Table 3.

Effect of method, protein source and basal diet on the apparent total tract digestibility (AID, %) of nitrogen, organic matter and dry matter of the experimental diets¹.

Item	Wheat	Cottonseed meal		Soybean meal		SED	Significance2
		Simple	Wheat	Simple	Wheat
Nitrogen
Chromic oxide	72.5	59.3	64.5	86.2	83.4	1.18	Prot. (<0.001); BD (0.034); Prot. × BD (<0.001)
Acid-insoluble ash	77.4	62.4	71.1	85.8	82.2		Prot. × BD × M (<0.001)
Total faecal collection	77.5	61.4	72.5	85.9	82.6
Organic matter
Chromic oxide	79.9	78.1	62.1	92.9	84.2	1.02	Prot. (<0.001); BD (<0.001)
Acid-insoluble ash	83.8	79.7	71.3	93.2	83.7		Prot. × BD × M (<0.001)
Total faecal collection	84.9	78.1	72.7	93.7	85.0
Dry matter
Chromic oxide	71.9	73.6	58.2	89.0	80.6	1.17	Prot. (<0.001); BD (<0.001)
Acid-insoluble ash	81.1	76.7	68.8	89.6	80.2		Prot. × BD × M (<0.001)
Total faecal collection	82.2	73.5	68.6	89.1	81.6

SED = standard error of difference.

¹The basal diet was either a 1:1 sugar and starch mix (Simple) or pure wheat (Wheat); protein sources were either 400 g/kg cottonseed meal or soybean meal mixed with the basal diet or diet containing 926 g/kg wheat. n = 5 for each diet.

²Significance of effects of pure wheat (926 g/kg) vs. other diets, protein source (Prot.), Basal diet (BD) or measurement method (M) and interactions have been included in parentheses.