Study of Doxicycline Efficacy in Broilers’ Colibacilosis

The aim of study is a therapeutic assessment of doxicycline’s hyclate efficacy, a wide spectrum antibiotic (efficient in majority of bacterial Gram-positive and Gram-negative infections and mycoplasmas, frequently isolated in poultry) in a colisepticemia outbreak in a 3,000 chicken farm. Disease started at the broiler’s age of 20 days and mortality rate reached 32.5%. The behaviour to antibiotics of isolated bacterial strains was tested and antibiogram (Sanofi) was used, doxicycline revealing a very good antibiotic activity. The treatments (with the dose of 10 mg x kg.b.w.-1) were done individually for five days, clinical evolution being observed until day ten of the experiment. Analyzing evolutions after treatments it was observed that the mortality diminished progressively from 14.2% in the first day, to 8.3% - 5.9% - 2.5% - 1.7% and respectively 0.8% in the sixth treatments day, in days seven, eight, nine, and ten of the study not being registered any mortality cases. In our opinion the favorable clinical evolution was recorded after the third treatment day, at the end of experiment from 120 remaining live 80 chickens (representing 66.7%) proving the fact that doxicycline was efficient, confirmed also by the average daily weight gain for the remaining live chickens.