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Age of Haemonchus contortus third stage infective larvae is a factor influencing the in vitro assessment of anthelmintic properties of tannin containing plant extracts

Castañeda-Ramírez, Gloria Sarahí and Mathieu, Céline and Vilarem, Gérard and Hoste, Hervé and Mendoza-de-Gives, Pedro and González-Pech, Pedro Geraldo and Torres-Acosta, Juan Felipe de Jesús and Sandoval-Castro, Carlos A. Age of Haemonchus contortus third stage infective larvae is a factor influencing the in vitro assessment of anthelmintic properties of tannin containing plant extracts. (2017) Veterinary Parasitology, 243. 130-134. ISSN 0304-4017

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Official URL: https://doi.org/10.1016/j.vetpar.2017.06.019


The larval exsheathment inhibition assay (LEIA) of infective larvae (L3) is an in vitro method used to evaluate the anthelmintic (AH) activity of tannin-containing plant extracts against different species of gastrointestinal nematodes, including Haemonchus contortus. Some conditions remain to be defined in order to standardize the LEIA, i.e. the optimal age of larvae produced from donor animals to use in the assays. Therefore, this study aimed at identifying the effect of age and age-related vitality of H. contortus infective larvae produced under tropical conditions, on the in vitro AH activity measured with the LEIA. The same acetone:water (70:30) extract from Acacia pennatula leaves was used to perform respective LEIA tests with H. contortus L3 of different ages (1–7 weeks). Each week, the L3 were tested against different concentrations of extract (1200, 600, 400, 200, 100, 40μg/mL of extract) plus a PBS control. Bioassays were performed with a benzimidazole (Bz) resistant H. contortus (Paraíso) strain. In order to identify changes in L3 vitality on different weeks (1–7), two assays testing larval motility were included only with PBS: the larval migration assay (LMA) and the larval motility observation assay (LMOA). Mean effective concentrations causing 50% and 90% exsheathment inhibition (EC50, EC90) were obtained for every week using respective Probit analyses. On the first week, the larvae had lowest EC50 and EC90 (39.4 and 65.6μg/mL) compared to older larvae (P<0.05). The EC50 and EC90 for weeks 2–5 were similar (P>0.05), while older larvae tended to show higher EC50 and EC90 (P<0.05). Motility showed strong negative correlations with age of larvae (r≥−0.83; P <0.05) and EC50 (r≥−0.80; P<0.05), suggesting that the lower extract efficacy could be associated with decaying vitality of larvae associated with age. More stable efficacy results were found between two to five weeks of age.

Item Type:Article
HAL Id:hal-01608383
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Centro Nacional de Investigación Disciplinaria en Parasitología Veterinaria - INIFAP (MEXICO)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
French research institutions > Institut National de la Recherche Agronomique - INRA (FRANCE)
Other partners > Universidad Autónoma de Yucatán - UADY (MEXICO)
Laboratory name:
Mexican National Council for Science and Technology - CONACYT Mexico - CONACYT PCP between Mexico France
Deposited On:26 Nov 2019 17:39

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