Amino acids in animal nutrition: role and importance
Understanding amino acids in animal nutrition
Amino acids are the building blocks of proteins. Some are essential because the animal cannot synthesize them.
Essential amino acids
- Lysine: first limiting amino acid in swine and often in poultry. Essential for muscle growth.
- Methionine: first limiting in poultry. Involved in feather and eggshell synthesis.
- Threonine: third limiting. Important for immune function.
- Tryptophan: serotonin precursor. Influences appetite and behavior.
Ideal protein concept
The ideal protein concept expresses amino acid needs as ratios relative to lysine (= 100). For broiler grower: methionine+cystine = 72% of lysine, threonine = 65%.
Digestibility: the value that matters
Standardized ileal digestibility (SID) is the reference measure used in modern formulation. Feed Access integrates SID values in its optimization calculations.