A Survey of Control Strategies for Equine Small Strongyles in Lithuania.

Anthelmintic resistance (AR) in equine cyathostomins is being reported all over the world. In Lithuania, however, the last study on this subject was published more than fifteen years ago, thus little is known about the current situation. The aim of this study was to determine the factors that may associated with the development of AR on equine studs in Lithuania. A questionnaire containing seven open-ended and nine closed multiple-choice questions about worm control strategies, use of anthelmintic substances and stable management practices was posted to 71 randomly selected horse establishments in Lithuania. Replies were obtained from a total of 59 stables, representing 83 % of officially established stud farms in Lithuania. The results showed that more than 80 % of these establishments performed pasture management practices such as excrement removal from stables and pasture, 56 % mowed their pasture, 31 % practised mixed or rotational grazing with other species, and 97 % of the horses were routinely dewormed. Macrocyclic lactones (ML) (58 %, n=33) were the most commonly used drugs, followed by benzimidazoles (BZ) (24 %, n=14) and tetrahydropyrimidines (THP) (19 %, n=10). The majority of farms (60 %) treated horses four times per year and 68 % estimated the weight of the horses by eye before treatment. About 36 % of respondents had heard of faecal egg counts (FEC), but only 17 % used the test and as few as 9 % had tested their herds for AR with faecal egg count reduction tests (FECRT). The results demonstrate that there is scope for improving routines for worm control in many horse establishments in Lithuania. In order to increase knowledge and reduce the risk of the spread of AR, diagnostic methods should be adopted in a collaboration between stud farms and veterinary practitioners.

Initial assessment of the economic burden of major parasitic helminth infections to the ruminant livestock industry in Europe.

We report a European wide assessment of the economic burden of gastrointestinal nematodes, Fasciola hepatica (common liver fluke) and Dictyocaulus viviparus (bovine lungworm) infections to the ruminant livestock industry. The economic impact of these parasitic helminth infections was estimated by a deterministic spreadsheet model as a function of the proportion of the ruminant population exposed to grazing, the infection frequency and intensity, the effect of the infection on animal productivity and mortality and anthelmintic treatment costs. In addition, we estimated the costs of anthelmintic resistant nematode infections and collected information on public research budgets addressing helminth infections in ruminant livestock. The epidemiologic and economic input data were collected from international databases and via expert opinion of the Working Group members of the European Co-operation in Science and Technology (COST) action COMbatting Anthelmintic Resistance in ruminants (COMBAR). In order to reflect the effects of uncertainty in the input data, low and high cost estimates were obtained by varying uncertain input data arbitrarily in both directions by 20 %. The combined annual cost [low estimate-high estimate] of the three helminth infections in 18 participating countries was estimated at € 1.8 billion [€ 1.0-2.7 billion]. Eighty-one percent of this cost was due to lost production and 19 % was attributed to treatment costs. The cost of gastrointestinal nematode infections with resistance against macrocyclic lactones was estimated to be € 38 million [€ 11-87 million] annually. The annual estimated costs of helminth infections per sector were € 941 million [€ 488 - 1442 million] in dairy cattle, € 423 million [€ 205-663 million] in beef cattle, € 151million [€ 90-213 million] in dairy sheep, € 206 million [€ 132-248 million] in meat sheep and € 86 million [€ 67-107 million] in dairy goats. Important data gaps were present in all phases of the calculations which lead to large uncertainties around the estimates. Accessibility of more granular animal population datasets at EU level, deeper knowledge of the effects of infection on production, levels of infection and livestock grazing exposure across Europe would make the largest contribution to improved burden assessments. The known current public investment in research on helminth control was 0.15 % of the estimated annual costs for the considered parasitic diseases. Our data suggest that the costs of enzootic helminth infections which usually occur at high prevalence annually in ruminants, are similar or higher than reported costs of epizootic diseases. Our data can support decision making in research and policy to mitigate the negative impacts of helminth infections and anthelmintic resistance in Europe, and provide a baseline against which to measure future changes.

Comparison of the cardiovascular and respiratory effects and sevoflurane requirement in dogs premedicated with two doses of medetomidine and butorphanol undergoing surgical sterilization.

