; the number of animals excreting cysts of G duodenalis or oocysts of C parvum increased when they gave birth, and seven to 10 times more cysts and oocysts were shed in the three weeks around kidding than in the period more than three weeks from kidding (P<0.001).     

The impact of daily Duddingtonia flagrans application to lactating ewes on gastrointestinal nematodes infections in their lambs in the Netherlands

Two experiments were performed in 2002 and 2003 to evaluate the effect of biological control of gastrointestinal nematodes in sheep through the daily feeding of 500,000 chlamydospores of Duddingtonia flagrans/kg bodyweight to lactating ewes during the first 9 weeks with their young lambs on pasture. In both experiments four groups of eight ewes and their April-borne lambs were used. They were turned out on four separate plots (plots A) at the beginning of May, moved to similar separate plots after 3 (plots B) and 6 weeks (plots C), respectively, and weaning occurred after 9 weeks. In both experiments, two groups were fed spores daily while the two other groups served as controls. The effect of D. flagrans application was evaluated through faecal egg counts of ewes and lambs, the yield of faecal cultures in ewes, pasture larval counts and worm counts of lambs and tracer lambs. The results demonstrated no effect of D. flagrans application during the first 5 (2002) or 4 (2003) weeks. Subsequently, fungus application strongly reduced the yield in faecal cultures of the ewes. This was, however, not reflected in the pasture larval counts, but lower worm burdens were observed in tracer lambs of 'treated' plots C in 2002 than on those of 'control' plots. In 2003 worm burdens in 'treated' lambs returned to plots B were lower than those of 'control' lambs and a tendency for the same was observed for plots C. However, in all groups, lambs and tracer lambs developed severe haemonchosis.     

Ability of the fungus Duddingtonia flagrans to adapt to the cyathostomin egg-output by spreading chlamydospores

The analysis of the capability of the nematode trapping-fungus Duddingtonia flagrans to adapt to the cyathostomin egg-output in horses was evaluated. Fecal samples from 196 pasturing autochthonous Pura Raza Galega horses were collected from the rectum and then divided according to the egg-output into three groups: ≤ 300, 310-800 and >800 eggs per gram feces. Four doses of chlamydospores (0.1, 0.2, 0.4 and 0.8 × 10(6)/100g feces) were directly spread onto fecal pats on the ground, remaining one without treatment as control. Fecal pats confirmed the presence of gastrointestinal nematode larvae belonging to strongylid cyathostomins (Cyathostomum and Gyalocephalus spp). An overall 94% (95% CI 91, 97) percentage of reduction was obtained, and an increase in the activity of the trapping-fungi simultaneously to the rising in the number of cyathostomin eggs and larvae in the coprocultures was detected. A significantly highest reduction of the cyathostomin L3 in the coprocultures with more than 800 EPG was found, which indicates that Df trapping activity is larvae nematode density-dependant. The present research showed the high biological activity of D. flagrans against nematode larvae can adjust to the cyathostomin egg-output, and underlines its efficacy as a practical method for the control of these parasites in grazing horses.     

Efficiency of feeding Duddingtonia flagrans chlamydospores to grazing ewes on reducing availability of parasitic nematode larvae on pasture

