The current work was carried out to explore protective properties of commercially available probiotic (Lacto G^®) and prebiotic (Immunolin^®) preparations on performance traits, lesion scores, shedding of oocysts and some immunological parameters in Eimeria tenella infected broiler chickens.  A total of 108 one-day-old broiler chicks were randomly divided into six groups: 1) probiotic non-challenged; 2) prebiotic non-challenged; 3) probiotic challenged; 4) prebiotic challenged; 5) non-treated challenged (positive control); 6) non-treated non-challenged (negative control). Chicks were challenged with E. tenella oocysts (4x10⁴) at 21 days of age.  Supplementation with probiotics or prebiotics did not significantly improve the body weight or feed conversion ratio of birds compared to control. No mortality was recorded in the 3^rd group while a high mortality rate (20%) was detected in the 4^th and 5^th groups. Lesion scores were significantly reduced in the 3^rd group, while the 4^th did not show any improvement in comparison with the infected group. The total number of oocysts starting from 7^th up to 13^th day post-challenge (PC) was significantly reduced in the 3^rd and 4^th groups in comparison with the control infected group. It could be concluded that there was a protecting effect of the probiotic and prebiotic preparations used, that helped to reduce the negative effects of coccidiosis but was not associated with an improved growth performance.

Key words: Probiotic, Prebiotic, Coccidiosis, Eimeria tenella, Broilers