Ideal protein—and its suitability to characterize protein quality in pig feeds. A review

Abstract

A new method for defining the protein quality in feedstuffs and pig diets, based on the amino acid composition of true ileal digestible protein relative to the pattern of ideal protein, is introduced.

The scientific background for the ideal protein concept is investigated. The amino acid patterns of ideal protein given in the literature correspond to either the total amino acid composition in traditional or semi‐purified diets or the apparent digestible amino acids in traditional diets. The obtained patterns are influenced by the method of determination. The ideal amino acid pattern relative to lysine and N, respectively, is discussed. In the present paper the ideal amino acid pattern is calculated from true ileal digestible amino acids relative to true ileal digestible N and the following standard composition (g per 160 g N) is proposed: lysine 70, methionine 18, methionine + cystine 36, threonine 45, tryptophan 12, isoleucine 40, leucine 80, histidine 25, phenylalanine 40, phenylalanine + tyrosine 80, valine 52.

Key words:

• amino acids
• essential
• maintenance
• non‐essential
• protein accretion
• requirements