The aim of this study was to compare the cardiovascular and respiratory effects and sevoflurane requirement in dogs premedicated with two doses of medetomidine and butorphanol undergoing surgical sterilization. The dogs were randomly assigned to two different groups: group 1 received a lower dose of medetomidine (0.014 mg/kg) and butorphanol (0.14 mg/kg) and group 2 received a higher dose of medetomidine (0.024 mg/kg) and butorphanol (0.24 mg/kg). Anesthesia was induced with intravenous propofol and maintained with sevoflurane 2% in pure oxygen. Heart rate, SpO2, respiratory rate, EtCO2, esophageal temperature, systolic and diastolic arterial blood pressures, capillary refill time, reflexes (palpebral, pedal), jaw tone, and eye position (straight, down) were assessed. Anesthesia was monitored continuously by an anesthesiologist, and variables were recorded every 5 min. During general anesthesia, the median sevoflurane (SVO) concentrations and the median HR were significantly lower in group 2 than group 1 (p<0.05). The median HR was 96.3 (85.8-100.8) in group 1, whereas in group 2 it was 77.0 (67.5-84.6) (p<0.05). It might be concluded that the higher dose of medetomidine and butorphanol allows the use of a lower sevoflurane concentration during routine surgical treatments and ensures stable work of the cardiovascular and respiratory systems.

A comparison of modifications of the McMaster method for the enumeration of Ascaris suum eggs in pig faecal samples.

The comparative efficacies of seven published McMaster method modifications for faecal egg counting were evaluated on pig faecal samples containing Ascaris suum eggs. Comparisons were made as to the number of samples found to be positive by each of the methods, the total egg counts per gram (EPG) of faeces, the variations in EPG obtained in the samples examined, and the ease of use of each of the methods. Each method was evaluated after the examination of 30 samples of faeces. The positive samples were identified by counting A. suum eggs in one, two and three sections of newly designed McMaster chamber. In the present study compared methods were reported by: I-Henriksen and Aagaard [Henriksen, S.A., Aagaard, K.A., 1976. A simple flotation and McMaster method. Nord. Vet. Med. 28, 392-397]; II-Kassai [Kassai, T., 1999. Veterinary Helminthology. Butterworth-Heinemann, Oxford, 260 pp.]; III and IV-Urquhart et al. [Urquhart, G.M., Armour, J., Duncan, J.L., Dunn, A.M., Jennings, F.W., 1996. Veterinary Parasitology, 2nd ed. Blackwell Science Ltd., Oxford, UK, 307 pp.] (centrifugation and non-centrifugation methods); V and VI-Grønvold [Grønvold, J., 1991. Laboratory diagnoses of helminths common routine methods used in Denmark. In: Nansen, P., Grønvold, J., Bjørn, H. (Eds.), Seminars on Parasitic Problems in Farm Animals Related to Fodder Production and Management. The Estonian Academy of Sciences, Tartu, Estonia, pp. 47-48] (salt solution, and salt and glucose solution); VII-Thienpont et al. [Thienpont, D., Rochette, F., Vanparijs, O.F.J., 1986. Diagnosing Helminthiasis by Coprological Examination. Coprological Examination, 2nd ed. Janssen Research Foundation, Beerse, Belgium, 205 pp.]. The number of positive samples by examining single section ranged from 98.9% (method I), to 51.1% (method VII). Only with methods I and II, there was a 100% positivity in two out of three of the chambers examined, and FEC obtained using these methods were significantly (p<0.01) higher comparing to remaining methods. Mean FEC varied between 243 EPG (method I) and 82 EPG (method IV). Examination of all three chambers resulted in four methods (I, II, V and VI) having 100% sensitivity, while method VII had the lowest 83.3% sensitivity. Mean FEC in this case varied between 239 EPG (method I) and 81 EPG (method IV). Based on the mean FEC for two chambers, an efficiency coefficient (EF) was calculated and equated to 1 for the highest egg count (method I) and 0.87, 0.57, 0.34, 0.53, 0.49 and 0.50 for remaining methods (II-VII), respectively. Efficiency coefficients make it possible not only to recalculate and unify results of faeces examination obtained by any method but also to interpret coproscopical examinations by other authors. Method VII was the easiest and quickest but least sensitive, and method I the most complex but most sensitive. Examining two or three sections of the McMaster chamber resulted in increased sensitivity for all methods.

