Table 3.

Effects of dietary Ca and NPP levels on serum Ca, P, and 25-OHD₃ contents and ALP activity of broilers¹.

Ca levels, %	1.00		0.35		SEM	Ca level3, %		SEM	NPP level3, %		SEM	P-value
NPP levels, %	0.452	0.232	0.452	0.232		1.00	0.35		0.45	0.23		Ca	NPP	Ca × NPP
Day 7
Serum Ca, mmol/L	1.79c	2.19a	2.06b	1.94b	0.04	1.99	2.00	0.03	1.93	2.07	0.03	0.79	0.003	＜0.0001
Serum P, mmol/L	1.90a	0.96c	1.41b	1.89a	0.08	1.43	1.65	0.05	1.66	1.42	0.05	0.009	0.006	＜0.0001
Serum ALP, U/L	207	291	149	183	30	249a	166b	21.5	178	237	21.5	0.012	0.06	0.42
Serum 25-OHD3, ng/mL	24.4a	18.4c	23.5a	20.6b	0.7	21.4	22.1	0.49	24.0	19.5	0.49	0.31	＜0.0001	0.03
Day 14
Serum Ca, mmol/L	2.03b	2.58a	2.29a,b	2.17b	0.11	2.31	2.23	0.08	2.16	2.38	0.08	0.49	0.07	0.006
Serum P, mmol/L	1.78	1.83	1.34	1.44	0.08	1.80a	1.39b	0.06	1.56	1.64	0.06	＜0.0001	0.38	0.76
Serum ALP, U/L	186	227	106	92	15.0	206a	99.2b	10.6	146	159	10.6	＜0.0001	0.38	0.08
Serum 25-OHD3, ng/mL	34.1a	29.4c	30.9b,c	32.1a,b	0.77	31.7	31.5	0.54	32.5	30.7	0.54	0.73	0.03	0.0008
Day 21
Serum Ca, mmol/L	1.78c	2.26a	2.01b	1.86c	0.03	2.04	1.94	0.02	1.91	2.06	0.02	0.009	＜0.0001	＜0.0001
Serum P, mmol/L	1.90a	1.22c	1.30c	1.62b	0.04	1.56	1.45	0.03	1.6	1.4	0.03	0.03	0.0005	＜0.0001
Serum ALP, U/L	148	192	69	54	25	170a	61.6b	17.5	108	123	17.5	0.0002	0.56	0.25
Serum 25-OHD3, ng/mL	33.4a,b	29.4b	32.4a,b	35.7a	1.4	31.4	34.0	1.01	32.9	32.5	1.01	0.08	0.78	0.017

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

¹Abbreviations: 25-OHD₃, 25-hydroxyvitamin D₃; ALP, alkaline phosphatase; NPP, nonphytate P.

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

³Data represented the means of 12 replicate cages (n = 14).