Abstract
Background:
Among the serious quail diseases is coccidiosis, caused by several Eimeria species, particularly cecal coccidiosis, with considerable economic losses.

Aim:
First, 11 quail flocks showing brownish diarrhea tinged with blood and bloody cecal core were submitted for Eimeria spp. detection. A selected E. tsunodai was used to evaluate the comparative anticoccidial efficacy of a commercial herbal product containing oregano and garlic essential oils (EOs) as a prophylactic supplement via drinking water taking into consideration that it had never been applied in quails’ coccidiosis before.

Methods:
A total of 300 Japanese quails were equally assigned to four groups. One of the groups was given basal drinking water and served as the control (G-4). The remaining groups (G-1, 2, and 3) received drinking water containing herbal (Coxan), chemical (Clazo-Fort), and herbal interchangeably with chemical products, respectively. At 14 days of age, each group was subdivided into two subgroups. The subgroups, 1B–4B were infected with sporulated oocysts of E. tsunodai (4.1 × 104).

Results:
The infected group showed a typical cecal lesion of E. tsunodai which was confirmed histopathologically by the presence of different developmental stages in both intracellular lining and cecal content. The alternative herbal product had the highest anticoccidial index with a value of 154.88. Anticoccidial sensitivity test and reduction of lesion score were 77.3, which indicated both herbal and chemical products were sensitive against E. tsunodai. Additionally, quails supplemented with Coxan had the highest BWG (p < 0.05). Additionally, a high HI antibody titer against NDV was obtained in the Coxan group with a significant increase (7.66 ± 0.67 log 2; p = 0.039) at 21 days of age and a high CD4 antigen value (1762 ± 87.5 pg/ml) in sera at 14 days of age. In the jejunum of the Coxan group, a significant increase in villi length was associated with a reduction in the crypt depth, and the highest villi length and crypt depth ratio were represented, accompanied by a higher count of intestinal lactobacillus (p =0.0236) compared to the infected group.

Conclusion:
The prophylactic supply of alternative herbal products containing oregano and garlic EOs could be a safe, potent anticoccidial in quails that is consistent with the world’s transition to a green economy besides its immunestimulant properties.

Key words: Japanese quails, E. tsunodai, Essential oils, Anticoccidial index, Intestinal morphology