Table 2.

Effect of dietary Ca, available P levels, and phytase on % hen-day egg production of single-comb White Leghorn hens from 68 to 78 wk of age.^1,2

Weeks of age	Pre-experimental period	Experimental period
	-----------------------------------------%---------------------------------------
	66–68	69	70	71	72	73	74	75	76	77	78
PC	91.4	86.4	87.1	89.3	92.9a	87.9a	93.6a	89.3a	92.1a	90.0a,b	91.0a
NC1	92.9	93.6	87.1	91.4	87.9a	87.1a	86.4a	89.5a	91.4a	84.3b	85.0a
NC2	96.4	90.7	82.1	85.7	76.4b	72.1b	71.4b	72.2b	69.3b	69.3c	73.3b
NC1 + BSP	96.4	93.6	92.1	90.7	91.4a	90.0a	92.5a	88.7a	85.7a	95.7a	89.0a
NC2 + BSP	92.9	92.1	93.6	87.9	87.9a	89.3a	85.7a	87.9a	90.0a	82.1b	86.0a
Pooled SEM	1.97	-----------------------------------4.00-----------------------------
P-value
Diet	0.258
Diet × Age		----------------------------------<0.001---------------------------

^a–cTreatment means with no common superscript within each column differ significantly (P ≤ 0.05).

¹Treatment means at each week of age were calculated with 20 replicates per treatment.

²PC, positive control (nutrient-adequate diet with 3.5% Ca and 0.35% available P), NC1, negative control 1 (the PC reduced in Ca and available P by 0.187 and 0.159% of the diet, respectively); NC2, negative control 2 (the PC reduced in Ca and available P by 0.231 and 0.275% of the diet, respectively); and NC1 + BSP and NC2 + BSP, the NC diets supplemented with Buttiauxella sp. phytase at 600 FTU/kg.