Determining the Phosphorus Release for Natuphos E 5,000 G Phytase for Nursery Pigs

A total of 286 pigs (PIC 327×1050; initially 11.1 ± 0.1 kg, and d 42 of age) were used in a 21-d growth trial to determine the available P (aP) release curve for a novel phytase source (Natuphos E 5,000 G, BASF Corporation, Florham Park, NJ). Pigs were randomly allotted to pens at weaning. On d 0 of the experiment (d 18 after weaning), pens were allotted in a randomized complete block design to 1 of 8 treatments. There were 4 pigs/pen and 9 pens/treatment. Pigs were fed a corn-soybean meal-based diet formulated to 1.25% standardized ileal digestible Lys. Experimental diets were formulated to contain 0.64% Ca and increasing aP supplied by either monocalcium P (0.12, 0.18, and 0.24% aP) or from increasing phytase (150, 250, 500, 750, and 1,000 FTU/kg) added to the 0.12% aP diet. Diets were analyzed for phytase using the AOAC method and analyzed concentrations were 263, 397, 618, 1,100, and 1,350 FTU/kg, respectively. On d 21 of the study, 1 pig per pen was euthanized and the right fibula was collected for bone ash and percentage bone ash calculations. From d 0 to 21, increasing P from monocalcium P or increasing phytase improved (linear, P<0.01) ADG and G:F. Bone ash weight and percentage bone ash increased (linear, P<0.01) with increasing monocalcium P or phytase. When formulated phytase values and percentage bone ash are used as the response variables, aP release for up to 1,000 FTU/kg of Natuphos E 5,000 G phytase can be predicted by the equation: aP release = 0.000212 × FTU/kg phytase.

	Inorganic P, % aP				Phytase, FTU/kg
Item	0.12	0.18	0.24	150		250	500	750	1,000	SEM
BW, kg
d 0	11.2	11.1	11.1	11.0		11.1	11.1	11.2	11.2	0.19
d 211,4	20.4	22.3	23.3	21.3		21.6	21.7	22.6	23.3	0.38
d 0 to 21
ADG, g1,4	436	537	583	487		495	504	544	576	13.3
ADFI, g1,4	860	936	981	916		902	897	968	971	21.3
G:F, g/kg1,2,4	505	573	595	532		546	561	560	592	9.4
Bone ash weight, g3,4	0.680	0.850	0.855	0.713		0.667	0.772	0.821	0.941	0.044
Bone ash, %3,4	38.2	41.2	42.0	38.7		39.6	41.2	43.1	45.5	0.99
1Inorganic linear: P<0.001; 2Inorganic quadratic: P<0.05; 3Inorganic linear: P<0.05; 4Phytase linear: P<0.001