Table 4.

Effects of increasing aP from inorganic P or GraINzyme phytase on nursery pig growth performance and bone ash values¹,²

	Inorganic P, % aP3			Phytase, FTU/kg4						Inorganic P, P-value		Phytase, P-value
Item	0.11	0.19	0.27	150	250	500	1,000	1,500	SEM	Linear	Quadratic	Linear	Quadratic
BW, kg
Day 0	10.1	10.1	9.8	9.7	9.9	10.1	9.7	10.1	0.19	0.087	0.257	0.229	0.021
Day 21	18.7	19.8	20.4	18.9	19.0	19.5	20.0	20.5	0.36	<0.001	0.334	<0.001	0.561
Days 0 to 21
ADG, g	412	465	504	436	434	448	489	491	10.7	<0.001	0.527	<0.001	0.103
ADFI, g	686	739	746	707	717	719	739	757	15.9	0.002	0.151	0.001	0.514
G:F, g/kg	600	630	675	617	606	622	661	649	7.5	<0.001	0.404	<0.001	0.049
Bone characteristics5
Bone ash, g	0.614	0.764	0.812	0.601	0.623	0.672	0.722	0.861	0.0284	<0.001	0.141	<0.001	0.162
Bone ash, %	39.7	43.8	45.4	39.0	41.7	43.0	41.3	44.2	0.01	0.001	0.364	0.003	0.665

¹A total of 360 nursery pigs (Line 200 × 400, DNA, Columbus, NE; initially 9.9 kg body weight (BW)) were used in a 21-d growth trial to determine the available P (aP) release curve for GraINzyme phytase. There were five pigs per pen and nine replications per treatment.

²ADG = average daily gain; ADFI = average daily feed intake; G:F = gain-to-feed ratio.

³Inorganic P was added to the diet by increasing monocalcium P.

⁴GraINzyme, Agrivida, Woburn, MA.

⁵One pig per pen (nine pens per treatment) was euthanized on day 21, and the right fibula was collected to determine bone ash weight and percentage bone ash. Fibulas were autoclaved for 1 hr. After cleaning, bones were placed in a drying oven at 105 °C for 7 d and then ashed in a muffle furnace at 600 °C for 24 h.