caa a22 4500 397567561 CHVBK 20180308164832.0 cr unu---uuuuu 161202e199612 xx s 000 0 eng 10.3382/ps.0751516 doi (NATIONALLICENCE)oxford-10.3382/ps.0751516 Efficacy of Supplemental Microbial Phytase at Different Dietary Calcium Levels on Growth Performance and Mineral Utilization of Broiler Chickens [Elektronische Daten] [S. SEBASTIAN, S. P. TOUCHBURN, E. R. CHAVEZ, P. C. LAGUË] A 3-wk feeding trial with 240 sexed, day-old broiler chickens was conducted to determine the efficacy of microbial phytase at different levels of dietary Ca on performance and utilization of minerals in broiler chickens fed a low-P corn-soybean diet. The experimental design was a 3 × 2 factorial arrangement of treatments; Ca at 0.6, 1.0, and 1.25% and phytase at 0 and 600 phytase U/kg diet. Phytase supplementation, regardless of Ca level, increased (P ≤ 0.005) feed intake, (P ≤ 0.0001) body weight, and (P ≤ 0.025) feed efficiency at 21 d; the optimum levels of body weight, feed intake, and feed efficiency were obtained with low (0.6%) dietary Ca plus phytase. Retentions of P, Ca, and N were increased (P ≤ 0.05) by phytase supplementation. Although the maximum retentions of P and N were obtained at the 1.0 and 1.25% Ca levels, respectively, they were not significantly different from the values obtained at 0.6% Ca. The increasing level of dietary Ca decreased plasma P (P ≤ 0.05) and Cu (P ≤ 0.06). Phytase supplementation had the opposite effect; i.e., increased plasma P (P ≤ 0.03) and Cu (P ≤ 0.02). The maximum level of plasma P was obtained with phytase at the 1.0% Ca level, but this value was not significantly different from the value obtained with phytase at the 0.6% Ca level. Phytase supplementation increased (P ≤ 0.04) the ash content of both tibia head and shaft but had no effect on mineral contents in the ash. The optimum level of ash content was observed with the 0.6% Ca diet plus phytase. The results show that microbial phytase supplementation to a low P diet improved growth performance and mineral utilization in broiler chickens. Dietary Ca levels had a significant effect on the response to phytase; the optimum growth performance and mineral utilization were achieved at the low (0.6%) level of dietary Ca supplemented with phytase. © 1996 Poultry Science Association, Inc. Metabolism and Nutrition nationallicence phytase nationallicence broiler nationallicence dietary calcium nationallicence minerals nationallicence bioavailability nationallicence SEBASTIAN S. aut TOUCHBURN S. P. 1To whom correspondence should be addressed. aut CHAVEZ E. R. aut LAGUË P. C. aut Poultry Science Oxford University Press 75/12(1996-12), 1516-1523 0032-5791 75:12<1516 1996 75 ps https://doi.org/10.3382/ps.0751516 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.3382/ps.0751516 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- SEBASTIAN S. aut NATIONALLICENCE 700 1- TOUCHBURN S. P. 1To whom correspondence should be addressed aut NATIONALLICENCE 700 1- CHAVEZ E. R. aut NATIONALLICENCE 700 1- LAGUË P. C. aut NATIONALLICENCE 773 0- Poultry Science Oxford University Press 75/12(1996-12), 1516-1523 0032-5791 75:12<1516 1996 75 ps Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford