290 W.C. Sauer et al.
Fig. 13.4.The quadratic with plateau relationships between the apparent ileal crude protein and amino
acid digestibility values (Y: %, means ± SE) and the dietary crude protein content (X: g kg^1 , on dry matter
basis). CP, crude protein; THR, threonine; TYR, tyrosine; and MET, methionine (Fan et al., 1994).
Table 13.3.The range of crude protein and amino acid contents (g kg^1 , on dry matter basis) in the assay
diets for the determination of apparent ileal crude protein and amino acid digestibility values in cereal grains.
Barleyb–f,h–k Wheata–f,i–k Maizeb,e–g,j Threshold levell
Cereal grains (n=12) (n=15) (n=5) (n=1)
Crude protein 105–149 121–193 82–125 171
Amino acids
Indispensable
Arginine 4.8–7.4 5.4–7.1 3.6–4.5 11.5
Histidine 2.3–3.3 2.5–3.6 2.3–2.5 4.3
Isoleucine 3.7–5.2 4.6–5.5 3.3–3.5 8.3
Leucine 6.8–9.8 8.3–10.2 10.9–13.1 13.3
Lysine 3.9–4.6 3.1–4.6 2.3–3.4 9.4
Phenylalanine 4.5–8.2 5.5–6.8 3.8–5.2 8.2
Threonine 3.4–4.7 3.1–4.5 2.7–3.6 6.3
Valine 5.0–7.1 5.6–6.5 4.5–4.6 8.4
Dispensable
Alanine 4.0–5.4 3.8–5.2 5.2–7.6 6.9
Aspartic acid 6.1–8.1 5.4–8.0 5.1–7.2 17.1
Glutamic acid 24.4–40.6 31.1–51.7 13.9–20.9 23.1
Glycine 3.1–5.8 4.1–4.8 2.6–4.0 6.7
Serine 3.8–6.0 5.0–6.3 3.8–5.1 8.7
Tyrosine 2.1–4.4 3.1–3.3 3.1–4.0 6.2
aIvan and Farrell (1976); bSauer et al. (1977a,b); cSauer et al. (1981); dJust et al. (1985); eLin et al. (1987);
fGreen et al. (1987); gVan Leeuwen et al. (1987); hImbeah et al. (1988); iDe Lange et al. (1990); jFuruya and
Kaji (1991); kFan et al. (1993); lFan et al. (1994).