Effect of citric acid and microbial phytase enzyme on ileal digestibility of some nutrients in broiler chicks fed corn-soybean meal diets

Abstract

A total of 270 Ross 308 male broilers were used in a randomized complete block design for a period of five weeks. The experiment included nine treatments, three replicates with 10 birds in each replicate of 3×3 factorial design. Two main factors of citric acid (CA) (0, 3 and 6%) and a microbial phytase (MP) (0, 500 and 1000 IU/kg) were used. The results indicated that diets containing 3% CA caused significant increase in P content in tibia ash, ileal digestibility of crude protein, apparent metabolizable energy, total phosphorus and body weight (P<0.01). Addition of 6% CA to diets compared with diets without acid and the diets having 3% CA, significantly decreased (P<0.01) body weight, average daily gain, average daily feed intake, Ca content in tibia ash, ileal digestibility of crude protein, apparent metabolizable energy and total phosphorus. Also, 6% CA diet caused significant increase in measured GI-tract organs (P<0.05). The different levels of MP significantly increased ileal digestibility of nutrients, tibia ash, Ca and Mg contents in tibia ash (P<0.01), but had no significant effect on measured GI-tract organs. The diets having 1000 unit of MP caused a significant improvement on performance factors (P<0.05) and P content in tibia ash (P<0.01). These results demonstrated that addition of MP and 3% CA to the diet caused improvement in ileal nutrients digestibility, growth performance and increased minerals retention of broiler chickens.