Poultry encyclopedia · NEXTEKCI School · Feed raw materials
Synthetic amino acids: lysine and methionine
Proteins are made of amino acids. In a maize and soya feed, methionine and lysine are the first to run short. Synthetic amino acids make it possible to top them up precisely, balance the feed and limit excess protein. They are weighed to the gram, within a formula.
Key facts
- Most used
- Methionine, lysine, then threonine
- First shortfall (maize-soya)
- Methionine, in poultry
- Role
- Balancing the protein in the feed
- Amount
- Very small, weighed precisely
- Benefit
- Less excess protein, less ammonia
What they are
Proteins are chains made of "building blocks", the amino acids. The bird can make some amino acids itself, but not all: those it cannot make, called essential, must come from the feed.
Synthetic amino acids are these building blocks, produced industrially and sold pure, as powder or liquid. The most used in poultry farming are methionine, lysine and threonine.
Their role in the ration
What matters is not only the amount of protein, but its balance. The bird builds its muscles, feathers and eggs at the pace of the amino acid that is shortest in supply: that one limits everything else. In a maize and soya feed, this is usually methionine (also very important for feathers), then lysine (important for muscle).
By adding just the right amount of these amino acids, the nutritionist balances the feed without having to raise the oilseed meals sharply. This is called "ideal protein": each amino acid in its proper place.
What they bring
A better-balanced feed gives better growth, a better feed conversion ratio, better feathering and steadier laying. It also helps avoid excess protein: surplus protein is not only wasted for the farmer, it is excreted in the droppings as nitrogen, which wets the litter and increases ammonia in the house.
They also help make use of less well-balanced raw materials, such as cottonseed or groundnut meal, or cassava, provided the formula is made carefully.
Quality, storage and availability
Synthetic amino acids are imported and sold by suppliers of raw materials and premixes. The different forms on sale (for example of methionine or lysine) do not have the same real amino acid content: the nutritionist takes this into account in the calculations.
They are stored in their closed original packaging, in a dry place. Because they go in in very small amounts, they are weighed on accurate scales and first mixed with a small amount of feed, like premix. They are often already included in the premix or concentrate.
Common mistakes
Adding methionine or lysine "to boost growth" without a formula: without the rest of the balance it does nothing, and a large excess can even do harm. Adding more when the premix or concentrate already contains them.
Believing that a "high-protein" feed is necessarily better: a balanced feed with less protein can do better. Amino acids are decided in the formula, with the nutritionist or the feed manufacturer.