Our study is intended to investigate the efficiency of the antibacterial activity of different materials such as antibiotic, organic zinc and zinc oxide nanoparticles (ZnO NPs) which experimentally tested against field avian pathogenic Escherichia coli (APEC) isolates. The study was carried out in a private broiler farm, 10 birds out of 60 (one-day-old-chicks) which were housed for 35 days were slaughtered and samples were taken from liver, lung and heart blood were positive for E. Coli., these samples were cultured on special bacteriological media the remaining 50 birds were free from E. Coli. were divided into 5 groups 10 birds in every group, Group (1) free from E. coli infection and not treated kept as (negative control) Group (2) infected with isolated E. coli and not treated kept as (positive control). Group (3) infected with isolated E. coli and treated with difloxacin (10 mg/kg per day) on drinking water for 5 successive days for 3 times per day. Group (4) infected with isolated E . coli and treated with organic Zn (50 mg/kg) on drinking water for 5 successive days for 3 times per day. Group (5) infected with isolated E . coli and treated with ZnO NPs (100 mg/kg) on drinking water for 5 successive days for 3 times per day.
It was noticed that E. coli isolated from diseased broilers at an average incidence rate of 20%, recorded with highest resistant rate to erythrocin, gentamycin, tetracycline and amoxicilin( 71.4 , 57.1,57.1 and 42.9 %, respectively) and highest sensitivity rate to difoxacin, amoxicillin and tetracycline (76, 28 and 23%, respectively)  with minimal inhibitory (MIC), the birds treated with ZnO-NPs (G5) showed significant increase in Hemoglobin concentration , RBCs , PCV ,WBCs count in ZONPs group comparing with control group . While, Serum cholesterol, triglyceride, low density lipoprotein, creatinine, uric acid and liver function test decreased Significantl, Also high density lipoprotein and innate immunity (IgA & IgM) were significantly increased in ZONPs group than control
In conclusion The therapeutic effect of ZnO Nano particles is recommended as an effective antimicrobial alternative against APEC strains.