Potential of plant extracts to inhibit egg hatching and migration of Haemonchus contortus larvae

Abstract

One of the main problems that affects sheep production based on the grazing system has been the infestation by gastrointestinal nematodes, not only in Mexico, but throughout the world, they constitute important animal health problems that worsen over years due to the inappropriate use of medications to control it and cause resistance to anthelmintics. The use of plants with anthelmintic potential offers biological control without anthelmintic resistance. Objective: To evaluate the potential of Azadirachta indica (AZA) and Moringa oleifera (MOR) extracts to inhibit egg hatching and in vitro displacement (migration) or tropism of Haemonchus contortus larvae. Methods: A completely randomized experimental design was carried out, where 15 treatments and a negative control of dimethyl sulfoxide were evaluated: MOR-75, MOR-50, MOR-25, MOR-12.5 and MOR- 6.25 mg/mL; AZA-75, AZA-50, AZA-25, AZA-12.5 and AZA-6.25 mg/mL; and thiabendazole (TBZ) TBZ-200, TBZ-100, TBZ-40, TBZ-20, TBZ-10 μg/mL. Results and Discussion: The extracts did not inhibit the hatching capacity of the eggs; however, a decrease in motility of up to 100% was observed in L1 larvae. The extracts affected larval migration (P<0.0020) compared to controls (dimethyl sulfoxide and TBZ), with an inhibition of the migration rate greater than 65%. Probit analysis showed that the median effective concentrations were 60.41 and 65.69 mg/mL for M. oleifera and A. indica, respectively.