Effect of growth promotor [virginiamycin] on broiler performance under Egyptian environment

ABSTRACT

Two groups each of 500 one-day old Red Hypeco chicks were fed on basal diet [group C], while other group [group V] was fed basal diet supplemented with 20 ppm virginiamycin. Virginiamycin supplementation gave better body weight gain, less feed consumption, better FCR, less mortality rates and better dressing values than the control group. E. coli [01K1 and 078K80] was isolated from both groups at the age of one day old and 24 days old respectively. E. coli 01K1 and proteus vulgaris were isolated from cloacal swab at 49 day old. Virginiamycin had an effect on E. coli plate count for cloacal swab at 49 day old and was 30 x 10[11] and 30 x 10[16] for group V and C respectively. Virginiamycin had no significant immune stimulus effect on the immune response against ND and IBD