ABSTRACT
The therapeutic efficacy of kitasamycin following oral administration of 300 or 600 mg/kg. b. wt. for five successive days against experimental E.coli infection in broiler Hubbard chicken was studied. Effect on body weight gain and feed conversion from 3 weeks were of age till the end of 6 weeks also investigated. Moreover, tissue distribution of kitasamycin in normal and E.coli-infected chicks were recorded. Results achieved showed that administration of kitasamycin at the same time of infection, reduced morbidity, mortality and development of lesions more effectively than its administration after the appearance of symptoms in therapeutic or double the therapeutic doses. Kitasamycn improved significantly body weight gain and feed conversion, especially when given at the same time of E.coli infection. Kitasamycin [300 mg/kg. b. wt.] Was detected in serum of E.coli-infected chickens as early as 5 minutes and after 10 minutes in serum of normal birds following administration. It reached peak concentration one hour after administration and its level was slightly higher [7.4 +/- 0.78 micro g/ml] in serum of infected chickens versus normal birds [6.2 +/- 0.37 micro g/ml]. The concentration of the drug was high he in bile, ceacum, intestine, gizzard and lung than in muscles, fat and spleen. Kitasamycin could not be detected in brain at any interval following administration