Ideal Protein for Pigs: Lysine Ratios for Threonine, Methionine and Tryptophan

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On October 17, 2026

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Quick answer: The ideal protein concept expresses each essential amino acid as a percentage of lysine, the reference amino acid for pigs. Typical growing-pig ratios on a digestible basis are roughly threonine 65%, methionine plus cystine 60% and tryptophan 18% of lysine. Formulating to these ratios with synthetic amino acids lowers crude protein, cost and nitrogen waste.

Updated October 2026 · NDRG Kokal Enterprise, Sarawak, Malaysia

Key facts

Reference amino acid	Lysine (100%)
Threonine	About 65% of lysine
Methionine + cystine	About 60% of lysine
Tryptophan	About 18% of lysine
Basis	Standardised ileal digestible (SID)
Benefit	Lower protein, cost and nitrogen

What is ideal protein?

Pigs need amino acids in a specific balance. Instead of listing absolute amounts for every stage, nutritionists set lysine first and express other amino acids as ratios. When lysine changes with age or genetics, the others follow automatically.

Typical ratios (growing pigs, SID basis)

Amino acid	Ratio to lysine
Lysine	100%
Threonine	About 65%
Methionine + cystine	About 60%
Tryptophan	About 18%
Valine	About 65–70%

Ratios vary between guidelines and production stages; use your nutritionist’s or genetics supplier’s values.

Putting it into practice

Set SID lysine for the pig’s stage.
Use L-lysine HCl and DL-methionine to meet ratios with less soybean meal.
Check threonine and tryptophan once crude protein is lowered.

Learn more in our lysine in pig feed guide.

Frequently asked questions

What is the ideal protein concept?

A way of formulating diets where each essential amino acid is set as a ratio to lysine.

Why is lysine the reference amino acid for pigs?

It is usually first limiting and is used mainly for protein deposition, making it a stable reference.

What is the threonine to lysine ratio for pigs?

Typically about 65% on a digestible basis for growing pigs, though guidelines vary.

Buy in bulk: request a wholesale quote from NDRG Kokal Enterprise, Siburan, Sarawak. Call or WhatsApp +60 13-739 1922 or email info@ndrgkokalenterprise.com.

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