. 2020 Nov 19;100(2):900–909. doi: 10.1016/j.psj.2020.10.075

Table 9.

Effect of presence of phytate on standardized ileal digestibility (SID) and digestible Ca and P as affected by limestone particle size (mean ± SE).

TRT	n	LM GMD¹ μm	Phytate		SID, %²		Digestible, %³
TRT	n	LM GMD¹ μm	Source	%	Ca	P	Ca	P
2	14	800	Corn	0.234	43.00 ± 0.861	24.03 ± 0.761^b	0.333 ± 0.007	0.077 ± 0.002^b
3	8	151	Corn	0.234	33.56 ± 1.139	14.08 ± 1.007^c	0.261 ± 0.009	0.044 ± 0.003^c
11	7	800	None	0	84.31 ± 1.218	91.42 ± 1.077^a	0.662 ± 0.009	0.285 ± 0.003^a
12	7	151	None	0	72.89 ± 1.218	91.84 ± 1.077^a	0.573 ± 0.009	0.286 ± 0.003^a
Main effects
Phytate			0%		78.59 ± 0.861		0.618 ± 0.007
			0.234%		38.28 ± 0.714		0.297 ± 0.006
LM GMD, μm			151		53.23 ± 0.834		0.417 ± 0.007
			800		63.64 ± 0.746		0.498 ± 0.006
P-values
LM GMD					<0.001	<0.001	<0.001	<0.001
Phytate					<0.001	<0.001	<0.001	<0.001
LM GMD × phytate					0.386	<0.001	0.323	<0.001

^a-dMeans within a column with different superscript letters differ (P < 0.05) based on Tukey HDS means separation. Main effects are shown and compared only when the interaction was not significant.

LM, limestone; GMD, geometric mean diameter. Limestone is the same limestone source with different particle sizes. Ca source was added to provide 0.7% Ca in the final diet.

Standardized ileal Ca or P digestibilities. The non-diet related endogenous Ca and P losses was determined with 6 pens in this experiment and used for determining standardized from apparent digestibilities and were 105.6 and 190.8 mg per kg DM intake, respectively.

Digestible Ca and P determined by multiplying analyzed Ca or P in the diets by the digestibility of that nutrient.