Effects of an Oregano Based Dietary Supplement on Performance of Broiler Chickens Experimentally Infected with Eimeria Acervulina and Eimeria Maxima

A study was conducted to examine the effect of dietary oregano essential oil supplementation on the performance of broiler chickens challenged with Eimeria acervulina and Eimeria maxima at 14 days of age. A total of 375 day-old Cobb-500 male chicks separated into 5 equal groups with three replicates each, were used in this study. Two of the groups, one challenged with 1 X 10(5) sporulated oocysts of E. acervulina along with 1 X 10(5) sporulated oocysts of E. maxima and the other not, were given a basal diet and served as controls. The other three groups also challenged with combined E. acervulina and E. maxima were administered diets supplemented with oregano essential oil by adding the product Orego- Stim (containing 5% oregano essential oil) at the levels of 300 or 600 mg/kg, and the last group the anticoccidial substance salinomycin at the dosage of 60 mg/kg. Following the challenge, survival rate, bloody diarrhea and oocysts excretion, as well as intestinal lesion score were all determined. Throughout the experimental period that lasted 35 days, body weight gain and feed intake were weekly recorded, and feed conversion ratios were calculated. The results showed that dietary oregano oil supplementation in both oregano supplemented groups, attained body weight gains and feed conversion ratios not differing (p>0.05) to those of the non-challenged group or the salinomycin group. The challenged control presented lower (p>0.05) performance than those of the other groups for the consecutive three weeks after the challenge. These performance parameters along with lesion scoring indicated that oregano essential oil exerted an anticoccidial effect against E. acervulina and E. maxima, comparable to salinomycin.