Effect of feed additives on small intestinal morphology, mineralization and strength of tibia bone of broilers and laying hens

Two experiments were conducted to evaluate the effects of using antibiotic, organic acid, probiotic and prebiotic on acidity and morphology of the small intestine and tibia bone minerals and strength in broilers and laying hens. In 1st experiment 160 Ross-308 broilers in 5 treatments, 4 replicates and 8 birds in each replicate for 42 days and in 2th experiment 160 Hy- line (W36) laying hens in 5 treatments, 4 replicates and 8 hens in each replicate from 32-42 weeks of age were used in completely randomized design. At the end of each experimental period, 2 broilers and laying hens to investigate the histological of the small intestine and tibia characteristics were slaughtered. The results showed that organic acid supplementation significantly decreased pH of duodenum and jejunum in both broilers and laying hens (P