Determination of nutrient digestibility in corn and soybean meal using the direct and substitution methods as well as different basal diets fed to growing pigs

Figures & data

Table 1. Composition of the experimental diets used in Exp. 1 (% as-fed).

Item	Direct method	Substitution method
	Corn diet	CS-basal diet	CS-test diet
Ingredients
Corn	97.50	72.50	82.50
Soybean meal	–	25.00	15.00
Limestone	0.75	0.75	0.75
Dicalcium phosphate	0.90	0.90	0.90
Salt	0.35	0.35	0.35
Vitamin-mineral premix^a	0.50	0.50	0.50
Chemical content (analyzed value)
Dry matter	86.76	87.69	87.63
Crude protein	8.38	17.19	13.76
Starch	59.86	45.63	51.12
Ether extract	2.01	1.94	1.99
Neutral detergent fibre	7.87	9.18	7.84
Acid detergent fibre	1.68	2.96	2.13
Ash	2.86	4.13	3.64
Gross energy, MJ/kg	15.53	16.03	15.82

^aVitamin-mineral premix supplied the following nutrients per kilogram of diet: vitamin A, 5512 IU; vitamin D₃, 2200 IU; vitamin E, 30 IU; vitamin K₃, 2.2 mg; vitamin B₁₂, 27.6 μg; riboflavin, 4 mg; pantothenic acid, 14 mg; niacin, 30 mg; choline chloride, 400 mg; folic acid, 0.7 mg; thiamine, 1.5 mg; pyridoxine, 3 mg; biotin, 44 μg; Mn (MnO), 40 mg; Fe (FeSO₄·H₂O), 75 mg; Zn (ZnO), 75 mg; Cu (CuSO₄·5H₂O), 100 mg; I (KI), 0.3 mg; Se (Na₂SeO₃), 0.3 mg.

Table 2. Composition of the experimental diets used in Exp. 2 (% as-fed).

Item	Basal diet 1	Test diet 1	Basal diet 2	Test diet 2
Ingredients
Corn	97.50	82.50	72.50	58.00
Soybean meal	–	15.00	25.00	39.50
Limestone	0.75	0.75	0.75	0.75
Dicalcium phosphate	0.90	0.90	0.90	0.90
Salt	0.35	0.35	0.35	0.35
Vitamin-mineral premix^a	0.50	0.50	0.50	0.50
Chemical content (analyzed value)
Dry matter	86.76	87.63	87.69	87.16
Crude protein	8.38	13.76	17.19	22.26
Starch	59.86	51.12	45.63	37.27
Ether extract	2.01	1.99	1.94	2.41
Neutral detergent fibre	7.87	7.84	9.18	8.85
Acid detergent fibre	1.68	2.13	2.96	3.37
Ash	2.86	3.64	4.13	4.90
Gross energy, MJ/kg	15.53	15.82	16.03	16.12

^aVitamin-mineral premix supplied the following nutrients per kilogram of diet: vitamin A, 5512 IU; vitamin D₃, 2200 IU; vitamin E, 30 IU; vitamin K₃, 2.2 mg; vitamin B₁₂, 27.6 μg; riboflavin, 4 mg; pantothenic acid, 14 mg; niacin, 30 mg; choline chloride, 400 mg; folic acid, 0.7 mg; thiamine, 1.5 mg; pyridoxine, 3 mg; biotin, 44 μg; Mn (MnO), 40 mg; Fe (FeSO₄·H₂O), 75 mg; Zn (ZnO), 75 mg; Cu (CuSO₄·5H₂O), 100 mg; I (KI), 0.3 mg; Se (Na₂SeO₃), 0.3 mg.

Table 3. Chemical composition of corn and soybean meal used in Exp. 1 and 2 (as-fed basis, %)^a.

	Corn	Soybean meal
Dry matter	86.62	88.69
Crude protein	8.31	45.01
Starch	61.03	3.74
Ether extract	2.16	1.54
Neutral detergent fibre	7.21	11.38
Acid detergent fibre	1.58	6.08
Ash	1.06	5.84
Gross energy, MJ/kg	16.02	17.33

^aAll data are the results of a chemical analysis conducted in duplicate.

Table 4. Effects of the direct and substitution methods on the apparent total tract digestibility of nutrients (%) in diets fed to growing pigs (Exp. 1)^c.

	Direct method	Substitution method		SEM	p value
	Corn diet	CS-basal diet	CS-test diet
Dry matter	90.86	91.15	91.30	0.19	0.67
Gross energy	91.31	91.40	91.28	0.20	0.29
Crude protein	87.97^b	90.60^a	89.56^a	0.30	<0.01
Organic matter	92.26	92.63	92.68	0.17	0.63

^a,bMeans in the same row with different superscripts differ (P ≤ .05).

^cData are means of 6 observations.

Table 5. Effects of the direct and substitution methods on the apparent total tract digestibility of nutrients (%) in corn fed to growing pigs (Exp. 1)^a.

	Direct method	Substitution method	SEM	p value
Dry matter	93.19	92.13	0.41	0.29
Gross energy	90.01	88.76	0.53	0.26
Crude protein	88.17	88.70	0.55	0.76
Organic matter	94.62	93.27	0.37	0.16

^aData are means of 6 observations.

Table 6. Effects of different basal diets on the apparent total tract digestibility of nutrients (%) in diets fed to growing pigs (Exp. 2)^c.

	Basal diet 1	Test diet 1	Basal diet 2	Test diet 2	SEM	p value
Dry matter	90.86	91.30	91.15	91.38	0.18	0.70
Gross energy	91.31	91.28	91.39	91.81	0.19	0.11
Crude protein	87.97^b	89.55^a	90.60^a	91.45^a	0.26	<0.01
Organic matter	92.26	92.68	92.63	92.92	0.16	0.52

^a,bMeans in the same row with different superscripts differ (P ≤ .05).

^cData are means of 6 observations.

Table 7. Effects of different basal diets on the apparent total tract digestibility of nutrients (%) in soybean meal fed to growing pigs (Exp. 2)^c.

	Corn-basal diet	Corn-SBM basal diet	SEM	p value
Dry matter	93.79	92.30	0.70	0.63
Gross energy	91.81^a	88.86^b	0.55	0.04
Crude protein	98.50^a	93.49^b	0.29	0.04
Organic matter	95.06	94.08	0.51	0.82

^a,bMeans in the same row with different superscripts differ (P ≤ .05).

^cData are means of 6 observations.