Growth performance and nutrient utilization of broiler chickens fed diets supplemented with phytase alone or in combination with citric acid and multicarbohydrase
2010
Woyengo, T.A. | Slominski, B.A. | Jones, R.O.
An experiment was conducted to determine the effect of supplementing a corn-soybean meal-based diet with phytase alone or in combination with citric acid (CA) or multicarbohydrase, a preparation containing nonstarch polysaccharide-degrading enzymes, or both, on growth performance, nutrient utilization, and bone mineralization. A total of 360 one-day-old broiler chicks were assigned to 6 dietary treatments, consisting of 12 pens of 5 birds each, and were fed experimental diets from 1 to 21 d of age. The diets included a positive control (0.46% nonphytate P; 1.1% Ca) and a negative control (NC; 0.26% nonphytate P; 0.89% Ca) without or with phytase (600 U/kg) alone, phytase plus CA (5 g/kg), phytase plus multicarbohydrase (Superzyme OM; 0.6 g/kg), or phytase (Ronozyme P-CT) plus CA and multicarbohydrase. Birds fed the positive control diet had higher (P < 0.05) BW gain (764 vs. 594 g/21 d) and tibia ash content (50.0 vs. 38.3%) than those fed the NC diet. Phytase improved (P < 0.05) BW gain (632 g/21 d), which increased further (P < 0.05) to 673 g/21 d for the phytase plus multicarbohydrase diet. In contrast to phytase alone, phytase plus multicarbohydrase supplementation improved (P < 0.05) feed conversion ratio of the NC diet from 1.37 to 1.32. Tibia ash content for the NC diet increased (P < 0.05) from 38.3 to 42.4% due to phytase addition. Phytase improved (P < 0.05) ileal digestibility of P from 29.5 to 43%, and the addition of CA or multicarbohydrase, or both, to a phytase-supplemented diet further increased (P < 0.05) P digestibility to 51.5, 53.4, and 54.3%, respectively. Phytase addition improved (P < 0.05) diet AMEn content from 2,959 to 3,068 kcal/kg, which tended (P < 0.06) to increase further with CA (3,150 kcal/kg) or multicarbohydrase (3,142 kcal/kg) addition. No beneficial interactions were detected between CA and multicarbohydrase for all response criteria measured. Results show that addition of multicarbohydrase to the phytase-supplemented broiler diets improved nutrient utilization and growth performance.
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