Influence of Citric Acid and Microbial Phytase on Growth Performance and Carcass Characteristics of Broiler Chickens

Problem statement: The aim of this study was to investigated the effects of adding citric acid and microbial phytase supplementation (Natuphos) on growth performance and carcass characteristics of broiler chickens fed corn soybean meal base diets. Approach: The experiment included nine treatments with 10 birds in each replicate using a 3×3 factorial design for two main factors of citric acid (0, 3 and 6%) and three phytase enzyme (0, 500 and 1000 IU kg). The diets were formulated based upon corn-soybean meal 7 to 21 and 22 to 42 day periods. Results: Using different levels of citric acid in diets had no effect on internal organs (except relative heart weight), whereas, diets containing 6% citric acid decreased feed intake, body weight gain and carcass yield (p<0.05) and improved feed conversion ratio and organs relative weight. Also, microbial phytase caused increase in feed intake, weight gain and relative neck weight (p<0.05). Conclusion: Depression of performance was differently affected by citric acid levels. Also, there was an additive effect between microbial phytase and citric acid.