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. 2019 Feb 7;97(4):1712–1721. doi: 10.1093/jas/skz048

Table 5.

Apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) of Ca and retention of Ca in diets containing calcium carbonate fed to sows in early-, mid-, and late-gestation periods

Item, % Phytase units/kg SEM P Period of gestation SEM P
0 500 Early Mid Late
Number of observations, n 18 24 — — 14 14 14 — —
Feed intake1, kg/d 2.73 2.65 0.19 0.242 2.46c 2.69b 2.92a 0.19 <0.001
Dry fecal excretion1, kg/d 0.27 0.25 0.02 0.312 0.24b 0.27ab 0.28a 0.02 0.039
Urinary excretion1, kg/d 8.73 5.74 1.50 0.127 9.40 6.33 5.98 1.47 0.058
ATTD of DM, % 88.94 89.38 0.53 0.571 89.18 88.98 89.33 0.48 0.794
Ca intake1, g/d 24.12 23.37 1.65 0.241 21.74c 23.70b 25.79a 1.63 <0.001
Fecal Ca output1, g/d 16.91 16.20 1.88 0.480 15.19b 19.62a 14.86b 1.94 0.001
Absorbed Ca1, g/d 7.16 7.08 0.65 0.933 6.47b 4.01b 10.87a 0.78 <0.001
ATTD of Ca, % 28.70 29.84 3.65 0.795 29.44b 17.35c 41.02a 3.80 <0.001
BEL of Ca2, mg/d 2,723 1,990 173 <0.001 2,719a 2,463b 1,888c 171 <0.001
STTD of Ca3, % 40.08 38.57 3.65 0.733 41.83a 27.72b 48.43a 3.80 <0.001
Urine Ca output1, g/d 0.38 0.33 0.09 0.444 0.55a 0.29b 0.22b 0.09 <0.001
Ca retention1, g/d 6.74 6.71 0.66 0.982 5.89b 3.68b 10.60a 0.78 <0.001
Ca retention, % of intake 27.42 28.72 3.81 0.755 27.33b 16.43c 40.46a 4.00 <0.001

a–cWithin a row, means without a common superscript differ (P < 0.05).

1All values for intake, output, or retention are the average values for the 4-d collection period.

2BEL = basal endogenous loss; the daily BEL of Ca (mg/d) was calculated by multiplying the BEL of Ca (mg/kg DMI) by the daily DMI (kg/d) of each experimental diet.

3The STTD of Ca in each diet within each period of gestation was calculated using the basal endogenous Ca loss that was specific for each period; basal endogenous losses of Ca from sows fed the Ca-free diet without microbial phytase = 1,348, 1,196, and 877 mg/kg DMI for early-, mid-, and late-gestation periods, respectively; basal endogenous losses of Ca from sows fed the Ca-free diet with microbial phytase = 1,130, 876, and 596 mg/kg DMI for early-, mid-, and late-gestation periods, respectively.