Anthelmintic activity of Eucalyptus staigeriana encapsulated oil on sheep gastrointestinal nematodes

The anthelmintic activity of Eucalyptus staigeriana essential oil has previously been inferred through both in vitro and in vivo tests. Thus, the encapsulation process generally improves oil stability, promotes controlled release in target organs, reduces dosage, and increases efficacy. The aims of this study were to analyze and encapsulate E. staigeriana essential oil and to verify its anthelmintic activity in sheep. The encapsulation process was accomplished through emulsion using a 4 % chitosan solution as the matrix. Anthelmintic activity was established through controlled testing using 18 sheep that were separated into three groups: group 1 was treated with a single dose of 365 mg/kg of E. staigeriana encapsulated oil, group 2 was treated with 200 μg/kg of ivermectin, and group 3 was treated with a 4 % chitosan solution as a negative control. The sheep were euthanized and necropsied 13 days posttreatment to evaluate worm burden. Limonene was the major oil component (72.91 %). The final product was a hydrogel with 36.5 % (m/m) E. staigeriana essential oil per gram. Its efficacy on gastrointestinal nematodes was 60.79 %. The highest efficacy was against abomasal nematodes, with 83.75 % efficacy. Further studies are necessary to explore the possibility of increasing the hydrogel efficacy; nevertheless, we can state that E. staigeriana encapsulated oil had anthelmintic activity and can be used in gastrointestinal nematode control.