Table 1. Composition of the experimental diets (%, as-fed basis)

Ingredient (%)	Diets1)
	3200	3100	3000	2900	2800	2700
Corn	42.55	38.04	33.53	29.02	24.51	20.00
Wheat HRW	24.00	22.20	20.40	18.60	16.80	15.00
Wheat bran	-	4.90	9.80	14.70	19.60	24.50
SBM (48%)	30.00	29.20	28.40	27.60	26.80	26.00
Oats	-	2.00	4.00	6.00	8.00	10.00
Vegetable oil	0.20	0.41	0.62	0.83	1.04	1.25
Limestone	1.00	1.00	1.00	1.00	1.00	1.00
Monocal phos Biofos	1.50	1.50	1.50	1.50	1.50	1.50
Salt	0.30	0.30	0.30	0.30	0.30	0.30
Vitamin premix2)	0.30	0.30	0.30	0.30	0.30	0.30
DL-methionine	0.15	0.15	0.15	0.15	0.15	0.15
Calculated composition
ME (kcal/kg)	3,203.0	3,103.2	3,003.4	2,903.6	2,803.8	2,704.0
CP (%)	21.11	21.11	21.11	21.12	21.12	21.12
Lys (%)	1.11	1.11	1.10	1.10	1.09	1.09
Met + Cys (%)	0.85	0.85	0.85	0.86	0.86	0.86

Teatment number indicate dietary AME (kcal/kg).
Vitamin and mineral pre-mixture provided the following nutrients per kg of diet: vitamin A, 24,000 IU; vitamin D₃, 6,000 IU; vitamin E, 30 IU; vitamin K, 4 mg; thiamine, 4 mg; riboflavin, 12 mg; pyridoxine, 4 mg; folacine, 2 mg; biotin, 0.03 mg; vitamin B₈ 0.06 mg; niacin, 90 mg; pantothenic acid, 30 mg; Fe, 80 mg (as FeSO₄ ･H₂O); Zn, 80 mg (as ZnSO₄ ･ H₂O); Mn, 80 mg (as MnSO₄ ･H₂O); Co, 0.5 mg (as CoSO₄ ･H₂O); Cu, 10 mg (as CuSO₄ ･ H₂O); Se, 0.2 mg (as Na₂SeO₃); I, 0.9 mg (as Ca [IO₃] ･2H₂O).
HRW, hard red winter; SBM, soybean meal; ME, metabolizable energy; CP, crude protein; Met, methionine; Lys, lysine; Cys, cysteine; AME, apparent metabolizable energy.