Cecal coccidiosis is a significant parasitic disease that affects poultry farms and is
caused by Eimeria tenella. This study evaluated the anticoccidial efficacy of oregano oil
and allicin against Eimeria tenella in experimentally infected broiler chickens. One
hundred and twenty-one-day-old chicks were divided into six groups (20 chicks in each
group): G1, non-infected non-treated (control negative group); G2, the infected nontreated (control positive group); G3 was treated with amprolium; G4 was treated with
oregano oil, G5 was treated with allicin, andG6was treated with a mixed dose of oregano
oil and allicin. All groups were challenged with 104 Eimeria tenella sporulated oocysts at
the 5th day old except the first group (G1). Body weight (B.W), food conversion rate
(FCR), oocyst count, hematology, serum biochemical parameters, and histopathology
were assessed throughout the experiment in all groups. Oregano oil and allicin
significantly improved B.W., FCR, lesion score, and oocyst count. Additionally,
histopathology showed that the oregano oil and allicin successfully treated the cecum
thoroughly; the cecum was average in its histology with the absence of E. tenella
developmental stages. In conclusion, this study proved that oregano oil and allicin have
a protective and curative effect as anti-coccidial drugs of plant origin on E. tenellainfected chickens. Furthermore, the mixture of the two chemicals is a promising treatment for E. tenella infection in broiler chickens.