Table 3. Physical, mechanical and geometric properties of tibia obtained from 42-day-old broilers in control groups and supplemented with organic Zn in 25% of recommended dose with or without phytase inclusion.

Item		Group				Pooled SEM	P-value
		NC (n = 10)	Zn25% (n = 10)	Zn25%+phyt (n = 10)	PC (n = 10)
		Bone general properties
Bone weight, g		22.8	21.1	25.1	23.5	0.8	ns
Bone length, mm		111	112	111	111	1	ns
Bone weight/bone length, g·mm-1		0.199ab	0.184a	0.224bc	0.235c	0.007	<0.001
Bone weight/body weight, %		1.12	1.04	1.02	0.94	0.05	ns
		Bone geometrical properties
Horizontal internal diameter, mm		4.67a	5.81b	5.91b	5.68b	0.17	<0.001
Horizontal external diameter, mm		8.32a	9.49b	10.47c	9.82bc	0.28	<0.001
Vertical internal diameter, mm		4.29a	4.90b	5.29b	4.89b	0.14	<0.001
Vertical external diameter, mm		6.32a	8.12b	9.14c	8.24b	0.29	<0.001
Cross section area, mm2		26.3a	38.0b	50.5c	42.3bc	2.7	<0.001
Mean relative wall thickness,		0.67	0.65	0.75	0.71	0.03	ns
Cortical index, %		38.9a	38.9a	42.9b	41.2ab	0.75	0.009
Vertical cortical index, %		32.1a	39.7b	42.1b	40.4b	1.3	<0.001
Vertical wall thickness, mm		1.01a	1.61b	1.92c	1.67bc	0.09	<0.001
Midshaft volume, cm3		1.17a	1.71b	2.22c	1.69b	0.12	<0.001
Moment of inertia, mm4		86.4a	214.2b	358.3c	256.7b	30.6	<0.001
Index of gyration, mm		1.81a	2.38b	2.63c	2.38b	0.09	<0.001
		Bone mechanical properties
Yield strength, N		163a	357c	293b	197a	21	<0.001
Ultimate strength, N		240a	441b	464b	289a	25	<0.001
Elastic stress, MPa		68.7b	75.6b	44.3a	33.6a	4.8	<0.001
Ultimate stress, MPa		100.9b	93.5b	71.0a	51.1a	6.0	0.001
Bending moment, N·m		1.81a	3.99c	3.27b	1.97a	0.25	<0.001

^{a, b, c}–mean values in rows with different letters differ significantly at P<0.05; Data given are LSMeans; SEM–standard error of the mean

The description of the groups as in Table 1.