the influence of saccharomyces cerevisie, formic acid and virginiamycin supplementation on the performance, carcass characteristic and the composition of the intestinal microflora in broiler

an experiment was conducted to assess the influences of different growth promoters on performance, carcass characteristic and intestinal microflora of broiler. day-old broiler chicks from arian strain (384) were used in the completely randomized experimental design during 7-42 days of age. eight rations were formulated as a follow 1: control (without growth promoters); 2-control + formic acid (0.25%); 3-control+ viginamycin (250 g/ton); 4-contro + saccharomycis cerevisiae (0.1%); 5-control+ viginamycin (250 g/ton)+ formic acid (0.25%); 6- control+ viginamycin (250g/ton)+ formic acid (0.25%); 7- control+ viginamycin (250 g/ton)+ saccharomycis cerevisiae ( 0.1%); 8- control+ viginamycin (250 g/ton)+ saccharomycis cerevisiae ( 0.1%).. the treatments with 3 repetition and 16 birds per parcel were used. the formulated rations were fed to 384 day-old arian. each treatments consisted 3 replicate with 16 birds per parcel. obtained results indicated that formic acid had no significant effects on all measured parameters, nevertheless supplementation of diet with antibiotic significantly (p<0.05) enhanced all deliberated parameters. better weight gain (p<0.05), fed conversion ratio, carcass characteristic and lower abdominal fat was observed when diet was supplemented with antibiotic alone. growth promoters, especially saccharomycis cerevisiae and viginamycin significantly reduced e.coli in digestive tract of birds.