In vitro larval migration and kinetics of exsheathment of Haemonchus contortus larvae exposed to four tropical tanniniferous plant extracts
Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carretera Mérida-Xmatkuil, Mérida, Yucatán, Mexico. Veterinary Parasitology
(Impact Factor: 2.46).
05/2008; 153(3-4):313-9. DOI: 10.1016/j.vetpar.2008.01.042
As for some temperate forage, some tropical tanniniferous plants (TTP) from browsing might represent an alternative to chemical anthelmintic. The anthelmintic effect of four TTP (Acacia pennatula, Lysiloma latisiliquum, Piscidia piscipula, Leucaena leucocephala) on Haemonchus contortus was measured using two in vitro assays. First, the effects of increasing concentrations of lyophilized extracts (150, 300, 600, 1200 microg/ml PBS) were tested on H. contortus larvae (L(3)) using the larval migration inhibition (LMI) test. An inhibitor of tannin, polyvinyl polypyrrolidone (PVPP), was used to verify whether tannins were responsible for the AH effect. Secondly, the effects of extracts on larval exsheathment were examined. Larvae (L(3)) were in contact with extracts (1200 microg/ml) for 3h, and then were exposed to an artificial exsheathment procedure with observations of the process at 10 min intervals. A general lineal model (GLM) test was used to determine the dose effect in the LMI test and the difference of the percentage of exsheathed larvae between the control and the treatment groups. A Kruskal Wallis test was used to determine the effect of PVPP on LMI results. The LMI test showed a dose-dependent anthelmintic effect for A. pennatula, L. latisiliquum and L. leucocephala (P<0.01), which disappeared after PVPP addition, confirming the role of tannins. No effect was found for P. piscipula on H. contortus in the LMI test. However, all four plant extracts interfered with the process of L(3) exsheathment which might be involved as a mechanism of action of tannins on H. contortus larvae. A. pennatula, L. latisiliquum and L. leucocephala could be used as an anthelmintic for the control of H. contortus after confirmation based on in vivo studies.
Available from: Braulio Valles
- "Leucaena leucocephala preparations have been used in traditional medicine mainly for its anti-inflammatory and anti-diabetic activities (Souza Pinto et al., 1995; Syamsudin et al., 2010). Furthermore, L. leucocephala has been reported to have AH properties against some of the most important GINs of small ruminants, involving tannins/polyphenols as the phytochemical group responsible for the AH effect (Ademola et al., 2005; Alonso-Diaz et al., 2008). Similar results were found against cattle nematodes where L. leucocephala aqueous extracts inhibited both egg hatching and the exsheathment process of Cooperia spp. "
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ABSTRACT: Leucaena leucocephala is a tropical forage legume suggested as an alternative method to control gastrointestinal parasitism in ruminants. This study: (1) performed a bio-guided fractionation of an aqueous extract of L. leucocephala using the egg hatch assay (EHA) to identify the anthelmintic (AH)-like phytochemicals present in fresh leaves, and (2) assessed the ultrastructural damage to eggs of Cooperia spp. after incubation with the final fraction. Phytochemicals were isolated using silica gel columns and identified using high performance liquid chromatography and standards for comparison. The final fraction was evaluated using EHA at 0.06, 0.125, 0.250, 0.500 and 1.1mgml(-1). The lethal concentration to inhibit 50% of Cooperia spp. egg hatching (LC50) was calculated using a Probit analysis. Scanning and transmission electron microscopy revealed the ultrastructural changes present in Cooperia spp. eggs. Bio-guided isolation procedures led to the recognition of an active fraction (LlC1F3) mainly composed of quercetin (82.21%) and caffeic acid (13.42%) which inhibited 90.49±2.8% of Cooperia spp. egg hatching (P<0.05), and an LC50 of 0.06±0.14mgml(-1). Scanning electron microscopy (SEM) showed eggs exposed to the active fraction had an irregular external layer with small projections and ruptures of lateral eggshell walls. Transmission electron microscopy (TEM) showed changes to Cooperia spp. eggs in electro-density, including the thickness of the eggshell layers and fractures after incubation with the final fraction (LlC1F3). Changes in bioactivity after purification suggest synergistic interactions between quercetin and caffeic acid.
