Table 4.

Effect of phytase on apparent P digestibility, bone breaking strength (BBS), and bone ash weight (AshWt) and percentage (PAsh) of nursery pigs

			GraINzyme phytase, FTU1 per kg				SEM	P-value			Sex effects
Item, kg	PC2	NC2	500	1,000	2,000	4,000		Treatment	Linear3	Quadratic3	Barrows	Gilts	SEM	P-value
Apparent P digestibility (Pdig; day 35)
Pdig, %	40.32d	33.19e	57.27c	57.24c	65.45b	72.75a	2.40	<0.0001	<0.0001	<0.0001	56.06	52.68	1.47	0.1125
Metacarpal bone parameters (day 41)
BBS, kg	44.62a	31.84c	38.96b	45.43a	43.50ab	43.98ab	1.89	<0.0001	0.0005	0.0005	41.99	40.79	1.14	0.4599
AshWt, g	1.55b	1.11d	1.40c	1.50b	1.50b	1.69a	0.03	<0.0001	<0.0001	<0.0001	1.50a	1.42b	0.02	0.0108
PAsh, %	46.38ab	40.67d	44.94c	44.78c	45.80bc	47.18a	0.44	<0.0001	<0.0001	<0.0001	44.67	45.25	0.26	0.1255

^a–eWithin a row, least square means without a common superscript differ (P < 0.05).

¹FTU = GraINzyme (Agrivida Inc., Woburn, MA) phytase units, added to NC diet.

²PC = positive control; NC = negative control (−0.15% P).

³Orthogonal contrast of adding phytase to NC diet.