Faecal egg output and herbage contamination with infective larvae of species of Ostertagia and Oesophagostomum from naturally infected farmed sika deer Cervus nippon in Lithuania.

Faecal egg outputs and subsequent herbage larval contamination with third stage larvae (L3) of Ostertagia spp. and Oesophagostomum spp. from a herd of naturally infected sika deer Cervus nippon were examined in the same pasture in 2001/2002 in Lithuania. Sika deer were infected with Ostertagia circumcincta, O. kolchida, O. spiculoptera, Oesophagostomum radiatum, O. columbianum and O. venulosum. Faecal egg output in adult deer peaked in the spring during the periparturient period and also in late August, compared with a peak in egg output in calves during September to November. Herbage contamination with L3 of Ostertagia spp. peaked in June but larvae were not present on pastures from the end of September. Hence the highest risk of infection was in early born calves grazed on pastures in July. Infective larvae of Oesophagostomum spp. did not survive during the winter, but the nematodes were reintroduced onto the pastures by adult deer in the spring.

Prevalence and epidemiological features of ovine enzootic abortion in Lithuania.

The aim of performed study was to determine the level of enzootic abortion (EA) in sheep breeding farms in different districts of Lithuania, to determine differences in clinical signs and infection frequency between various age groups, and to evaluate the sensitivity and specificity of complement fixation test for antibodies detection and indirect immunofluorescence for antigen detection in sheep chlamydiosis. The clinical, serological and immunological tests in sheep farms were performed in 2004 and 2005. Comparing different age groups of sheep revealed that the lowest number of infected sheep was registered in animals younger than 18 months (23.1%, antibodies titre 3.191 log2, P<0.05) and highest in animals aged 18 to 24 months (53.8%, antibodies titre 4.224 log2, P<0.001). In sheep aged more than 3 years, titre of antibodies was significantly reduced. The majority of infected sheep which aborted (86.4%) was registered in 18-24 month age group. Furthermore, in sheep which aborted the infection level was 2.5-fold higher as compared to sheep which didn't abort. Analysis of smears from patological material by indirect FAT revealed that 54.5% of animals were positive to Chlamydophila abortus infection. The highest prevalence of chlamydia (66.7%) was registered in placentas of sheep which aborted.

The effect of inulin on new and on patent infections of Trichuris suis in growing pigs.

The objective of this experiment was to investigate the potential influence of inulin on the establishment of new and patent infections of Trichuris suis in growing pigs. Two experimental diets were formulated based on barley flour with either added insoluble fibre from oat husk (Diet 1) or a pure inulin (16%) supplementation (Diet 2). Twenty-eight 10-week-old pigs were divided randomly into 4 groups (Groups 1-4) each of 7 pigs. After 3 weeks adaptation to the experimental diets all pigs were infected with a single dose of 2000 infective T. suis eggs. Group 1 was fed Diet 1 until 7 weeks post-infection (p.i.) and Group 3 until 9 weeks p.i., Group 2 was fed Diet 2 until 7 weeks p.i., Group 4 was fed Diet 1 until week 7 p.i. and was switched-over from Diet 1 to Diet 2 until week 9 p.i. Seven weeks p.i. pigs in Groups 1 and 2 were slaughtered, and pigs in Groups 3 and 4 were slaughtered at 9 weeks p.i. Trichuris suis worm burdens were determined for all pigs. Inulin-fed pigs (Group 2) exhibited an 87% reduction in EPG, compared to the pigs on standard diet (Group 1) (P < 0.0001). The number of worms recovered at week 7 p.i. from pigs on the inulin diet (Group 2) was significantly reduced by 71%, compared to the pigs on standard diet (Group 1) (P < 0.01). At week 9, worm recovery in pigs on the inulin diet switch protocol (Group 4) was reduced by 47% compared to the control pigs in Group 3 (P < 0.01). Further, the inulin-fed pigs exhibited a significant reduction in female worm fecundity and worm large intestine location was more distal compared to those from pigs on standard diet. These results demonstrate that inclusion of the highly degradable fructose polymer inulin in the diet leads to significant reductions in T. suis establishment, egg excretion, and female worm fecundity and can be used as a treatment for patent infections.

