[Show abstract][Hide abstract] ABSTRACT: After oral administration of ewes during mid gestation with 2000 freshly prepared sporulated oocysts of T. gondii isolate M4, abortions occurred between days 7 and 11 in 91.6% of pregnant and infected ewes. Afterwards, a further infection was carried out at late gestation in another group of sheep with 500 sporulated oocysts. Abortions happened again between days 9 and 11 post infection (pi) in 58.3% of the infected ewes. Classically, abortions in natural and experimental ovine toxoplasmosis usually occur one month after infection. Few experimental studies have reported the so-called acute phase abortions as early as 7 to 14 days after oral inoculation of oocysts, and pyrexia was proposed to be responsible for abortion, although the underline mechanism was not elucidated. In the present study, all placentas analysed from ewes suffering acute phase abortions showed infarcts and thrombosis in the caruncullar villi of the placentomes and ischemic lesions (periventricular leukomalacia) in the brain of some foetuses. The parasite was identified by PCR in samples from some placentomes of only one sheep, and no antigen was detected by immunohistochemical labelling. These findings suggest that the vascular lesions found in the placenta, and the consequent hypoxic damage to the foetus, could be associated to the occurrence of acute phase abortions. Although the pathogenesis of these lesions remains to be determined, the infectious dose or virulence of the isolate may play a role in their development.
Veterinary Research 01/2014; 45(1):9. · 3.38 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The effects of heather (composed primarily of Calluna vulgaris with a smaller content of Erica umbellata and Erica cinerea) consumption on the establishment of incoming infective larvae (experiment 1, preventive treatment) and an adult worm population (experiment 2, curative treatment) were investigated in Cashmere goats experimentally infected with Trichostrongylus colubriformis. In experiment 1, 12 castrated male goats were divided into two groups: heather-supplemented vs. non-supplemented animals. After 2 weeks of adaptation to the diet, all goats were experimentally infected per os with 6,000 T. colubriformis third-stage larvae. Three weeks post-infection, the goats were slaughtered, and worm counts as well as female worm fecundity and development were determined. Heather consumption was associated with a close to significant (P = 0.092) reduction (mean 14 %) in larvae establishment. No effect on fecundity was observed, but the length of female worms in supplemented goats was greater (P < 0.001). In experiment 2, 15 non-lactating does were experimentally infected with 6,000 T. colubriformis third-stage larvae. At 6 weeks post-infection, three groups were established: control, heather-supplemented and heather-supplemented with polyethylene glycol. Individual faecal nematode egg output was measured twice weekly to assess gastrointestinal nematode egg excretion. The goats were slaughtered 5 weeks after heather administration (11 weeks post-infection), and worm counts as well as female worm fecundity and development were subsequently determined. Heather administration was associated with a significant (P < 0.001) decrease (between 47 and 66 % compared with control group) in egg excretion from 45 to 76 days post-infection. Although worm counts and female fecundity were lower in supplemented goats, no significant differences were observed. Overall, the results showed a reduction in T. colubriformis larvae establishment and a decrease in nematode egg excretion when heather was administered in experimentally infected goats. The heather plus polyethylene glycol treatment reduced nematode egg excretion levels at the same proportion as heather, thereby suggesting that the threshold of tannins required for an anthelmintic effect is most likely quite low.
Parasitology Research 11/2013; 113(2). · 2.33 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study was carried out to evaluate the in vitro effects of different heather species on Trichostrongylus colubriformis eggs, larvae and adult worms, and obtain scientific evidence to attribute these effects to the action of their phenolic compounds and/or tannins. Total phenolic extracts of three heather species (Calluna vulgaris, Erica cinerea, and Erica umbellata) and an equal mixture of these three extracts were tested in vitro in the three development stages of T. colubriformis using an egg hatching assay (EHA), larval exsheathment inhibition assay (LEIA), and adult motility inhibition assay (AMIA). The egg hatching rate was measured after incubation with heather extracts for 48h at 25°C. Infective third-stage larvae (L3) were incubated for 3h at 25°C with heather extracts. The evolution of artificial exsheathment over time was measured with repeated observations at 20-min intervals for 60min. Adult worms were obtained from one donor goat and incubated with the extracts at 37°C for 5 days in 48-multiwell plates. Worm motility was measured at 0, 19, 24, 43, 48, 67, 72, 96 and 115h after the beginning of the experiment. The extracts were tested at concentrations of 75, 150, 300, 600 and 1200μg/ml. All extracts significantly (P<0.001) inhibited egg hatching and the effect was dose dependent. All extracts inhibited or delayed the exsheathment of T. colubriformis L3, and the effect was dose dependent for C. vulgaris. Incubation with heather extracts induced a reduction in adult worm motility compared to control, although significant (P<0.05) differences were only found at the highest concentrations. Additional studies showed that purified tannins of the same heather species disturbed T. colubriformis larval exsheathment. All these results confirm the anthelmintic properties of heather against T. colubriformis, and suggest that not only tannins but also some other phenolic compounds might be involved.
