Table 4.

Phosphorus (P), calcium (Ca), and nitrogen (N) balance of growing pigs¹

Ca source	Ca formate		Ca carbonate
Exogenous phytase, FTU/kg of diet	0	1,500	0	1,500	1,500
Formic acid, g/kg of diet	0	0	0	0	8.0	P-value
Item	Diet 1	Diet 2	Diet 3	Diet 4	Diet 5	SEM	Diet 4 vs. 5	Ca source	Phytase	Ca source × Phytase
P
Intake, g/d	6.0	6.0	6.0	6.1	6.0	0.75
In feces, g/d	4.6	2.6	4.3	2.5	2.2	0.33	0.019	0.182	<0.001	0.834
In urine, mg/d	8.2	31.3	20.3	69.9	132.3	36.95	0.251	0.357	0.005	0.254
Retention, g/d	1.4	3.4	1.7	3.5	3.7	0.45	0.268	0.094	<0.001	0.441
Ca
Intake, g/d	7.4	7.4	8.0	8.1	8.0	0.95
In feces, g/d	3.8	2.1	4.3	2.9	2.6	0.30	0.112	<0.001	<0.001	0.105
In urine, g/d	1.6	0.6	1.2	0.7	0.4	0.16	0.027	0.294	<0.001	0.193
Retention, g/d	2.1	4.6	2.5	4.5	5.0	0.64	0.063	0.512	<0.001	0.220
N
Intake, g/d	44.1	44.1	44.1	44.3	44.0	5.49
In feces, g/d	7.2	6.7	7.1	7.4	6.7	0.72	0.178	0.201	0.493	0.124
In urine, g/d	14.9	15.7	14.2	16.3	16.1	2.51	0.345	0.644	0.066	0.424
Urea, % of total urine N	83.7	82.5	84.2	81.2	82.8	1.02	0.158	0.651	0.006	0.190
Retention, g/d	22.0	21.6	22.7	20.6	21.3	2.55	0.388	0.898	0.078	0.372

¹Least square means based on 8 observations per diet.