Table 1.
Ingredient composition of experimental diets (as-fed basis)1
| High E:T ratio2 | Low E:T ratio2 | |||
|---|---|---|---|---|
| SID Lys, % | 0.82 | 1.22 | 0.82 | 1.22 |
| Soybean meal | 5.0 | 5.0 | 10.0 | 10.0 |
| Corn | 79.9 | 79.4 | 75.7 | 75.2 |
| Soy protein concentrate | 8.0 | 8.0 | 8.0 | 8.0 |
| Soybean oil | 2.5 | 2.5 | 2.5 | 2.5 |
| l-Lysine | 0.297 | 0.807 | 0.135 | 0.645 |
| l-Arginine | 0.150 | 0.150 | — | — |
| dl-Methionine | 0.153 | 0.153 | 0.111 | 0.111 |
| l-Threonine | 0.242 | 0.242 | 0.172 | 0.172 |
| l-Tryptophan | 0.072 | 0.072 | 0.040 | 0.040 |
| l-Isoleucine | 0.091 | 0.091 | — | — |
| l-Valine | 0.082 | 0.082 | 0.002 | 0.002 |
| l-Histidine | 0.053 | 0.053 | — | — |
| Monocalcium phosphate | 1.38 | 1.38 | 1.32 | 1.32 |
| Limestone | 1.32 | 1.32 | 1.32 | 1.32 |
| Salt | 0.40 | 0.40 | 0.40 | 0.40 |
| Titanium dioxide | 0.10 | 0.10 | 0.10 | 0.10 |
| Vitamin/mineral premix3 | 0.20 | 0.20 | 0.20 | 0.20 |
| Calculated nutrient content 4 | ||||
| E:T | 0.36 | 0.36 | 0.33 | 0.33 |
| Dry matter, % | 87.7 | 89.1 | 88.3 | 88.2 |
| Crude protein, % | 15.3 | 15.7 | 16.6 | 17.0 |
| ME, kcal/kg | 3461 | 3466 | 3449 | 3454 |
| NE, kcal/kg | 2663 | 2667 | 2630 | 2634 |
| Ca, % | 0.77 | 0.77 | 0.77 | 0.77 |
| P, % | 0.38 | 0.38 | 0.38 | 0.38 |
| Amino acids, % SID | ||||
| Lys | 0.82 | 1.22 | 0.82 | 1.22 |
| Arg | 0.95 | 0.95 | 0.95 | 0.95 |
| His | 0.40 | 0.40 | 0.40 | 0.40 |
| Ile | 0.59 | 0.59 | 0.59 | 0.59 |
| Leu | 1.20 | 1.20 | 1.32 | 1.32 |
| Met + Cys | 0.58 | 0.58 | 0.58 | 0.58 |
| Phe + Tyr | 1.02 | 1.02 | 1.17 | 1.17 |
| Thr | 0.67 | 0.67 | 0.67 | 0.67 |
| Trp | 0.19 | 0.19 | 0.19 | 0.19 |
| Val | 0.67 | 0.67 | 0.67 | 0.67 |
E:T, essential amino acid-nitrogen:total nitrogen ratio; ME, metabolizable energy; NE, net energy; SID, standardized ileal digestible.
1The lowest and highest Lys diets were blended in appropriate proportions to achieve diets containing the other graded levels of Lys (not shown).
2E:T ratios of 0.36 (high ratio diets) and 0.33 (low ratio diets) reflect the amount of nitrogen in the diets coming from essential amino acids (E) and from all other components (T), with the higher ratio having a larger contribution of nitrogen from essential amino acids.
3Supplied per kilogram of complete feed: vitamin A, 4,000 IU; vitamin D, 0.019 mg; vitamin E, 15 IU; vitamin B12, 0.01 mg; menadione, 1.0 mg; thiamine, 0.50 mg; riboflavin, 2.0 mg; pyridoxine, 1.0 mg; niacin, 10 mg; pantothenate, 6 mg; folic acid, 0.25 mg; biotin, 0.05 mg; Cu, 7.5 mg; Fe, 50 mg; Mg, 20 mg; I, 0.50 mg; Zn, 50 mg, and Se, 0.15 mg.
3Nutrient content of diets based on estimated nutrient contents of ingredients according to NRC (2012).