Of the 22 amino acids [AA] that are used by the animal’s body for protein
synthesis and tissue renewal, 10 are considered essential [indispensable: essential
amino acids; EAA]. The essentiality of an AA is defined by whether or not the animal
is able to synthesize the key AA of interest at all, or at a rate that is sufficient
to meet its needs [requirements] for normal metabolic processes, growth and production.
On the flipside, non-essential amino acids [NEAA] are those AAs that the animal
can synthesize at a rate that supports normal metabolic processes, growth and production.
These amino acids can be synthesized from other non-EAAs and/or EAAs via the process
of transamination. Because the animal is unable to adequately synthesize EAAs and
EAAs can be irreversibly transformed into non-EAAs, EAAs must be supplied by some
dietary source either from intact protein or in free-form [commercially-available
In order to maximize the genetic potential of a given livestock species [growth,
feed conversion, muscle yield, reproductive performance, etc.], AAs must be provided
in the correct quantities and balance. This is often referred to as the “ideal protein
concept” or the “Barrel-Stave concept”. The Ideal Protein and Barrel-Stave concepts
simply state that there is an order of limitation / relationship between the levels
of EAAs. Nutritionally, if the amount of growth rate is dictated by the amount of
the first limiting amino acid [ex. Lysine], then all EAAs present in the diet [assuming
each is in excess of the animal’s requirement] can only be utilized to the extent
that the first limiting AA meets the requirement of the animal. Think of this as
a bottleneck or regulator. Once the need for the first EAA is met, then the second,
third, etc. must be met in order for the animal to optimize its growth response.
Once the requirement for EAAs and NEAAs is met, all other AAs that are supplied
in excess of the limiting AAs will be broken down [catabolized] into a carbon chain
that is used for energy and a number of nitrogenous compounds that are then excreted
in to the environment [i.e. free ammonia, urea (in mammals) or uric acid (in birds)].
Since excess AAs are not stored by the body, the ultimate goal is to meet the animal’s
AA requirements for production, while reducing the amount of nitrogen that is excreted
in to the environment.
As mentioned above, AAs can be added to a diet as intact protein or in free form
[i.e. commercially-available AAs]. Once the AA requirements for a particular livestock
at a given stage of production are established, commercially-available AAs can be
supplemented into diets as a way of meeting the specific requirement of those AAs.
This approach not only minimizes excess dietary protein and N excretion in to the
environment, which would happen if intact protein sources were used to meet a specific
AA requirement, but also the cost of the diet as the level of expensive, protein-rich
ingredients is reduced in the dietary formulation.
Ajinomoto Animal Nutrition North America, Inc’s parent company, Ajinomoto, has over 100 years experience
in the research, development and application of crystalline AAs in monogastric nutrition.
Using fermentation technology, L-Lysine mono-hydrochloride, Liquid L-Lysine, L-Threonine,
L-Tryptophan, L-Valine and L-Isoleucine are economically and environmentally sound
options for today’s animal agriculture and companion animal nutrition programs.