The effects of organic acid (double-coated calcium butyrate base supplement) on performance and carcass traits of broiler chickens were assessed in three groups (PC, NC1 and NC2). The organic acid was added in three phases of feeding (1-21d, 22-35d, 36-42d) in PC, NC1 (PC deduction 40 kcal ME/kg and both methionine and lysine 1.5%) and NC2 (PC deduction 60 kcal ME/kg and both methionine and lysine 2.2%). Organic acid was added in PC with three period dosages 750-500-500 ppm and in both NC1 and NC2 1000-750-750 ppm. Addition organic acid in three controls (PC, NC1, NC2) showed similar performance of body weight gain, survival rate, feed conversion ratio and productive index, except for early starter period (1-21d of age). Broilers fed with organic acid... |