The influence of dietary carbohydrates on experimental infection with Trichuris suis in pigs.

Two experiments (Exps 1 and 2) were carried out to study the effect of dietary carbohydrates on the establishment of Trichuris suis in pigs. Two experimental diets based on barley flour were used; Diet 1 was supplemented with non-fermentable carbohydrates from oat hull meal, while Diet 2 was supplemented with fermentable carbohydrates from sugar beet fibre and inulin. In Exp. 1, thirty-two pigs were allocated randomly into 4 groups. Two groups were fed Diet 1 and 2 groups were fed Diet 2. Pigs from one of each diet group were inoculated with 2000 infective T. suis eggs each and the other two groups were uninfected controls. All pigs were slaughtered 8 weeks post-inoculation (p.i.). In Exp. 2, twenty-four pigs were allocated randomly into 2 groups and fed Diet 1 or Diet 2, respectively. All the pigs were inoculated with 2000 infective T. suis eggs. Six pigs from each group were slaughtered 8 weeks p.i. and the remaining 6 pigs from each group were slaughtered 12 weeks p.i. Infections were followed by faecal egg counts and worm burdens were assessed at necropsy. Pigs fed Diet 2 had lower egg counts in both experiments; in Exp. 2 the difference was significant (P<0.05). No differences were found in worm burdens 8 weeks p.i. in both experiments, however, worms from pigs on Diet 2 were significantly shorter (P<0.0001). Pigs fed Diet 2 and slaughtered 12 weeks p.i. had significantly lower worm counts (P<0.01) compared to pigs fed Diet 1. The results indicate that fermentable carbohydrates do not affect the establishment of T. suis in naïve pigs, but result in earlier expulsion and reduced growth of the established worms. Thus, diets with highly fermentable carbohydrates may be used in the control of T. suis.

Evaluation of different laboratory methods for diagnosis of pig chlamydiosis in Lithuania.

Pig chlamydiosis is antrophozoonosis caused by Chlamydophila abortus. Chlamydias (C type) are widely found in nature and can infect humans, domestic and wild mammals, and 139 types of birds. The peculiar feature of chlamydias is the tropism to different tissues, organs and organisms. In 2502 pig blood sera tests from Lithuanian farms, anti-chlamydia complement binding (CB) antibodies were detected in 192 cases (7.7%). Serological tests showed the following (C type) chlamydia bearing regions: 22.0% Mazeikiai district, 17.2%--Kaisiadorys district, 13.5%--Panevezys district, 12.3%--Vilkaviskis district. Rare incidence of the disease was found in Siauliai district 1,2% and Klaipeda district 2.5% farms. The highest antibody titers in blood serum tests were found in Joint Stock Company (JSC) "Krekenava" and "Vejine", i.e. 1:128 and 1:64, respectively. The following methods for the study of pig chlamydiosis were used and comparatively evaluated: complement binding reaction (CBR), direct immunofluorescence (DIF), imunoenzyme assay (IEA), indirect immunofluorescense (IIF), micro immunofluorescense (MIF), polymerase chain reaction (PCR) and cell culture (CC) test. PCR method was found to be more sensitive and reliable compared to imunoenzyme assay, but the latter is more economic especially for screaning. In pigs with the clinically expressed symptoms, 108 pigs infected with chlamydia were detected. CB assay revealed the infection rate from 3.4% to 7.9% in piglets, sows and boars. The highest level of chlamydia infection was detected in fatteners (17.6%). Seroepizootic study of pig chlamydiosis revealed the different infection rate in the animals investigated. The highest chlamydia infection risk is in winter (10.4%) and the lowest--in summer (2.8%).

Effects of short-chain fatty acids and lactic acids on survival of Oesophagostomum dentatum in pigs.

