What Are Amino Acids? Why Do They Matter in Feeds?

Animals need different amino acids for growth, the formation and renewal of tissues and various metabolic activities.

So when assessing the protein value of a feed, looking only at the crude protein content is not enough. Which amino acids the protein provides, and in what quantities, also matters.

Some of the amino acids animals need cannot be produced in the body in sufficient quantities, or not at a level that meets the animal’s needs. These must be supplied through feed.

These amino acids are of particular importance in feeding and are given separate attention when preparing a ration.

The amino acids that matter, and the levels needed, may vary with the animal species.

Lysine and methionine are among the essential amino acids most often assessed, especially in the formulation of poultry feeds.

Lysine is an important amino acid for growth and particularly for the formation of body proteins.

Methionine plays a part in various metabolic processes as well as in protein synthesis. As a sulphur-containing amino acid, it also has properties that differ from those of other amino acids.

In poultry feeds, therefore, it is important that not only the crude protein content, but also amino acids such as lysine and methionine, are sufficient and balanced.

When preparing a compound feed, the aim is not just to combine raw materials with a high protein content.

The amino acids the animal needs must be provided at suitable levels according to its species, age, live weight and production period.

For this reason, different protein sources can be used together and, where necessary, the levels of specific amino acids can be adjusted separately in the formulation.

The right approach is to assess the amount of protein and its amino acid structure together.

A feed containing a particular amino acid does not mean that all of that amino acid can be used by the animal.

How far amino acids are digested and can be used by the animal also matters.

In advanced feed formulations, therefore, not only total amino acid amounts but also the availability and digestibility of amino acids can be taken into account.

Amino acid needs are not the same in all animals.

The protein and amino acid needs of a broiler, a laying hen, a dairy cow or a fattening animal differ according to species, age, live weight and production period.

For example, in fast-growing broilers the amino acid balance matters for growth performance, while in laying hens the nutrient balance required by egg production is taken into account.

A feed’s suitability in terms of amino acids should therefore always be assessed with regard to the animal it was prepared for.

In organic feeds, too, the animal’s protein and amino acid needs must be met.

However, the compliance of the raw materials used with organic production and sourcing conditions is assessed separately.

In organic feed formulation, therefore, both the animal’s nutrient needs and the compliance of the raw materials used with the relevant organic requirements should be considered together.

Amino acids are the building blocks of proteins and are of fundamental importance in animal feeding.

The crude protein content is an important indicator in assessing a feed, but on its own it is not enough. The amount and balance of essential amino acids such as lysine and methionine in particular should also be taken into account.

In correct feed formulation, the goal is to provide a protein and amino acid balance suited to the animal species and production period, rather than to reach a high protein content.