The In Vitro Anticoccidial Activity of Some Herbal Extracts against Eimeria spp. Oocysts Isolated from Piglets

Coccidiosis in pigs seldom results in important economic losses. However, it can influence growth rates in weaners and it is an important hygiene indicator in swine farms. Certain herbs, along with their extracts, have been used over the course of history in traditional medicine. The aim of this study was to evaluate the in vitro anticoccidial effects of Allium sativum L. (garlic), Artemisia absinthium L. (wormwood), Coriandrum sativum L. (coriander), Cucurbita pepo L. (pumpkin), Satureja hortensis L. (summer savory), and Calendula officinalis L. (marigold) against Eimeria suis and Eimeria debliecki oocysts. The stock solution of oocysts (58% E. suis + 42% E. debliecki) was incubated for three days, before adding the tested solutions. The unsporulated Eimeria spp. oocysts were then placed in a 3 mL well plate and incubated for 96 h at 27 °C, in a suspension containing serial dilutions of alcoholic plant extracts (5%, 2.5%, 1.25%, 0.625%, and 0.312%). The percentage of sporulated and destroyed oocysts was recorded every 24 h for 96 h. All extracts had a good in vitro anticoccidial effect against oocysts of Eimeria spp. compared with the control groups. Oocyst sporulation was significantly (p = 0.05) inhibited by the 5% marigold extract (3.6% sporulated oocysts). The same extract had the highest lytic effect on oocysts (65.2% destroyed oocysts). Our results prove that the most effective alcoholic plant extract is the marigold extract, followed, in order of efficiency, by the wormwood, coriander, garlic, pumpkin, and summer savory extracts. This study represents a preliminary contribution for establishing a new generation of natural disinfectants aimed at destroying Eimeria oocysts in the context of swine contamination.