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This work was carried out to evaluate the efficacy of oregano powder 10% used as a prophylactic treatment in broiler chickens experimentally infected with avian pathogenic E. coli O27 (APEC O27) strain -local isolate-.Hematological and serum biochemical parameters, as well as histopathology of the vital organs, were investigated. A total of 200 chickens -aged 19 days old-were randomly allocated into 4 equal groups; Normal control (G1), Infected (G2), Oregano control (G3), and Oregano-Infected (G4). Chickens of (G3) and (G4) were supplemented with oregano powder that contains 10% oregano essential oil in the diet (250 g /ton diet) from the 1 st day old till the end of the experiment.At the age of the 19th, 20th, and 21st day,chickens of (G2), and (G4) were infected with 0.2 ml of APEC O27 (1×10 7 CFU/chick) via the intratracheal route. On the 3 rd , 6 th , 10 th , and 21 st day post-infection, blood and tissue samples from all groups were collected for laboratory examinations of the hemogram, serum biochemistry, and histopathology of the vital organs. Chickens of (G2) showed gasping, dullness, loss of appetite, and ruffled feathers. Birds of (G3) showed nosymptoms, while those of G4 showed mildsymptoms. The mortality rates in chickens of (G2), (G3), and (G4) were recorded 30%, 0%, and 4%, respectively. Birds of (G2) revealed macrocytic hypochromic anemia, leukocytosis accompanied by heterophilia, and lymphopenia. The activities of AST and ALT enzymes and the values of uric acid and creatinine were increased while those of protein profile were decreased. In oregano supplemented groups, no significant alterations were detected. Birds of (G2) and (G4) revealed histopathological alterations in the lungs, trachea, liver, spleen, and kidneys.Finally, APEC O27 caused changes in blood picture, liver and kidney functions as well as histopathology of the internal organs. Oregano powder (at a dose of 10% in diet) could be used as prophylactic treatment for APEC O27 in chickens from the 1 st day of age.

This study aimed to evaluate the efficacy of oregano oil 20% for the treatment of broiler chickens experimentally infected with avian pathogenic Escherichia coli O27 (APECO27) -local isolate. Hemogram, biochemical constituents, and histopathology of the internal organs were assessed. Two hundred chicks -19-days-old-were randomly assigned to four equal groups; G1 (normal control), G2 (Infected), G3 (oregano treated), and G4 (antibiotic treated). At the 19 th , 20 th , and 21 st day of age, G2, G3, and G4 were intratracheally infected with 0.2ml of APECO27 (1×10 7 CFU/chick). On the 22 nd , 23 rd , and 24 th day of age, G3 & G4 were treated with oregano 20% (2ml/5liters) and difloxacin (10mg/kg b.wt.) in drinking water, respectively. On the 3 rd , 6 th , 10 th , and 21 st day post-infection, blood and tissue samples were collected for laboratory investigations of the hemogram, serum biochemistry, and histopathology of the internal organs. Infected non-treated G2 chicks showed dullness, ruffled feathers, gasping and loss of appetite, while infected-treated G3 & G4 birds showed mild symptoms. The mortality rate was 30%, 8% and 4% in G2, G4 and G3, respectively. Chicks of G2 & G4 developed macrocytic hypochromic anemia, leukocytosis, heterophilia, and lymphopenia. Values of ALT, AST, creatinine, and uric acid were increased while protein profile was decreased. After oregano treatment, alterations were returned to normal levels. Histopathologically, chicks of G2 & G4 showed alterations in the internal organs. Finally, APECO27 caused alterations in hematology and serum biochemistry, and histopathology of the internal organs. Oregano could be used as antibiotic for the treatment of APECO27.

T HIS study aimed to evaluate the most predominant strain of avian pathogenic Escherichia coli (APEC) that causes colibacillosis with respiratory manifestation in broiler chickens. Isolation and serotyping identification for the isolates of E. coli were performed. Prevalence of APEC differentiated by detection of the 8 virulence-associated genes "astA, iss, irp2, papC iucD, tsh, vat, and cva/cvi" using multiplex PCR technique in the most important isolates of E. coli was also investigated. Antibacterial sensitivity test for antibiotics disc and oregano at different concentrations (20%, 15%, 10%, and 5%), were estimated for the most important isolates of E. coli. A total of 50 broiler farms were located in Gharbia, Giza, Menoufia, Bahaira, and Dakahliah Governorates were examined. Specimens from lung, liver, spleen, and kidney from diseased birds were used for bacteriological examination. Results revealed that E. coli O27 was the most predominant serotype strain (11 out of 35 isolates), followed by the serotypes of O146 (4/35), O Untypable serotypes (4/35), and the (1/35) of each serotype of O8,