Available from: Manuel Mateo Hernandez Villegas
- "In previous studies, similar or higher concentrations of plant extracts have been used to control H. contortus (Costa et al., 2008; Alonso-Díaz et al., 2008; Manolaraki et al., 2010). Alonso-Díaz et al. (2008) using Lysiloma latisiliquum, Acacia pennatula and Leucaena lucocephala, showed that 1.2 mg/mL of plant extract inhibited 33.0%, 43.0% and 44.0% of larval migration of H. contortus, respectively. "
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ABSTRACT: The in vivo anthelmintic (AH) activity of the ethanolic extract from leaves of Phytolacca icosandra was evaluated in goats artificially infected with Haemonchus contortus. Parasite naïve goats were artificially infected with 3000 H. contortus infective larvae per animal. Once the infection was patent (day 28 post-infection) all the animals were sampled to determine the faecal egg counts (FEC) for five consecutive days. Two groups of animals were formed balanced for their FEC and body-weight (BW) (n=6/group): the non-treated control group and the treated group in which goats were individually administered with the ethanolic extract of P. icosandra. The extract was administered orally using gelatin capsules (250mg/kg BW) which were dosed on two consecutive days using a pill-dispenser. Faecal samples were collected from each animal from the day of dosage (Day 0) on a daily basis to determine the number of eggs per gram of feces (EPG) for 15 days post-treatment (PT). The FEC of the two groups were compared using the repeated measures analyses of variance using the log transformed data Ln (FEC+1). The presence of saponins, coumarins, flavonoids, steroids and terpenoids were detected by standard methodologies in the extract. The P. icosandra ethanolic extract was further analyzed by gas chromatography (GC) coupled to a mass spectrometry (GC-MS). A significant reduction in FEC was observed in the treated group compared to the control from day 7 until day 15 PT (P<0.05). The highest percentage reduction (72%) was found on day 11 PT. No adverse reactions were observed in all treated animals for the entire trial. The GC-MS analysis of the organic extracts revealed the presence of three fatty acids as compounds with highest abundance. The three compounds that were identified by their mass fragmentation patterns were: 2-Pentadecanone, 6, 10, 14-trimethyl (RT 10.3min), Pentadecanoic acid, 14-methyl-, methyl ester (RT 10.8min) and Hexadecanoic acid, ethyl ester (RT 11.2min). It is concluded that the P. icosandra ethanolic extract obtained from leaves showed in vivo anthelmintic activity against H. contortus when administered orally to goats at a dose of 250mg/kg BW on two consecutive days. The dose used did not cause any negative effects on the health of goats.
- "parasites and plant extracts from Yucatan, Mexico) seemed to be less sensible to the AH effect of the local source of tannins than other H. contortus strains from regions of Mexico different to that of the tannin sources. Furthermore, the H. contortus from France were even more sensible to that same tannin source (Alonso-Diaz et al., 2008b; Calderón-Quintal et al., 2010). "
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ABSTRACT: Gastrointestinal nematodes (GIN) could have a negative impact on the nutritional efficiency and productivity of sheep and goats. However, feeding of the hosts can also affect parasites. This paper reviews literature data on nutritional manipulation of small ruminants as a tool for the control of GIN under hot humid and subhumid tropical conditions. Parasites are integrated into the food chain of foraging small ruminants. A balanced grazing system provides an adequate source of nutrients and an acceptable GIN burden that allows an optimum level of productivity. However, a breakdown in such balance may induce severe parasite infections. Diet manipulation strategies have been tested under tropical conditions. Animals receiving supplementary feeding may achieve an improved resilience against GIN infections. However, the improvement of resistance of sheep and goats against GIN through supplementation has been less studied and many confounding factors should be considered (pattern of fodder consumption, dilution of eggs in the faeces, direct anthelmintic (AH) effect of some ingredients, etc.). Some supplements cause a direct AH effect (i.e. copper wire particles against Haemonchus contortus). Meanwhile, bioactive plant secondary metabolites (PSM), such as tannins, are more complex. Some PSM may cause negative effects in the host (i.e. reducing feed digestibility), and yet animals consume bioactive plants at levels that can cause evident negative effects to the parasites. The GIN can be affected in different stages of their life cycle (i.e. adults with fewer eggs in utero or reduced worm burdens). Meanwhile, they can also affect new infections for the host (affecting egg hatchability and larvae motility in the faeces or avoiding exsheathment of incoming infective larvae in the host). Grazing management should be explored in most hot humid and subhumid tropical regions. Available results suggest that alternate and rotational grazing can both provide opportunities to reduce dependence on AH and can easily be complemented with supplementary feeding. More basic knowledge of animal nutrition and GIN epidemiology under hot humid and subhumid tropical conditions is needed to improve the applicability of nutritional strategies for the control of GIN infections.
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