The direct influence of intracaecal infusion of short-chain fatty acids (SCFA) and lactic acids (LA) on already established Oesophagostomum dentatum infection in cannulated pigs was investigated. We tested the hypothesis that the previously discovered anti-parasitic effect of inulin is mediated through its metabolic products SCFA and LA by infusing into cannulated pigs these compounds in amounts approximating to those produced in the pigs large intestine and caecum during the metabolism of inulin. The experiment comprised of 18 pigs--2 groups of 9 pigs in each. The normal diet used in the experiment was based on barley flour with insoluble fibre from oat husk with added soybean meal, vitamins and minerals. After 2 weeks of adaptation to the diet all the pigs were inoculated with 6,000 infective larvae of O. dentatum. Six weeks later, surgery on all pigs was performed to install cannulas into caeci. At 7 weeks post-infection (p.i.) the SCFA and LA infusion was initiated in Group 1 (experimental) pigs; at the same time pigs in Group 2 (controls) were infused with saline. At week 10 p.i., all pigs were killed and their worm burdens determined. SCFA and LA infused pigs exhibited markedly reduced fecal egg counts and worm recoveries (98 and 92% reduction, respectively, compared to saline controls). The results from this study demonstrate that SCFA and LA have a significant negative influence on established O. dentatum infection in growing pigs. The results also show that the type of dietary carbohydrates fed and its intestinal degradation can yield metabolic by products that profoundly influence helminth survival.

Effects of Oesophagostomum dentatum and dietary carbohydrates on morphology of the large intestine of pigs.

The effects of Oesophagostomum dentatum infection and dietary carbohydrates on the morphology and epithelial cell proliferation in the gastrointestinal tract of pigs were investigated experimentally. Thirty-two worm-free pigs (n=32) from a specific pathogen-free farm were randomly divided into four groups (A-D), of eight animals each. Pigs in groups A (control) and B (infected) were fed Diet 1, and pigs in groups C (control) and D (infected) were fed Diet 2. The two diets were formulated: Diet 1 (%) contained barley flour, oat husk meal plus soya bean meal (55:21:24) and Diet 2 (%) contained barley flour, inulin and sugar beet fibre (SBF) (80.1:7:12.9) plus soya bean meal (3:1) to contain carbohydrates from inulin and sugar beet fibre (SBF) that were readily fermentable in the large intestine. The two infected pig groups (16 pigs total) were inoculated with 6000 infective larvae of O. dentatum and all pigs, including the controls, were slaughtered 12 weeks p.i. The combination of O. dentatum infection and highly fermentable dietary carbohydrates affected the mucosal architecture, the epithelial cell proliferation and mucin secretion of the large intestine. Infection had a significant influence on the crypt volume, height and density, and on muscularis externa at the proximal and middle colon. The changes in the affected gut sections were proportional to the number of worms present. However, these parameters appeared unaffected by those diets alone. In pigs without infection non-digestible dietary carbohydrates significantly influenced the tissue weight of colon.

The effect of inulin and sugar beet fibre on oesophagostomum dentatum infection in pigs.

The present study was designed to assess the role of inulin and sugar beet fibres (SBF) on adult O. dentatum in growing pigs. Four experimental diets were formulated based on barley flour with added insoluble fibre from oat husk (Diet 1), a pure carbohydrate source inulin (Diet 2), soluble fibre from sugar beet fibre (SBF) with a high proportion of soluble fibre components (Diet 3) or inulin plus SBF (Diet 4). Thirty-two 10-week-old pigs were divided randomly into 4 groups each of 8 pigs. After 3 weeks adaptation on Diet 1 all pigs were infected with a single dose of 6000 L8 O. dentatum. At week 7 p.i. one group was switched to Diet 2, another group to Diet 3 and another group to Diet 4. The remaining 8 pigs continued on Diet 1 until the end of the experiment and served as controls. At week 13, all pigs were necropsied and their worm burdens determined. The worm recoveries from the pigs on the inulin supplemented diet (Diet 2) were reduced by 97% compared to the controls (Diet 1). Further, the inulin-fed pigs exhibited markedly reduced faecal egg counts. The pigs on inulin plus SBF diet (Diet 4) and on SBF diet (Diet 3) had 86% and 70% adult worm reductions compared with the controls, respectively. The results from this study indicate that highly degradable and rapidly fermentable carbohydrates such as dietary inulin have a profound deworming effect on O. dentatum infection.