[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to evaluate the in vitro effects of heather (Ericaceae) phenolic extracts on the abomasal nematodes Teladorsagia circumcincta and Haemonchus contortus. Extracts of three heather species (Calluna vulgaris, Erica cinerea, Erica umbellata and a balanced mixture of all three) were tested in vitro on different development stages of T. circumcincta (eggs, infective larvae and adult worms) and H. contortus (eggs and infective larvae) using an egg hatching assay (EHA), a larval exsheathment inhibition assay (LEIA) and an adult motility inhibition assay (AMIA). The egg hatching rate was measured after incubation with heather extracts for 48h at 25°C. Ensheathed infective larvae were incubated for 3h at 20°C with heather extracts. Artificial exsheathment was induced in vitro by adding hypochloride solution to the larval suspension. The progress of exsheathment over time was measured by repeated observations at 10-min (T. circumcincta) and 20-min (H. contortus) intervals for 60min. Adult T. circumcincta worms were obtained from two donor goats and incubated with the extracts at 37°C for 3 days in 48-well multiwell plates. Worm motility was measured at 0, 19, 24, 43, 48, 67 and 72h. The extracts were tested at concentrations of 75, 150, 300, 600 and 1200μg/mL. Incubation with E. cinerea, E. umbellata and mixed heather extracts had a significant (P<0.01) dose-dependent effect on T. circumcincta egg hatching. H. contortus egg hatching was significantly (P<0.01) inhibited only by the E. cinerea extract. All extracts had a significant (P<0.01) dose-dependent effect on the exsheathment of T. circumcincta and H. contortus infective larvae. The incubation with all heather extracts induced a reduction in adult T. circumcincta motility compared to the control, although significant (P<0.05) differences were only found at the highest concentration (1200μg/mL). The effect of the mixed extract was significant at all concentrations and significant effects were also observed for C. vulgaris and E. umbellata at 600μg/mL. These results show anthelmintic properties of heather phenolic extracts against T. circumcincta and H. contort, thus confirming observations from previous in vivo studies.
[Show abstract][Hide abstract] ABSTRACT: This study was performed in Cashmere goats that were experimentally infected with Teladorsagia circumcincta to investigate the effects of heather consumption on the establishment of incoming infective larvae (experiment 1) and on an adult nematode population (experiment 2). In experiment 1, 24 non-lactating goats were divided into 2 groups: heather-supplemented vs. non-supplemented. After 2 weeks of adaptation to the diet, all of the goats were experimentally infected with 6000 infective larvae of T. circumcincta. Twelve animals (6 controls and 6 supplemented with heather) were slaughtered at 6 days and at 3 weeks post-infection (pi). After slaughter, the worms were counted and the female worm fecundity and development were determined. Heather consumption was associated with a significant reduction in larval establishment at 6 days (P=0.033) and at 3 weeks (P=0.041) pi. No differences in worm counts between the slaughter times were found. In the goats slaughtered at 3 weeks pi, the number of eggs in utero and length of the female worms were significantly (P<0.001) lower than those of control group. In experiment 2, 24 non-lactating goats were experimentally infected with 10,000 T. circumcincta infective larvae daily for 5 consecutive days (total infection of 50,000 larvae). After 3 weeks, 2 groups were established: control and heather-supplemented. The faecal egg output of each animal was measured at 2-days interval during the experimental period. The goats were slaughtered after 3 weeks of heather administration for parasitological studies. Heather administration was associated with a significant decrease in egg excretion between 25 and 29 days pi. The worm counts were similar in both groups, but the female length and fecundity were significantly (P<0.001) lower in supplemented goats. These results show that heather consumption reduces the establishment of T. circumcincta larvae in goats and the development and fecundity of female adult parasites.
