This study was conducted to determine the DE, ME, and apparent (AID) and standardized ileal digestibility (SID) of AA in different wheat cultivars fed to growing pigs. In Exp. 1, twelve crossbred growing barrows were allotted to a replicated 6 × 6 Latin square design to determine the DE and ME contents of 12 different wheat cultivars. In Exp. 2, twelve growing barrows with a simple T-cannula were used to determine the AID and SID of AA in 10 different wheat cultivars. Pigs were randomly allotted to a replicated 6 × 6 Latin square design and fed one nitrogen-free diet and 10 different cultivars of wheat diets. Among different wheat cultivars, the concentrations of GE, CP, NDF, ADF, and starch ranged from 4,385 to 4,458 kcal/kg, 12.95% to 18.14%, 9.16% to 13.89%, 1.93% to 2.92% and 60.81% to 70.77%, respectively (DM basis). There were significant differences (P < 0.05) in the DE, ME values, and the ATTD of GE in 12 different cultivars of wheat in Exp. 1. The DE and ME contents and the ATTD of GE ranged (P < 0.05) from 3,922 to 4,067 kcal/kg DM, 3,759 to 3,941 kcal/kg DM and 88.14% to 90.31%, respectively. The best prediction equations of DE and ME for different cultivars of wheat cultivars were DE = −2,738 -(40.8 × % ADF) + (1.7 × GE) -(51.5 × % Xylans) -(95.7 × % Ash) + (22.3 × % EE), R 2 = 0.98, and ME = −2,990 + (1.7 × GE) -(50.2 × % Xylans) -( 87.6 × % Ash), R 2 = 0.88, respectively. There were also differences (P < 0.05) in the AID and SID of CP and indispensable AA, expect for His, in 10 wheat cultivars in Exp. 2. The AID and SID of CP, Lys, and Met ranged (P < 0.05) from 82.02% to 89.46%, 74.13% to 84.73%, 87.35% to 92.49% and 87.56% to 94.04%, 80.56% to 89.89%, 89.56% to 94.45%, respectively. In conclusion, the chemical composition, energy contents, and most AA digestibility in different cultivars of wheat varied widely.