The effect of dietary carbohydrates with different digestibility on the populations of Oesophagostomum dentatum in the intestinal tract of pigs.

An experiment was undertaken to study the effect of dietary carbohydrates with different digestibility on the populations of Oesophagostomum dentatum in the intestinal tract of pigs. Sixty-four worm-free pigs from a specific pathogen-free farm were randomly divided into 8 equal groups. The animals in 4 groups were assigned to a diet with partially undegradable carbohydrates (diet 1), while the pigs in the 4 remaining groups were given a diet with fermentable carbohydrates (diet 2). Diet 1 was comprised of barley flour, oat husk meal, soybean meal, vitamins and minerals and diet 2 of barley flour, inulin and sugar beet fibre, soybean meal, vitamins and minerals. The pigs in 6 of the groups (n = 48) were inoculated with 6,000 infective larvae of O. dentatum. To determine O. dentatum populations at the early stage of infection, 16 pigs were slaughtered 3 weeks p.i., while the remaining 4 groups continued on the diets for a further 9 weeks after which they were slaughtered. In a diet cross-over experiment 6 weeks after inoculation, 8 pigs changed from diet 1 to diet 2 (diet 1 > diet 2), and 8 pigs from diet 2 to diet 1 (diet 2 > diet 1). The results showed that partially undegradable carbohydrates provided favourable conditions not only for parasite establishment and sustainability, but also for already established O. dentatum infection while, in contrast, the diet composed of highly degradable carbohydrates decreased worm establishment, size and female fecundity. The implications for pastured pigs or pigs fed different complex carbohydrate diets is discussed.

Ecological influences on transmission rates of Ascaris suum to pigs on pastures.

A study was conducted to determine the distribution and transmission rate of Ascaris suum eggs and Oesophagostomum dentatum larvae in a pasture/pig house facility, which during the preceding summer was contaminated with helminth eggs by infected pigs. In May, four groups of 10 helminth naïve tracer pigs were exposed to fenced sections of the facility for 7 days and necropsied for parasite recovery 9-10 days later (trial 1). The highest rate of A. suum transmission (201 eggs per day) occurred in the pig house (A). On the pasture, egg transmission decreased with the distance from the house: 8 eggs per day in the feeding/dunging area (B); 1 egg per day on the nearest pasture (C); <1 egg per day on the distant pasture (D). Only a few O. dentatum infections were detected, indicating a poor ability of the infective larvae to overwinter. Soil analyses revealed that the highest percentage (5.8%) of embryonated A. suum eggs were in the house (A). Subsequently, the facility was recontaminated with A. suum eggs by infected pigs. A replicate trial 2 was conducted in the following May. A major finding was the complete reversal of egg distribution between the 2 years (trials 1 and 2). In contrast to previous results, the highest rates of transmission (569 and 480 eggs per day) occurred in pasture sections C and D, and the lowest transmission rates (192 and 64 eggs per day) were associated with the feeding/dunging sections and the house (B and A). Soil analyses again supported the tracer pig results, as the pasture sections had the highest concentrations of embryonated eggs. Detailed soil analysis also revealed a non-random, aggregated egg distribution pattern. The different results of the two trials may be due to the seasonal timing of egg deposition and tracer pig exposure. Many eggs deposited during the summer prior to trial 1 may have died rapidly due to high temperatures and dessication, especially when they were not protected by the house, while deposition in the autumn may have favored egg survival through lower temperatures, more moisture, and greater sequestration of eggs in the soil by rain and earthworms. The latter eggs may, however, not have become embryonated until turnout the next year. The results demonstrate that yearly rotations may not be sufficient in the control of parasites with long-lived eggs, such as A. suum, and that a pasture rotation scheme must include all areas, including housing.

The effect of increasing levels of insoluble dietary fibre on the establishment and persistence of Oesophagostomum dentatum in pigs.

