Table 7.

Standardized ileal digestibility of CP and AA in corn, wheat, and wheat middlings calculated using the direct or the difference procedure¹

Item, %	Direct procedure			Difference procedure			Pooled SEM	P-value
	Corn	Wheat	Wheat middlings	Corn	Wheat	Wheat middlings		Ingredient	Procedure	Ingredient × procedure
CP	88.6	79.9	61.7	85.3	77.7	69.5	2.94	<0.001	0.761	0.119
Indispensable AA
Arg	93.3	80.6	79.8	89.4	80.9	77.9	2.21	<0.001	0.349	0.633
His	90.5	81.4	77.0	87.5	80.9	76.3	2.11	<0.001	0.641	0.806
Ile	90.0	80.9	70.6	87.8	78.4	72.7	2.87	<0.001	0.908	0.678
Leu	91.7	82.8	73.8	91.1	80.5	74.6	2.45	<0.001	0.924	0.825
Lys	83.8	68.9	61.4	82.1	66.9	66.4	3.65	<0.001	0.882	0.522
Met	91.9	84.0	74.5	93.9	82.9	78.0	2.15	<0.001	0.302	0.446
Phe	90.7	84.1	74.3	89.9	82.6	75.1	2.45	<0.001	0.738	0.893
Thr	85.5	76.6	63.0	83.9	72.1	67.4	3.47	<0.001	0.964	0.440
Trp	84.2	82.0	73.1	67.9	76.8	51.8	3.56	<0.001	<0.001	0.087
Val	87.6	78.7	68.3	86.3	75.6	71.00	2.71	<0.001	0.995	0.556
Dispensable AA
Ala	91.2	74.0	63.7	90.0	72.4	69.7	2.62	<0.001	0.630	0.270
Asp	89.4	74.4	69.9	83.6	68.4	67.6	3.87	<0.001	0.208	0.862
Cys	85.9	83.6	74.6	82.9	78.3	71.9	2.45	0.001	0.182	0.847
Glu	92.9	91.8	83.5	86.4	89.9	80.5	2.35	0.001	0.097	0.585
Gly	92.5	82.5	63.3	75.5	79.4	67.9	4.87	0.001	0.206	0.087
Pro	121.6	117.1	126.9	113.6	115.6	114.0	5.45	0.622	0.045	0.421
Ser	90.4	84.4	73.1	86.3	80.3	70.8	2.80	<0.001	0.206	0.925

¹Values are means for 7 or 8 observations per treatment.