The objective of this study was to evaluate the effect of probiotic, Pediococcus acidilactici (CNCM-MA 18/5 M, Lallemand, France) in concentrations of T1: 1 × 10⁹, T2: 2× 10⁹ and T3: 3×10⁹ cfu / kg of diet on changes some hematological parameters of bream fry (Abramis brama orientalis, Berg 1949) in comparison with diet control, C, (untreated) for 60 days. One hundred eighty Bream fry with randomly in initial weight of 2.69± 0.22 g divided in 12 fiberglass tanks (110 L) and offered feed at 3-5% body weight, daily. At the end of the trial blood parameters measured. The total number of red blood cells, hematocrit, hemoglobin and white blood cells levels showed a significant increase in treatment fed with 2× 10⁹ cfu probiotic per kilogram of diet (P<0.05). Indifferential white blood cell(WBC) count, the number of neutrophils and monocytes, and lymphocytes increased significantly in treatments fed with probiotics. The highest increase in neutrophils and monocytes, and the highest decrease in lymphocytes observed in T₃ (3× 10⁹ cfu kg^-1). According to the results, it concluded that adding probiotic Pediococcus acidilactici to the fry bream (Abramis brama orientalis, Berg 1949) diet, increase blood parameters related to red blood cells (RBC), diseases resistance and improve non specific immune response in bream.

According to the results, it concluded that adding probiotic Pediococcus acidilactici to the fry bream (Abramis brama orientalis Berg 1949) diet, increase blood parameters related to red blood cells (RBC), diseases resistance and improve non specific immune response in bream.