Effects of sodium gluconate and phytase on performance and bone characteristics in broiler chickers

An experiment was conducted to evaluate the effects of corn soybean meal diets with added sodium gluconate (0 and 20 g/kg) and phytase (0, 500 and 1000 U/kg) on performance and bone characteristics of broiler chicks. A total of 350 eight-day-old Arbor Acre male chicks were used with a 2 × 3 plus 1 factorial arrangement. A positive control diet, adequate in non-phytate-phosphorus and calcium without sodium gluconate and phytase, was used. Chickens were randomly allocated to seven treatments with each treatment having five replicates. The experiment lasted from 8 to 42 d posthatching. The outcomes of the study indicated that the low-non-phytate-phosphorus diet caused a negative effect (P<0.05) on the average daily gain, average daily feed intake, tibia weight and tibia ash of birds compared to the positive control diet. The supplementation of 20 g sodium gluconate/kg increased average daily gain during days 22–42 (P=0.005), 8–42 (P=0.013) and tibia ash at 21 d (P=0.002). Phytase addition improved (P<0.05) average daily gain and average daily feed intake during the whole experiment and tibia weight, tibia ash at 21 and 42 d and calcium content in tibia ash at 42 d. Compared with diets supplemented with 500 U phytase/kg, diets supplemented with 1000 U phytase/kg had significantly higher average daily feed intake during the whole experiment and average daily gain during days 22–42 and 8–42 and tibia ash at days 21 and 42. There was a significant interaction between sodium gluconate and phytase for average daily gain (P=0.027) from 8 to 21 d and tibia weight (P=0.020) at 42 d. These results demonstrated that sodium gluconate and phytase supplementation to low-phosphorus diets improved performance and phytate-phosphorus utilization by chicks during the whole growing periods.