Compensation of detrimental effects of feed restriction on growth performance and intestinal morphometric indices in broiler chickens by synbiotics

This experiment was conducted to investigate the effects of using probiotic, prebiotic and synbiotic during feed restriction on growth performance and intestinal villus morphology in broiler chickens. A total of 240 Ross 308 broilers were divided into 5 experimental treatments including a control group and 4 feed restriction groups and reared on litter floor for 42 days. The control group was a full-feed group where birds received a basal diet with no additive and had free access to feed throughout the experiment (FF). The feed restriction groups were deprived of feed from 10 to 38 days of age for 6 h per day and received a basal diet with no supplement (FR) or supplementation with probiotic, prebiotic or symbiotic. All feed-restricted birds had significantly lower body weight gain during the restriction period (P < 0.05). However, birds in synbiotic and probiotic groups, but not the prebiotic group, showed compensatory growth during the refeeding period. Feed restriction significantly decreased the abdominal fat percentage as well as villus height, villus width, villus height to crypt depth ratio and villus surface area in all three segments of the small intestine (P < 0.05). All three additives improved intestinal morphometric indices in the feed restricted groups, but probiotic and symbiotic were more effective than prebiotic. Results from this study revealed that supplementing synbiotic in broilers' diet is more effective than probiotic and prebiotic in improving growth performance as well as intestinal morphometric indices during feed restriction.