The Use of Essential Oils against Sheep Gastrointestinal Nematodes

Abstract

Gastrointestinal nematodes (GINs) nowadays present a serious threat to sustainable sheep breeding. Various classes of commercial anthelmintics were used to control these parasites. However, due to the development of anthelmintic resistance (AR), the efficacy of these drugs has decreased, which in turn resulted in high economic losses. For these reasons, researchers are focused now on designing sustainable strategies for GIN control, based on the use of a combination of a bunch of options including the wise application of anthelmintic drugs, as well as applying alternative strategies. Within this context, phytotherapy (the use of plants or their products) presents one of the most promising alternatives. Essential oils (EOs) are natural, volatile and complex compounds characterized by a strong odor and extracted from aromatic plants. In various studies so far, these plant products showed high in vitro and, in some cases, in vivo efficacy against sheep GINs. The aim of this chapter is to review so far conducted studies based on the use of EOs against these parasites and to discuss results, as well as advantages of their use compared to commercial anthelmintics. On the other hand, current obstacles in the use of EOs and possible solutions on how to overcome them will be also discussed in this chapter. In this way, current and future perspectives of the use of EOs against sheep GINs are discussed here.