We conducted this study at the Department of Veterinary Public Health, College of Veterinary Medicine, University of Baghdad over a period of 4 months to evaluate the effect of adding vitamin AD3E, folic acid, Selenium (Se), and Zinc (Zn) as dietary supplements on hematological and biochemical parameters of laying hens during the production period. A total of 105 commercial Lohmann Brown laying hens were used and divided into seven treatment groups (15 hens per group), which were T1: control group fed basal diet; T2: AD3E (1 g/kg feed) + basal diet, T3: folic acid (15 mg/kg feed) + basal diet T4: Zn (120 mg/kg feed) + Se (0.2 mg/kg feed) + basal diet, T5: AD3E + folic acid + basal diet, T6: AD3E + Se + Zn + basal diet, T7: AD3E + folic acid + Se + Zn + basal diet for a period of four months of egg production. The results showed a significant (P≤0.05) and (P≤0.01) in all blood cellular .The parameters of biochemical, enzyme and antioxidant was record significant (P≤0.05) and (P≤0.01) .The treatment T7 recorded blood cell count RBC (3.45), packed cell volume PCV (37.165), and hemoglobin Hb concentration(12.25). Additionally, a decrease in H/L ratio(0.29) and the oxidative stress index MDA (0.31) were observed due to an improvement in immune status and reduced stress comparative with the control group it show RBC(2.96),PCV(31.91),Hb(10.25), H/L ratio (0.33) and MDA ratio (0.56),. Biochemical parameter values revealed improvements in protein metabolism and decreased liver enzyme activity. Combined nutritional supplements improved all blood cellular parameters, immunity, overall health performance, and reduced physiological stress of laying hens.
