Dietary treatments consisted of a basal diet supplemented with 0 (control diet without any antimicrobial), 0.5, 1.0 and 1.5 g/kg commercial bacteriophage product(109pfu/g). In Exp. 2, 200 barrows (average initial BW: 50.5 ± 0.928 kg) were randomly allotted to 4 treatments on the basis of initial BW. There were 5 replicate pens in each treatment with 10 pigs per pen.