Table 4.

The eggshell and egg qualityof laying hens. Data are presented as means (SD)^a

NPP,%	LPS	Shell weight/ egg weight, %	Eggshell strength, kg/cm2	Yolk color	Ca of eggshell, %	P of eggshell,%	Eggshell color	Eggshell thickness, mm	Haugh units	Albumen height, mm
0.12	–	11.93	3.81	6.40b	35.13	0.199	63.43c	0.322	77.82	6.17
	+	10.63	3.56	5.73d	35.24	0.205	64.44bc	0.342	82.57	6.84
0.40	–	11.54	3.88	6.77c	34.45	0.208	65.40b	0.329	77.82	6.23
	+	11.54	4.30	7.70b	35.08	0.201	63.38c	0.332	85.35	7.27
SEM		0.34	0.08	0.12	0.14	0.003	0.30	0.002	0.72	0.10
Main effect means
NPP
0.12		11.28	3.69	6.07c	35.19	0.202	63.92	0.332	80.24	6.51
0.40		11.54	4.08	7.23b	34.77	0.204	64.41	0.330	81.52	6.74
LPS
–		11.74	3.85	6.58	34.79	0.204	64.41	0.326c	77.82c	6.20c
+		11.08	3.93	6.72	35.17	0.203	63.91	0.337b	83.94b	7.05b
P-value
NPP		0.070	0.740	<0.001	0.261	0.808	0.445	0.695	0.294	0.206
LPS		0.187	0.082	0.490	0.381	0.935	0.401	0.016	<0.001	<0.001
NPP × LPS		0.151	0.586	<0.001	0.490	0.349	0.012	0.089	0.293	0.339

^aMeans were calculated on n = 5 replicates (6 eggs per replicate) per treatment

^b-dWithin comparisons, means in a column with no common superscripts differ significantly (P < 0.05)