THE EFFECTS OF DIFFERENT LEVEL OF SYNBIOTIC SUPPLEMENTATION IN DIET OF BROILER ON GROWTH PERFORMANCE, INTESTINAL HISTOLOGY AND MICROBIAL COLONY

This study was undertaken to investigate the effect of the supplementation ofdifferent levels of synbiotic on growth performance and intestinal physiology of broilerchickens. A total of ۳۶۰-day-old broiler chicks were randomly assigned to ۶ differenttreatments of ۴ replicates, with ۱۵ birds per each replicate. Treatments were control (notany supplement), (zinc bacitracin ۰.۰۴ g/kg), and the remaining four treatments weresupplemented with four different levels (۰.۲۵, ۰.۵, ۰.۷۵ and ۱ g/kg) of synbiotic to thebasal diets.At day ۱۰ and throughout the experimental period, body weight and weight gainsignificantly were increased (P< ۰.۰۵) and feed conversion ratio (FCR) significantly was improved by risinglevel of synbiotic. The control group recorded the poorer FCR than other experimentalgroups (P<۰.۰۵). Up to ۱۰ days, feed intake significantly increased in birds on dietssupplemented with ۰.۲۵ and ۰.۷۵ g/kg synbiotic. However, when assessed over the ۳۵days of the experimental period, feed intake significantly decreased (P< ۰.۰۵) in birdsthat received ۰.۷۵g/kg of synbiotic compared to the other experimental groups. Therelative weight of internal organs was not affected by dietary treatments. Carcass yieldand breast meat significantly were increased (P < ۰.۰۵) by rising levels of dietarysynbiotic. Villi length was significantly affected by treatment, indicating the longer villiin birds on diets supplemented with ۰.۵ g/kg of synbiotic compared to the control.Significantly the shorter villi were observed in birds that received the highestsupplement (۱ g/kg) level of synbiotic. The number of E. coli in the ileum were notaffected by dietary treatments.

کلیدواژه ها:

Broiler ، Symbiotic ، Growth performance ، Intestinal Histology ، Microbial Colony