Comparison of the Efficacy of Enrofloxacin Against Escherichia coli or Pasteurella multocida Infection in Chickens

This study compared the efficacy of enrofloxacin, given immediately or 6 hrs after infection against Escherichia coli or Pasteurella multocida. In the first experiment, thirty, 12-week-old male layer chickens were divided into 3 groups of 10 each. Chickens in group 1, 2 and 3 were infected with E. coli serotype O78 by left thoracic air sac injection. Group 1 was given enrofloxacin (10 mg/kg), dissolved in drinking water immediately receiving E. coli. Group 2 was given enrofloxacin 6 hrs after receiving E. coli. Group 3 served as a positive control. In the second experiment, twenty, 16-week-old male layer chickens were divided into 3 groups. Groups 1 and 2 have 7 chickens each and group 3 has 6 chickens. Chickens in group 1, 2 and 3 were infected with Pasteurella multocida by thigh muscle injection. Group 1 was given enrofloxacin (10 mg/kg), dissolved in drinking water immediately after receiving P. multocida. Group 2 was given enrofloxacin 6 hrs after receiving P. multocida. Group 3 served as a positive control. The result revealed that enrofloxacin has efficacy to treat colibacillosis and fowl cholera. Chickens immediately treated with enrofloxacin showed lower mortality both of colibacillosis and fowl cholera infection. The lesion scores of airsaculitis, pericarditis and perihepatitis in the chickens immediately treated with enrofloxacin showed lower than the chickens treated 6 hrs later.