Comparison between the Sequences of Limiting Amino Acids as Determined by the True Amino Acid Digestibility and the Chick Growth Assay Methods

Abstract

The available amino acid score method (AAS) of Sarwar (1984) was used to rank the available amino acids in two fish meals relative to the amino acid requirements of growing chicks. This ranking was compared with the sequences previously determined by Schelling's (1975) complete protein evaluation method (CPE) (Haque et al., 1989). The AAS of arginine, methionine, tryptophan, isoleucine, histidine and phenylalanine showed the lowest values, leucine, valine and threonine showed intermediate values and lysine and glycine the highest values. These results agreed well with the CPE findings. Data obtained on true amino acid digestibility (TDA), protein efficiency ratio (PER), net protein ratio (NPR), available lysine for chicken, in vitro protein digestibility, 1-fluoro-2,4-dinitrobenzene-reactive-lysine (FDNB-lysine) were used to compare the protein quality of the two fish meals.

Key Words:

• available amino acid score
• digestibility
• availability
• chicken
• protein quality
• fish meal