Gastrointestinal nematodes are of concern in sheep production because of production and economic losses. Control of these nematodes is primarily based on the use of anthelmintic treatment and pasture management. The almost exclusive use of anthelmintic treatment has resulted in development of anthelmintic resistance which has led to the need for other parasite control options to be explored. The blood sucking abomasal parasitic nematode Haemonchus contortus causes severe losses in small ruminant production in the warm, humid sub-tropic and tropics. This study evaluated the effectiveness of a nematode trapping fungus, Duddingtonia flagrans, in reducing availability of parasitic nematode larvae, specifically H. contortus, on pasture. Chlamydospores of D. flagrans were mixed with a supplement feed which was fed daily to a group of crossbred ewes for the duration of the summer grazing season. A control group was fed the same supplement feed without chlamydospores. A reduction in infective larval numbers was observed in fecal cultures of the fungus-fed group. Herbage samples from the pasture grazed by the fungus-fed group also showed a reduction in infective larvae. There were no significant (P > 0.05) differences in overall fecal egg count, packed cell volume or animal weight between fungus-fed and control groups. Tracer animals were placed on the study pastures at the end of the study to assess pasture infectivity. Although tracer animals were only two per group, those that grazed with the fungus-fed group had substantially reduced (96.8%) nematode burdens as compared to those from the control group pasture. Results demonstrated that the fungus did have activity against nematode larvae in the feces which reduced pasture infectivity and subsequently nematode burdens in tracer animals. This study showed that D. flagrans, fed daily to grazing ewes, was an effective biological control agent in reducing a predominantly H. contortus larval population on pasture.     

Effect of nematophagous fungus Duddingtonia flagrans and energy supplementation on the epidemiology of naturally infected kids

Gastrointestinal (GI) nematode infection is a major constraint for grazing livestock production. The increasing prevalence and severity of anthelmintic-resistant nematodes in many parts of the world has led to a search for non-chemical control options. Under experimental conditions, the nematophagous fungus Duddingtonia flagrans is emerging as an alternative to chemotherapy for the control of GI nematode infection in biological production systems. Also, recent information points to the role of energy nutrition to increase the immune response against GI nematode infection. In this study the effect of D. flagrans and energy supplementation on the epidemiology of GI nematode infections is explored on grazing kids. Four groups of 10, 4-month old goats were turned out on infected pasture in the early spring and allocated to four separate paddocks where they were rotationally grazed for 16 weeks. One of these groups (F) received 0.5 x 10(6) D. flagrans spores/kg BW/d. Another group (S) was supplemented with 100 g barley grain per day. A third group (F+S) received both nematophagous fungi and barley supplement treatments simultaneously while the fourth group (C) was used as a non-treated control. Both nematophagous fungi and barley supplement had a significant effect (P<0.01) on reducing pasture infectivity, faecal egg excretion and worm burdens at slaughter that was particularly evident for Trichostrongylus colubriformis. The combination of both treatments showed a synergistic effect on the control of gastrointestinal nematode infections. At slaughter, the average total post-mortem worm count of the F+S group was reduced by 65% compared with the non-treated control. The results herein show that D. flagrans can act as an efficient biological control agent against kid GI nematode infections on pasture, which could further improve carcass characteristics. While small amounts of energy supplement can also reduce kid infection, the effect of D. flagrans as a biological control agent appeared clearly enhanced both in magnitude and duration by energy supplementation. This has clear implications for grazing animals and provides an efficient method for the practical control of parasitic nematodes in biological production systems.     

Nematophagous fungi as a biological control agent for nematode parasites of small ruminants in Malaysia: a special emphasis on Duddingtonia flagrans

Approximately 2,800 fresh dung samples from animals, mainly ruminant livestock, were screened for the presence of nematophagous fungi in Malaysia. Arthrobotrys spp. was noted on numerous occasions, but only one isolate of Duddingtonia flagrans was made. For the purposes of producing sufficient quantities of this fungus for feeding trials in sheep, various, commonly available, cheap plant materials were tested as possible growth substrates. This showed that cereal grains (wheat, millet and rice) were the best media for fungal growth. Pen feeding trials were carried out using sheep, both naturally and experimentally infected with nematode parasites (predominantely Haemonchus contortus), to test the efficiency of D. flagrans when administered either in a grain supplement, or incorporated into a feed block. These showed that the fungus survived gut passage in sheep and that dose rates of approximately 1 x 10(6) D. flagrans spores / animal / day, reduced the percentage of infective larvae developing in faecal cultures by more than 90%. These results indicate that using D. flagrans as a biological control agent of nematode parasites, is a promising alternative to nematode parasite control of small ruminants in Malaysia, where anthelmintic resistance is now a major problem.