Nematicidal activity of aqueous and hydroalcoholic extracts of pleurotus ostreatus against the nematode haemonchus contortus

Abstract

Haemonchus contortus is the most harmful, prevalent, and economically significant parasite in sheep. Recent studies have explored the efficacy of fungal extracts as a biological control strategy. The present study evaluates the nematicidal activity of both aqueous and hydroalcoholic extracts of Pleurotus ostreatus against L3 larvae of H. contortus. The fungi used were sourced from five production units in the Amecameca region, State of Mexico. Aqueous extracts were prepared using distilled water, while hydroalcoholic extracts employed a 70:30 ethanol-water solution processed by rotary evaporation; all extracts were subsequently lyophilized. Larvae were obtained through artificial infection of a donor sheep (350 L3/kg BW). Bioassays were conducted using a dose of 20 mg/mL, with L3 larvae exsheathed in 0.187% sodium hypochlorite. Distilled water served as the negative control, and ivermectin (10 mg/mL) as the positive control. Each assay included ten readings, three repetitions, and a 72-hour exposure per extract. Mortality rates for the aqueous extracts ranged from 26.13 to 69.54%, while hydroalcoholic extracts resulted in mortality rates between 3.68 and 18.15%. Controlling H. contortus remains a considerable challenge; effective management requires minimizing parasite presence and mitigating its impact on the health and welfare of sheep.