effects of medicinal plant, prebiotic, probiotic and antibiotic on intestinal morphology and nutrient digestibility of broilers chickens

the present experiment was carried out to determine the effects of  antibiotic  growth promoters, blend of medicinal plants, prebiotic and organic acid on performance and nutrients apparent digestibility in a six week period, using one hundred ninety two one- day- old broiler chicks (cobb 500) on a randomized complete block design experiment with six treatments consisting of 4 replications and 8 chicks per pen in cage condition. experiment treatments were included: 1- control (without growth promoters) 2- antibiotic (15 ppm virginiamycin ) 3- blend of medicinal plants (450 ppm digestarom) 4- prebiotic (0.1 % immunowall)  5- organic acid (0.2% blend of organic acid salts)  6- mixture treatment 4 and 5. body weight gain and feed conversion ratio were not affected by dietary treatments (p>0.05).however feed intake significantly were affected experimental groups. no significant differences in nutrients apparent digestibility compared with control were observed in starter and grower periods.