This investigation compared the effect of diets with increasing content of insoluble dietary fibre (DF) on the establishment and persistence of Oesophagostomum dentatum in growing pigs. Twenty-eight worm-free pigs, from a specific pathogen-free farm were randomly divided to four groups of seven animals. The animals were assigned to the following diets: diet A, barley flour plus protein mixture (70%:30%); diet B, barley flour, oat husk meal plus protein mixture (65%:7%:28%); diet C, barley flour, oat husk meal plus protein mixture (60%:14%:26%) and diet D, barley flour, oat husk meal plus protein mixture (55%:21%:24%). The diets were formulated to provide increasing content of DF but constant levels of digestible protein per feeding unit for pigs. All pigs were experimentally inoculated with 6,000 infective O. dentatum larvae and followed coprologically for 11 weeks post infection, whereafter they were slaughtered. The experimental diets influenced the mean transit time and the metabolism in the large intestine significantly. Diets C and D, with highest content of insoluble DF, provided favourable conditions for establishment of O. dentatum, but diets A and B led to a significant lower worm numbers and fecundity.

The impact of diets varying in carbohydrates resistant to endogenous enzymes and lignin on populations of Ascaris suum and Oesophagostomum dentatum in pigs.

The impact of diets varying in type and level of carbohydrates resistant to endogenous enzymes and lignin on the establishment and location of Ascaris suum and Oesophagostomum dentatum was investigated experimentally. Fifty worm-free pigs, from a specific pathogen-free farm were used. The animals were assigned randomly to 5 diets and infected with 600 infective A. suum eggs and 6000 infective larvae of O. dentatum per pig. The diets consisted of a traditional ground barley plus protein feed (diet A), commercial full-constituent pelleted feed (diet B), barley flour plus protein (diet C), barley flour, inulin (Raftiline ST, ORAFTI, Tienen, Belgium), sugar beet fibre plus protein (diet D), and barley flour, wheat bran, and protein (diet E). The faecal egg excretion was followed and the pigs were slaughtered at 8 weeks p.i. and samples taken from the small and large intestine. Intestinal contents were analysed for worm burdens, worm location and female worm fecundity along with the concentration of insoluble (chromic oxide) and soluble (polyethylene glycol-4000) markers, lignin, non-starch polysaccharides (NSP) and organic acids. In all diet groups A. suum worm burdens were low and comparable, whereas the O. dentatum worm burdens were significantly higher in pigs fed the diets with high levels of NSP and lignin (diets A and E) than in pigs fed diets B, C, and D. The present study suggests that a diet rich in lignin and insoluble NSP's provides favourable conditions for the establishment of O. dentatum in the large intestine of pigs while it is unlikely that the concentration of short-chain fatty acids and pH plays and major role.

The effect of fasting on Ascaris suum and Oesophagostomum spp. in growing pigs.

Experiments were conducted to study the possible influence of fasting on Ascaris suum and Oesophagostomum spp. In growing pigs. Forty young crossbred pigs naturally infected with A. suum and Oesophagostomum spp. were used. In one experiment 10 pigs were fasted and offered water ad libitum for 6 days, in another experiment for 10 days. Subsequently, these pigs, together with 10 non-fasted control pigs per experiment were slaughtered, and worm numbers, worm location, sex, developmental stage and female worm fecundity were determined. Pigs fasted for 10 but not for 6 days had decreased numbers of A. suum and Oesophagostomum spp. at slaughter vs controls, and worms were found in more distal locations in the gastrointestinal tract. Fasting for both 6 and 10 days significantly lowered the fecundity of both worm species.

The effect of two types of diet on populations of Ascaris suum and Oesophagostomum dentatum in experimentally infected pigs.

This investigation compared the effect of two common types of diet on worm burdens and faecal egg counts of pigs inoculated with Ascaris suum and Oesophagostomum dentatum. The diets were both considered nutritionally sufficient for pigs of this age, and gave high and comparable growth rates. Pigs were inoculated with both worm species at 14 weeks of age and slaughtered 3 or 12 weeks later. At 3 weeks, A. suum larvae were numerous in the small intestine of pigs fed ground barley plus protein supplement, but were not detected from pigs fed a commercial full-constituent pelleted feed. At 12 weeks, however, average adult worm burdens were low and similar in both groups. At both slaughter times, O. dentatum worm burdens were significantly higher in pigs fed barley plus protein than in pigs given commercial feed, particularly for female worms, and the commercial diet led to worms being located further along the large intestine, and to reduced worm fecundity. The chemical composition of large intestinal contents differed significantly between pigs fed the two diets.