[Show abstract][Hide abstract] ABSTRACT: Some bioactive plants such as tannin-containing heather can reduce parasitic infections by gastrointestinal nematodes, enhancing goat performance. Thus, goats could select to feed on heather despite its low nutritive value to maintain a better health status. The aim of this work was to evaluate the effects of heather supplementation on diet selection, nutrient intake, and gastrointestinal nematode infections in grazing goats. Four 0.5 ha-paddocks with Agrostis capillaris-dominated grasslands were established in western Asturias (northern Spain). Twelve Cashmere goats with their kids were allocated in each paddock from April to November. In two of the paddocks, goats were offered freshly cut heather (mostly Calluna vulgaris) every 3 days, whereas no heather was supplied in the other two. Diet selection (pasture-heather) and daily dry matter intake (DMI) of goats were estimated in two periods (June and October) using alkane markers. Samples of pasture and heather were analysed for crude protein (CP), neutral and acid detergent fibre (NDF, ADF) and acid detergent lignin (ADL), and their daily intakes calculated. Faecal samples were collected monthly for faecal nematode egg count (FEC). In June, mean heather percentage in the diet of supplemented goats was 21%. Total DMI per metabolic body weight was not affected by heather supplementation (mean 64 g DM kg BW−0.75 d−1), indicating a total replacement of pasture by heather. As a consequence, CP intake was lower while ADF and ADL intakes were higher (P < 0.05) in supplemented than in pasture-fed goats. In October, heather percentage in the diet of supplemented goats was 35%, and total DMI was lower than in June in both supplemented and non-supplemented goats (31 and 27 g DM kg BW−0.75 d−1, respectively). Thus, goats again substituted pasture for heather to a large extent (68%). ADF and ADL intakes were higher (P < 0.01) in supplemented goats, with no differences for CP intake, partly due to the lower CP contents in the autumn pasture. FEC increased less (P < 0.05) across the grazing season in supplemented goats (46% reduction level in relation to non-supplemented goats). In spite of the nutritionally poorer intake, heathersupplemented goats showed more favourable BW changes. In conclusion, goats chose to feed on tannin-containing heather instead of grazing only on more nutritious pasture. Goats sacrificed nutrient intake in the interests of health, which ultimately improved their productive responses.
[Show abstract][Hide abstract] ABSTRACT: It is widely accepted that the type of vegetation, i.e. the botanical composition and the subsequent nutritive quality, greatly affects nutrient intake and performance of goats. However, goat performance may be also affected via health status because of the role of some plant secondary compounds on parasitic infections and/or toxicity. The objective of this study is to compare the performance and parasitic status of non-lactating goats during summer-autumn grazing (after weaning their kids) on three common vegetation types in the northwest of the Iberian Peninsula: perennial ryegrass (Lolium perenne)-white clover (Trifolium repens) improved pastures (P), heather (Ericaceae)-dominated shrublands (heathlands strictly speaking, H), and gorse (Ulex gallii)-dominated shrublands (G). Cashmere goats (4 per paddock in 2010, 6 per paddock in 2011) grazed four paddocks of 0.5 ha (P) or 0.6 ha (H and G) per vegetation type from late July to late October. Goats were monthly weighed and their body condition (BC) scored. Parasitic infection by gastrointestinal nematodes was assessed by faecal egg counts (FEC). In both years, body weight (BW) and BC changes were more favourable in P and H than in G. Goats gained BW during the whole experimental grazing season in P and H (4.2 and 37.5 g/day in P, 10.8 and 28.3 g/day in H, in 2010 and 2011, respectively), whereas goats lost BW in G (-35.0 and -5.2 g/day in 2010 and 2011, respectively; P < 0.01). BC changes were 0.00, -0.04 and -0.45 in 2010 (P < 0.05), and 0.15, 0.10 and -0.00 in 2011 (P = 0.16), for P, H and G, respectively. FEC were more reduced in H than in P and G, accounting for 741, 5372 and 2128 eggs/g in October 2010 (P < 0.001), and 641, 2581 and 2503 eggs/g in October 2011 (P < 0.01) in H, P and G, respectively. These results support previous evidence on the anthelmintic effect of heather, presumably owing to its tannin content. Therefore, the lower nutritive value of H vegetation (even compared with G regarding the protein contents) is offset by its positive effect on goat health, achieving similar performances to those observed in good quality pastures. Goats could be managed on heathlands between weaning and mating with no apparent detrimental effects on subsequent reproductive performance. This allows a more flexible grazing management, e.g. preserving the improved pastures for more demanding animals, reducing feeding costs and getting more sustainable meat production systems.
