Résumé
The aim of the present work was to study the growth promoting effect of some antibiotics namely flavomycin and enramycin and two probiotics bio nutra and dinaferm on Hubbard broiler chickens. Birds were divided into five equal groups, each of 50 chicks. The 1st group received only basal ration [control]. The 2nd and 3rd groups received flavomycin and enramycin [120 gm /ton] respectively, the 4th and 5th groups received bionutra and dinaferm [[kg/ton] respectively Weights of birds and amount of food consumed by the birds were recorded weekly, also number of dead birds were recorded. It was found that the highest significant value of feed conversion was in dinaferm treated group followed by enramycin control and bio nutra. There was no significant differences between them. The lowest feed conversion was found in flavomycin treated group, also the least number of dead birds was found in enramycin treated group. So,it is better to use flavomycin than other treatments at a dose of 120 gm/ton to improve feed conversion, while enramycin is recommended in order to decrease mortality at a dose of 120 gm/ton it could be also concluded that some probiotics as bio nutra can be used as alternatively to growth promoting antibiotics where mortality rate is low