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. 2020 Aug 12;99(11):5792–5801. doi: 10.1016/j.psj.2020.06.082

Table 6.

Effect of dietary Ca, available P levels, and phytase on bone densitometry of total, trabecular space, and cortical bone tissues in femur proximal metaphysis and mid-diaphysis of single-comb White Leghorn hens at 78 wk of age.1,2

Bone mineral density (mg/cm3)
 Bone cross-sectional area (mm2)
 Bone mineral content (mg/mm)3
Total Cortical Trabecular space4 Total Cortical Trabecular space4 Total Cortical Trabecular space4
Proximal metaphysis5
 PC 519a 1,075 259a 47.2 14.8 30.1 24.5a 15.8 7.74a
 NC1 475b,c 1,077 220c 47.8 14.1 32.9 22.7c 15.2 7.20a,b
 NC2 456c 1,086 190d 47.2 14.1 32.4 21.5c 15.2 6.06c
 NC1 + BSP 519a 1,087 253a,b 46.7 14.7 30.4 24.2a,b 16.0 7.62a,b
 NC2 + BSP 498a,b 1,087 230b,c 46.1 14.3 30.2 23.0b,c 15.5 6.89b,c
 Pooled SEM 11.7 6.7 10.2 0.53 0.34 0.86 0.55 0.34 0.311
P-value
 Diet 0.002 0.543 0.002 0.234 0.389 0.083 0.002 0.391 0.003
 Co-variate (BW)6 0.017 0.190 0.112 0.002 0.002 0.910 <0.001 <0.001 0.135
Mid-diaphysis5
 PC 572a 1,162 254a 39.9 13.7 24.3 22.8a 15.9 6.11a,b
 NC1 533b,c 1,169 211b,c 39.9 13.4 26.1 21.2b 15.6 5.46b
 NC2 516c 1,162 181c 39.9 13.7 25.7 20.6b 15.9 4.58c
 NC1 + BSP 584a 1,164 263a 39.6 14.1 24.3 23.1a 16.4 6.32a
 NC2 + BSP 560a,b 1,162 235a,b 38.8 13.6 23.7 21.7a,b 15.8 5.39b,c
 Pooled SEM 12.7 8.4 11.1 0.53 0.37 0.94 0.51 0.36 0.303
P-value
 Diet 0.004 0.966 <0.001 0.540 0.715 0.385 0.008 0.653 0.002
 Co-variate (BW)6 0.008 0.346 0.209 0.008 <0.001 0.459 <0.001 <0.001 0.485

a–dTreatment means with no common superscript within each column at the proximal metaphysis and mid-diaphysis differ significantly (P ≤ 0.05).

1

Each dietary treatment mean was calculated from 20 hens at each age.

2

PC, 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.

3

Calculated by multiplying the respective bone cross-sectional area by bone mineral density to yield the amount of mineral (mg) contained in 1-mm-thick X-ray scan.

4

Represents both trabecular and medullary bone tissues within the trabecular space.

5

Femur proximal metaphysis measurement at 30% of the bone length from the proximal end and mid-diaphysis measurement at the longitudinal center of the bone.

6

Co-variate effect was only considered in the analysis when P ≤ 0.05.