[Show abstract][Hide abstract] ABSTRACT: In the last decade, numerous studies have been carried out to evaluate the potential anthelmintic benefit of the consumption of bioactive plants in small ruminants, in order to reduce the dependence on conventional chemotherapy and supporting a sustainable control of gastrointestinal (GI) parasitism. This review summarizes the anthelmintic and nutritional effects of heather (shrub species belonging to the Ericaceae family, such as Erica spp. or Calluna vulgaris) supplementation in grazing goats naturally infected by GI nematodes. The experiments were carried out in a mountain area in north-western Spain where shrubby heather-gorse vegetation is dominant. Some plots were established, in which the vegetation had been improved by soil ploughed and dressing and sowing perennial ryegrass (Lolium perenne) and white clover (Trifolium repens), and removing any heather that was present. Cashmere goats reared outdoors under pasture conditions were used in the experiments. The trials compared the response to GI nematode infections, animal performance and nutrition in goats supplemented or not with heather. Interactions between heather availability and other alternative methods to control GI nematode infections based on grazing management (stocking rate) or nutrition (energy supply) as well as the potential adaptation of the rumen microbiota to the consumption of tannins, were also studied. The results suggest that (i) heather supplementation in grazing goats significantly reduces the level of GI nematode egg excretion, (ii) the faecal nematode egg count reduction could be associated with a decrease in worm fertility and/or reduction in the establishment of incoming third-stage larvae, (iii) consumption of heather is associated with an apparent greater resilience of goats to GI nematode infections, and (iv) the amount of tannins consumed by the goats supplemented with heather does not seem to be associated to anti-nutritional effects which eventually resulted in a better animal performance in the animals incorporating these shrubs in their diet. Practical application of this knowledge in temperate areas would support the management of plots integrating improved pastures with high nutritive value (ryegrass-white clover) with natural vegetation communities.
Small Ruminant Research 03/2012; 103(1):60-68. · 1.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Previous field studies have supported the absence of a nutritional cost outweighing the beneficial anthelmintic effect of supplementing the diet of grazing goats with tannin-containing heather. In order to fur-ther research in this regard, an experiment was conducted indoors with 18 does artificially infected with Trichostrongylus colubriformis. The goats were offered lucerne hay for 6 weeks and then assigned to 3 treat-ments (diets): lucerne hay (L), 70% lucerne hay + 30% heather containing 64 g of tannic acid equivalents/kg DM (LH), and LH + polyethylene glycol (35 g PEG/animal and day; LH+PEG). Rumen fluid was obtained from each animal after 10 (period 1) and 36 (period 2) days, and afterwards total faecal output was collected for 5 days to assess gastrointestinal nematode egg excretion, and apparent digestibilities of DM and CP. Total daily faecal egg excretion was reduced in does consuming heather (491,216 for L vs 234,311 and 194,356 for LH+PEG and LH; P<0.05). Volatile fatty acid concentrations were greater in those animals (115 vs 102 vs 84 for LH, LH+PEG and L, respectively, P<0.05) but the use of PEG increased DM and CP digestibilities (P<0.05). In vitro gas production results suggest an adaptation of the rumen microbiota in goats supple-mented with heather that was not reflected in differences between digestibility coefficients in periods 1 and 2. The fact that LH+PEG significantly improved the apparent digestibilities of DM (6%) and CP (13%) when compared to LH, but with both reducing egg excretion in the same proportion, might suggest that the thresh-old of tannins requested to obtain anthelmintic effects is probably quite low.
Options Méditerranéennes, Series A (Séminaires Méditerranéens). 09/2011; 99:321-327.
[Show abstract][Hide abstract] ABSTRACT: This work aimed to evaluate the effects of tannin-containing heather (Calluna vulgaris, Erica spp.) and energy (oats, Avena sativa) supplementation, combined or not, on feed intake, gastrointestinal nematode infections and performance of goats grazing mountain grasslands. Two successive experiments were established across one grazing season on four paddocks. The first (late April to early August, Period 1) involved two treatments, i.e., supplementation with heather (+H) vs. non-supplementation (−H), each randomly allocated to two paddocks. The second (mid-August to mid-November, Period 2) consisted on four treatments in a 2×2 factorial design, i.e., supplementation with heather and oats (+H+O), only heather (+H−O), only oats (−H+O), and no supplementation (−H−O). Results from Period 1 indicated that faecal nematode egg counts (FEC) were lower in +H goats (50% less in August), achieving more favourable live weight (LW) and body condition changes than −H goats. Total dry matter intake (DMI) in June was similar between treatments, with heather accounting for 0.21 of +H goat diets. Kids FEC and LW gains were not affected by heather supplementation. In Period 2, both heather and oat supplementation reduced FEC (45 and 61%, respectively) and improved goat performance, without an interaction between both factors. Total DMI in October was higher in +H+O compared to other treatments (48 vs. 30 g DM kg LW−0.75 d−1; P < 0.01). Rumen ammonia concentration was lower (P < 0.001) in +H than in −H goats, and in +O than in −O goats, whereas that of volatile fatty acids (VFA) was not affected by treatments, though the molar proportions of some VFA were modified. It is concluded that the combination of both supplements (tannins and energy) contributes to reduce gastrointestinal nematode parasitism and increases goat performance, allowing a lower dependence on conventional chemotherapy.
