Table 2.

Effects of dietary Ca and NPP levels on tibia BMD, BBS, and ash content of broilers¹.

Ca levels, %	1.00		0.35		SEM	P-value
NPP levels, %	0.452	0.232	0.452	0.232		Ca × NPP
Day 7
Tibia BMD, g/cm2	0.094a	0.043d	0.072b	0.067c	0.001	＜0.0001
Tibia BBS, kg	3.77a	0.63d	2.33b	1.90c	0.09	＜0.0001
Tibia ash content, %	47.9a	27.3c	40.3b	38.9b	0.7	＜0.0001
Day 14
Tibia BMD, g/cm2	0.160a	0.068d	0.101b	0.096c	0.001	＜0.0001
Tibia BBS, kg	10.5a	1.19d	4.99b	3.55c	0.28	＜0.0001
Tibia ash content, %	50.4a	30.1d	40.5b	39.1c	0.5	＜0.0001
Day 21
Tibia BMD, g/cm2	0.201a	0.098c	0.124b	0.130b	0.004	＜0.0001
Tibia BBS, kg	18.9a	3.08c	8.04b	8.87b	0.50	＜0.0001
Tibia ash content, %	50.1a	33.8c	40.0b	40.9b	0.7	＜0.0001

^a-dMeans within a row lacking a common superscript differ (P < 0.05).

¹Abbreviations:BMD, bone mineral density; BBS, bone breaking strength; NPP, nonphytate P.

²Data represented the means of 7 replicate cages (n = 7).