Amino acids nutrition


Twenty amino acids are the building blocks of proteins (Table 1). Some of them can not be synthesised, or not in sufficient quantities, by animals; they must therefore be supplied through the feed and are referred to as indispensable amino acids. The indispensable amino acids could differ depending on the species (Table 2). To maintain good health and growth performance, feeds must provide the indispensable amino acids in sufficient quantities to cover the requirement of animals.

Amino acid 3-letter Amino acid 3-letter
AlanineAlaLeucineLeu
ArginineArgLysineLys
AsparagineAsnMethionineMet
Aspartic acidAspPhenylalaninePhe
CysteineCysProlinePro
Glutamic acidGluSerineSer
GlutamineGlnThreonineThr
GlycineGlyTryptophanTrp
HistidineHisTyrosineTyr
IsoleucineIleValineVal

Table 1. The 20 amino acids encoded directly by the genetic code and their 3-letter abbreviations

Essential amino acids (EAA)
Amino acids involved in the biological functions that are necessary for life supplied through the diet or synthesised de novo by animals.
PigsBroiler
• Indispensable amino acids
EAA that can not be synthesised de novo or at a sufficient rate to maintain the associated biological functionsLysLys
ThrThr
MetMet
TrpTrp
ValVal
IleIle
LeuLeu
HisHis
PhePhe
Arg
• Dispensable amino acids
Conditionally or semi-dispensable amino acids
EAA that can be synthesised de novo but that could become indispensable in specific situations when the synthesis become not sufficient to cover the requirementCysCys
TyrTyr
Arg
Strictly dispensable amino acids
EAA that can be synthesised de novo by animals in a sufficient rate in any casesGlu, Gln, Gly, Ser, Pro, Asp, Asn, Ala

Table 2. Classification of the 20 amino acids encoded directly by the genetic code, for pigs and broiler

 

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