Small Ruminant Research 07/2010; 91(2-3):186-192. · 1.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study, performed on 62 adult dry cashmere goats grazing upland perennial ryegrass–white clover pastures and naturally infected with gastrointestinal nematodes, was to investigate the effects of stocking rate (SR: 24 vs. 38 goats ha-1) and tannin-containing heather supplementation (H: Calluna vulgaris [L.] Hull, Erica spp.) vs. nonsupplementation on parasite burden, fecal egg counts (FEC), and live weight (LW) changes. Goats were randomly assigned to four treatments in a 2 X 2 factorial arrangement and grazed continuously from May to October. Six goats per treatment were slaughtered at the end of the grazing period, and adult worms in the abomasum and small and large intestines of each animal were recovered, counted, and identified. FEC was affected by SR (P<0.01) but not by H. However, the SR X H interaction was significant (P<0.05). FEC increased (P<0.001) along the grazing season in all treatments, and the SR X time interaction was significant (P<0.001). In general, mean total worm counts in abomasum and small intestine tended to be higher under high SR, although the differences were only significant (P<0.01) in Trichostrongylus spp. counts. In goats managed under the high SR, the mean of total Teladorsagia circumcincta counts was lower (P<0.01) in supplemented animals, but no differences were recorded for Trichostrongylus spp., Chabertia ovina, Oesophagostomum columbianum, and Trichuris ovis. The goats gained more LW (P<0.001) under low SR and when they were heather-supplemented. No significant SR X H interaction was found for LW change. In conclusion, high stocking rate increases the infectivity risk of pasture and the supplementation of grazing goats with heather contributing to improve animals’ performance. Notwithstanding, the effect of heather availability on nematode FEC reduction could be highly dependent on the climatic conditions.
[Show abstract][Hide abstract] ABSTRACT: To test the hypothesis that the beneficial anthelmintic effect of consuming moderate amounts of tannins may not always be accompanied by anti-nutritional effects in goats, two experiments were conducted. In the first, 48 Cashmere goats were randomly assigned to two treatments: supplementation with tannin-containing heather (6.4% total tannins) and non-supplementation. All goats grazed continuously from May to September under farm conditions in a mountainous area of northern Spain. The mean percentage of heather incorporated into the diet of the supplemented animals was 29.1%. Supplementation reduced the mean number of nematode eggs in faeces (P < 0.001) and the goat mortality rate (P < 0.05). The rumen ammonia concentration was markedly reduced in the goats receiving the heather supplement (160 v. 209 mg/l; P < 0.01), while volatile fatty acid (VFA) concentrations were significantly greater (63.0 v. 53.6 mmol total VFA/l; P < 0.05). The heather-supplemented goats also showed a lower loss of live weight (P < 0.01) and body condition score (P < 0.001). In the second experiment, batch cultures of rumen microorganisms with rumen fluid from nine goats whose diet included 29% heather - or not, were used to incubate three substrates (pasture, pasture + heather and pasture + heather + polyethylene glycol) to investigate in vitro ruminal fermentation. Differences (P < 0.01) among substrates were observed in terms of dry matter disappearance (DMD), in vitro true substrate digestibility (ivTSD), gas production and ammonia concentration, the greatest values always associated with the pasture substrate. Cultures involving rumen inoculum derived from goats receiving the heather-containing diet showed slightly lower DMD (46.9 v. 48.5 g/100 g; P < 0.05), ivTSD (64.6 v. 65.9 g/100 g; P < 0.10) and gas production (105 v. 118 ml/g; P < 0.001) values, but much greater total VFA concentrations (48.5 v. 39.3 mmol/l; P < 0.05), and suggest that the efficiency of ruminal fermentation in these animals was probably improved. Together, the results support the absence of a clear nutritional cost counteracting the beneficial anthelmintic effect of supplementing the diet of grazing goats with tannin-containing heather.