Nasibeh Mohammadagheri - Department of Animal Science, Faculty of Agriculture, Urmia University, Urmia, Iran
Ramin Najafi - Department of Animal Science, Faculty of Agriculture, Urmia University, Urmia, Iran
Gholamreza Najafi - Department of Basic Science, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran

The present experiment was conducted to evaluate the effects of organic acids and phytase enzyme supplementation on performance and intestinal histomorphology of broilers. The experiment was done in a factorial arrangement ۲ × ۲ × ۲ based on completely randomized design with eight treatments, five replicates with ۱۲ chicks in each until ۴۲ days of age. Diets included natural vinegar (۰ and ۲%), citric acid (CA; ۰.۰۰ and ۱.۰۰%) and phytase enzyme (PHY; ۰.۰۰ and ۵۰۰ FTU phytase per kg of feed). One bird from each treatment replicate was randomly selected and slaughtered to evaluate the small intestinal morphology on ۴۲ days of age. Analysis of results showed that vinegar increased feed consumption and body weight gain in total experimental period (p ˂ ۰.۰۵), while CA significantly decreased feed consumption on ۰-۱۴ days of age (p ˂ ۰.۰۵). No effect was observed on performance in interaction of organic acids together and with PHY group (p > ۰.۰۵). In duodenum CA increased the villusheight and width (p ˂ ۰.۰۵) and PHY enzyme increased villuswidth (p ˂ ۰.۰۵) and decreased crypt depth (p ˂ ۰.۰۵). On the other hand, CA along with PHY significantly decreased crypt depth (p ˂ ۰.۰۵). In jejunum PHY alone and in combination with vinegar increased the goblet cells numbers (p ˂ ۰.۰۵), whereas vinegar significantly increased the goblet cells numbers in ileum (p ˂ ۰.۰۵). The muscular thickness in duodenum, jejunum, and ileum was not affected among different treatment groups. The results showed that supplementation of organic acids and phytase together in this experiment, with no negative effects on each other, improved their effects on some parameters.

Broiler chicken, Intestinal histomorphology, Organic acids, Phytase enzyme