RESUMO
Gastrointestinal (GI) nematodes remain a major constraint on livestock production throughout the world. This study assessed the in vivo efficacy of the powder of Mitragyna inermis leaves in three breeds of lambs, namely, West African dwarf lambs (WAD), West African long-legged lambs (WALL), and F1 lambs (cross of a WALL ram with a WAD ewe), artificially infected with 3000 L3s of Haemonchus contortus in a controlled experiment. Fecal sample examination, serological analysis, and necropsy were carried out to determine the egg count, worm burden, and worm fecundity reduction. A dose of 3.2 g/kg body weight (BW) M. inermis was administered per the oral route for three consecutive days and repeated 2 weeks later. Compared with the control, the powder of M. inermis leaves (> 60%) and albendazole (100%) significantly reduced (p < 0.01) fecal egg counts (FECs) in the three breeds of lambs. The posttreatment reduction in FECs fluctuated from 56.99 to 78.75% for WAD lambs, 38.39 to 66.39% for WALL lambs, and 35.55 to 63.11% for F1 lambs (WALL × WAD). Significant differences (p < 0.05) were observed in packed cell volume values before and after infection. M. inermis reduced the egg-laying capacity of female adult worms by up to 60% and eliminated more than 80% of the adult worms of H. contortus in lambs. Furthermore, albendazole reduced the worm count and fecundity of female worms by greater amounts than M. inermis (100%). The findings of this study showed that M. inermis is a good source of bioactive compounds for drug development. According to this result, a 3.2 g/kg BW dose of the plant could be applied for the control of GI nematodes in small ruminants.
Assuntos
Hemoncose/veterinária , Mitragyna , Fitoterapia/veterinária , Preparações de Plantas/uso terapêutico , Doenças dos Ovinos/tratamento farmacológico , Albendazol , Animais , Anti-Helmínticos/uso terapêutico , Cruzamento , Fezes/parasitologia , Feminino , Trato Gastrointestinal/parasitologia , Haemonchus , Gado , Óvulo , Contagem de Ovos de Parasitas/veterinária , Ruminantes , Ovinos , Doenças dos Ovinos/parasitologia , Carneiro DomésticoRESUMO
Bridelia ferruginea (Euphorbiaceae) and Mitragyna inermis (Rubiaceae) are two plants of the beninese pharmacopeia used in vivo for the control of gastrointestinal nematodes (GINs) in small ruminants. The objective of the present study is to explore the mechanism of bioactive compounds involved in the action of these two plants on the third-stage infective larvae (L3s) of Haemonchus contortus. Thus, sheathed L3s of H. contortus were incubated with acetone extracts of B. ferruginea and M. inermis at concentrations of 0, 150, 300, 600 and 1200 µg/mL for 3 h at 25°C. The L3s were then washed and artificially submitted to exsheathment in the presence of sodium hypochlorite solution. The role of tannins was verified by adding a tannin inhibitor, polyvinyl polypyrrolidone (PVPP), to the acetone extracts of these two plants for 2 h at 25°C. Acetone extracts from B. ferruginea and M. inermis inhibited the exsheathment of H. contortus larvae (p < 0.001) and this inhibitory effect was dose-dependent for M. inermis at the concentrations tested. Treatment of B. ferruginea and M. inermis extracts with PVPP was associated with a partial restoration of the exsheathment kinetics of H. contortus larvae (p < 0.001), confirming the predominant role of tannins but also the residual role of other secondary metabolites. These in vitro results suggest that these plants are endowed with anthelmintic (AHs) properties and therefore likely to be used as alternatives to synthetic molecules.