Effect of citric acid and microbial phytase on ileal digestibility and serum enzyme activity in blood of broiler chickens

An experiment was conducted to study the effect of microbial phytase (MP) supplementation and citric acid (CA) on some ileal nutrients digestibility، plasma minerals retention، growth performance، serum enzyme activity and some serum metabolites of broiler chicks. Two hundred and seventy male broiler chicks (Ross 308) were used in a randomized complete block design with factorial arrangement of 3×3، three levels of CA (0، 3 and 6%) and three levels of MP (0، 500 and 1000 phytase IU/kg). The present results indicated that supplementation of diets with MP caused significant increase (P<0. 05) in body weight gain، feed intake، ileal nutrients digestibility، plasma concentration of cholesterol، triglycerides and phosphorus and also Aspartate Aminotransferase activity; however، this factor caused significant decrease (P<0. 05) in Alkaline Phosphatase، Lactate Dehydrogenase and Alanine Aminotransferase enzyme activities and plasma Fe concentration. Also، our results showed that addition of 3% CA caused significant increase (P<0. 05) in ileal digestibility of crude protein، apparent metabolizable energy and total phosphorus. Using the highest level of dietary CA decreased (P<0. 01) the growth performance parameters، ileal digestibility of nutrients (except in the case of Ca)، plasma concentration of cholesterol، P and Fe and also alkaline phosphatase enzyme activity، however this level of CA increased (P<0. 05) lactate dehydrogenase activity. In conclusion، the present findings demonstrated that administration of diets with 3% CA and 1000 U/kg MP improved ileal nutrients digestibility، minerals retention and growth performance of broiler chickens.