What are Feed-Use Amino Acids?

Proteins, indispensable compounds for all animals, consist of 20 different amino acids. Some essential amino acids have to be taken from feedstuffs because animals’ bodies cannot synthesize sufficient amounts. There are around ten different essential amino acids, depending on the species and growth stage of animals. Adding amino acids to feed reduces feed costs, improves feed efficiency, and enhances animal growth. Lysine, Methionine, Threonine, Tryptophan and Valine are commonly used in feeds, since these essential amino acids tend to be deficient in natural feedstuffs. The Group produces feed-grade Lysine, Threonine, Tryptophan and Valine.

Lysine Content in Natural Feed Ingredients

With the exception of comparatively lysine-rich soybean meal (2.7-2.9 percent), natural feed ingredients such as corn (0.22 percent) and wheat (0.3 percent) contain little lysine. Adding Lysine to feed deficient in lysine improves the balance of amino acids, which improves feed efficiency and reduces nitrogen excretion.

Barrel Theory

The barrels at the right are a model for protein values. Each individual stave represents the degree of sufficiency for a particular amino acid. Barrel 1 shows the amino acid pattern of wheat. In Barrel 2, adding supplemental Lysine to the same level as that of threonine (the second limiting amino acid) raises the total protein value to the level where lysine and threonine become co-limiting. Barrel 3 shows Lysine and Threonine added to the level of the third limiting amino acid (tryptophan), demonstrating how amino acid supplementation improves the nutritional value. By adding Lysine and Threonine, the protein value of wheat can be improved by 25-50 percent.

From Feed with Added Amino Acids to Meat Products

To formulate feed, feed-use amino acids are added with vitamins and other substances to soybean meal, corn, wheat and other natural feed ingredients.

Essential Amino Acids for Livestock

Correlation between the Grain Market and Prices of Feed-Use Lysine and Threonine

A feed that is mainly composed of corn and soybean meal helps illustrate the correlation between the grain market and the prices of Lysine and Threonine. Soybean meal, used as a protein source, is relatively rich in lysine, while corn, a primary energy source, contains much less.

For example, if the price of soybean meal is high and the price of corn is low, feed manufacturers prefer to use more corn to save on feed costs. In this case, however, feed must be supplemented with Lysine so that animals’ requirements for this amino acid are met. The theoretical maximum price for Lysine can be determined through comparison with the cost of lysine supplied with soybean meal. This maximum price is called the shadow price (or the opportunity price).

Theoretically, the Lysine inclusion rate in the feed would not differ until the price reaches the shadow price. However, when the price of Lysine exceeds the shadow price, its inclusion rate will be reduced in order not to increase feed cost. The shadow price varies according to the type of feed and the species and growth stage of the animal. The larger the difference (the “spread”) between the price of soybean meal and corn, the higher the shadow price becomes. In Europe, where wheat is used as a primary energy source instead of corn, which is commonly used in the U.S.A., the spread between the prices of soybean meal and wheat takes the place of the soybean meal/corn spread in determining the shadow price of Lysine.

Also, since threonine is generally the second limiting amino acid after lysine, the shadow price of Threonine is affected not only by the spread but also by the price of Lysine. The shadow price of Threonine rises when the price of Lysine is low, and vice versa.

■Factors Creating Demand for Feed-Use Lysine

■Correlation between the Spread (Difference between Soybean Meal and Corn Prices) and Lysine/Threonine Prices

■Correlation between Threonine and Lysine

When the price of Threonine is relatively low compared to its shadow  price

When the price of Lysine is relatively low compared to its shadow price

Contributions of Feed-Use Amino Acids: Natural Protein Conservation, Effective Use of Farmland

Feed-use amino acids contribute to the conservation of natural protein sources and effective use of farmland. Generally, soybean meal in feed can be partially replaced with corn and Lysine using the following formula:

50kg soybean meal = 48.5kg corn + 1.5kg Lysine


This means that using one metric ton of Lysine can save about 33 metric tons of soybean meal. Worldwide use of feed-use Lysine has been increasing every year along with expansion of feed production and progress of Lysine use. For example, if 1.2 million metric tons of Lysine is used, this means about 40 million metric tons of soybean meal can be replaced by 38.8 million metric tons of corn and Lysine. Looking at the potential reduction of soybean meal production in terms of the total area of farmland needed, since the per hectare yield for corn is far greater than for soybeans, lowering the amount of soybean meal used in feed would result in a potential reduction of approximately 14 million hectares in the amount of land required. In other words, this hectarage of land would have to be cultivated to secure the quantity of soybeans required to produce feeds without Lysine.

Contributions of Feed-Use Amino Acids: Solving Environmental Problems

Feed formulations are normally calculated by computer, using linear programming to determine the lowest cost while meeting nutrient requirements with available feed ingredients. Adding supplemental limiting amino acids such as Lysine based on the barrel theory improves the amino acid balance and efficiency of feeds. This reduces the amount of plant protein sources required.


Without the addition of limiting amino acids, it is difficult to achieve an ideal dietary amino acid balance using only plant protein, which leads to an excess of protein in the feed and the oversupply of unnecessary amino acids. These excess amino acids are not utilized by the animals, and are excreted as nitrogen compounds. The ammonia generated by the excreted nitrogen compounds causes odors. In addition, excess excretion of nitrogen leads to soil contamination and pollution of surface and groundwater. Environmental pollution from this nitrogen is a big concern in livestock production.


On the other hand, the addition of Lysine is effective in reducing the LC (life-cycle)-CO2 (total volume of CO2 produced from manufacture of raw materials to production) of formulated feeds. (As an estimate, each kilogram of added Lysine reduces LC-CO2 produced by 1 ton of feed by 2.4kg.*)


Using limiting amino acids in feed in this way reduces excess intake of other amino acids and proteins. As a result, they contribute to resolving the environmental issue of reducing excretion of nitrogen and LC-CO2 into the environment.


* Estimated LC-CO2 is calculated using average figures from the Group’s current Lysine production, with a soybean meal/corn diet, and it is not necessarily applicable to Lysine in general.