Table 1.
Composition of experimental diets fed to determine the standardized ileal digestible (SID) lysine requirement and the optimum SID lysine (Lys) to threonine (Thr) ratio for finishing barrows (%, as-fed basis)
| Exp.1
|
Basal diet for Exp. 22 | ||||||
|---|---|---|---|---|---|---|---|
| Normal-CP 1 | SID lysine level in low-CP1 diets
|
||||||
| 0.51% | 0.61% | 0.71% | 0.81% | 0.91% | |||
| Corn (7.8% CP) | 75.40 | 78.58 | 78.58 | 78.58 | 78.58 | 78.58 | 79.63 |
| Wheat bran (16.8% CP) | 1.50 | 12.00 | 12.00 | 12.00 | 12.00 | 12.00 | 13.50 |
| Soybean meal (43.5% CP) | 20.50 | 5.00 | 5.00 | 5.00 | 5.00 | 5.00 | 3.50 |
| Corn starch | 0.00 | 0.33 | 0.27 | 0.18 | 0.09 | 0.00 | 0.00 |
| Limestone | 0.90 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Dicalcium phosphate | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 | 0.70 |
| Salt | 0.40 | 0.40 | 0.40 | 0.40 | 0.40 | 0.40 | 0.40 |
| L-lysine·HCl | 0.10 | 0.25 | 0.37 | 0.50 | 0.63 | 0.75 | 0.43 |
| DL-methionine | 0.00 | 0.00 | 0.06 | 0.13 | 0.19 | 0.25 | 0.10 |
| L-threonine | 0.00 | 0.05 | 0.12 | 0.19 | 0.26 | 0.33 | 0.06 |
| L-tryptophan | 0.00 | 0.01 | 0.02 | 0.04 | 0.06 | 0.08 | 0.04 |
| L-isoleucine | 0.00 | 0.00 | 0.03 | 0.09 | 0.14 | 0.20 | 0.08 |
| L-valine | 0.00 | 0.00 | 0.01 | 0.07 | 0.14 | 0.21 | 0.06 |
| L-alanine | 0.00 | 1.18 | 0.94 | 0.62 | 0.31 | 0.00 | 0.00 |
| Vitamin and mineral premix3 | 0.50 | 0.50 | 0.50 | 0.50 | 0.50 | 0.50 | 0.50 |
Normal-CP and low-CP represent diets that were formulated to contain 15.3% CP with 0.71% SID lysine and 12% CP with SID lysine of 0.51, 0.61, 0.71, 0.81 and 0.91%.
Diets in Exp. 2 were formulated to contain 0.61% SID lysine and were created by replacing part of the corn of the basal diet with 0, 0.04, 0.09, 0.10 and 0.13% L-threonine.
Supplied per kilogram of diet (as-fed basis): vitamin A, 7,200 IU; vitamin D3, 1,400 IU; vitamin E, 20 IU; vitamin K3, 0.5 mg; thiamine, 1.6 mg; pyridoxine, 2 mg; vitamin B12, 24.0 μg; riboflavin, 4.0 mg; pantothenic acid, 12.0 mg; niacin, 24.0 mg; folic acid, 0.8 mg; choline chloride, 400 mg; Fe, 120 mg (as ferrous sulfate); Cu, 75 mg (as copper sulfate); Zn, 100 mg (as zinc sulfate); Mn, 40 mg (as manganese sulfate); I, 0.3 mg (as calcium iodate); Se, 0.3 mg (as sodium selenite); Beijing Resource Feed Company, Beijing, China.