In Vitro and In Vivo Anthelmintic Efficacy of Essential Oil of Satureja montana (L.) against Gastrointestinal Nematodes of Sheep

Abstract

The development of anthelmintic resistance in gastrointestinal nematodes (GINs) requires the search for alternative strategies. The aim of this study was to examine in vitro and in vivo anthelmintic efficacy of essential oil (EO) of Satureja montana (L.) against GIN of sheep, as well as toxic effects in sheep, in order to evaluate the possibility of its use in the veterinary practice. In vitro Egg Hatch Test (EHT) was conducted at eight different concentrations (50, 12.5, 3.125, 0.781, 0.195, 0.049, 0.025 and 0.0125 mg/mL) of EO. In addition, for the in vivo Faecal Egg Count Reduction Test (FECRT), S. montana EO was administered orally to sheep of two different farms in southern Italy at the mean dose of 150 mg/kg. The chemical composition of EO was determined by GC-MS. In the EHT, S. montana EO showed ovicidal potential against sheep GINs with inhibition of egg hatchability that varied from 17.3-83.0% depending on the used concentration. The EO also showed in vivo anthelmintic potential with the total reduction of FEC of 15.7% and 33.0% at days 7 and 14 after treatment, respectively. No toxic effects were observed during clinical evaluation, blood count and liver function tests of sheep. The main represented compounds of EO were p-cymene (42.8%), carvacrol (28.1%) and γ-terpinene (14.6%). The obtained results suggest that S. montana EO may be used in the sustainable future management of GIN infections in sheep as a complementary and sustainable method to reduce the use of chemicals and to counteract anthelmintic resistance.