Release the potential of your feed

In European vegetable feed formulas, valine is usually the fifth limiting amino acid after tryptophan for pigs and the fourth one after threonine for broiler. As lysine, threonine and tryptophan, valine is an indispensable amino acid for body protein deposition and growth. Thus, deficiency in valine affects the utilization of previous dietary limiting amino acids and consequently animal growth. 

Valine is included in the branched-chain amino acids (BCAA) group, together with isoleucine and leucine. Due to their common catabolic pathway, some interactions exist between them. That is why it is very important to well know their requirements and to ensure that they are neither under- nor oversupplied in animal feeds.

L-Valine supplementation aims at meeting the nutritional requirement of the animals. In piglets, a minimum of 70% SID Val:Lys must be supplied in the feed to optimize growth performance (Figure 1).

Digestible lysine level in feed

Figure 1. Estimation of the standardized ileal digestible valine to lysine (SID Val:Lys) minimum requirement for piglets between 7 and 30kg live weight; average daily gain (ADG, % of the best performance) and feed conversion ratio (FCR, % of the best performance) are optimised

This recent compilation by Ajinomoto Animal Nutrition Europe has corroborated previous literature findings and confirmed that a minimum requirement ratio at 70% SID Val:Lys ratio must be considered as a recommendation for optimum piglet growth. In practical situations, L-Valine supplementation to balance piglet diets leads to a significant improvement in growth performance.

In broilers, a recent compilation of 10 experiments estimated the TD Val:Lys ratio requirement at 80% to maximize growth and feed efficiency (for details, see Bulletin N°36 Update on the next limiting amino acid in broiler feeds - Reducing dietary crude protein level).

With L-Valine available today, it becomes easier to formulate pigs and poultry diets without minimum crude protein (CP) constraint. The use of L-Valine in feeds means that the amino acid requirements of animals can be satisfied without causing an imbalance in amino acids.

The tables below give a summary of Ajinomoto Animal Nutrition Europe proposals concerning valine requirements per species and per growth stage when justified. These requirements, in accordance with the concept of the ideal protein, are expressed relative to lysine on a SID basis for swine and on a TD basis for poultry.

Growing pigs
Piglets Grower - Finisher
SID Valine:Lysine (%) 70 > 65
Lactating sows
SID Valine:Lysine (%) > 85
Broiler chicken Laying hens
TD Valine:Lysine (%) 80 90

L-Valine to further reduce dietary crude protein:

Until the release of feed grade L-Valine in 2009, valine was the next limiting amino acid in piglet feeds and, constraints on dietary CP led to formulations with either an imbalanced amino acid profile (valine deficiency) or with low lysine dietary concentrations to keep a balanced amino acid profile. In both cases, growth performance was lower than piglets’ potential. Current feeds using L-Valine increase their value by meeting valine requirements and thereby allowing complete utilisation of the other nutrients. Consequently lysine levels can be increased to allow piglets to express their full potential for growth; and dietary CP content can be further reduced to improve health conditions, avoid digestive disorders, improve feed efficiency and reduce the nitrogen excretion into the environment.

The reduction of CP in feeds has indeed been limited by a lack of information on the exact level of valine that is required for optimum growth and, to a large extent, by the non-availability of feed grade L-Valine. Ajinomoto Animal Nutrition Europe's new L-Valine gives the feed industry the opportunity to implement further decreases in dietary CP content (Figure 2), which can be driven by nutritional, economic and environmental goals.

Digestible lysine level in feed

Figure 2. Dietary crude protein (CP) level in a standard diet for starter piglets (soybean meal is gradually replaced by wheat). Ranking of the limiting amino acids (from left to right) and CP level achievable without supplementation with the corresponding amino acid.

On the basis of a piglet feed containing 70% SID Val:Lys ratio, the use of L-Valine breaks through the old feed optimisation barrier allowing a further decrease in the dietary CP content of about 2 percentage points of protein.

As for L-Lysine, L-Threonine and L-Tryptophan, L-Valine supplementation in monogastric feeds represents a simple, effective and accurate way of adjusting valine content to animal requirements to optimize the technico-economic results of the production. The availability of L-Valine offers a new opportunity to formulate more efficient diets through the optimisation of the ideal amino acids profile. L-Valine supplementation indeed contributes to a better utilization of the other amino acids and of the feed in general. In association with L-Lysine, L-Threonine and L-Tryptophan, the use of L-Valine makes it possible to further reduce the dietary CP content and, as a consequence, to reduce nitrogen excretion from animal husbandry in the environment. In piglets and broilers, these feeds with increasingly lower protein content are frequently used to limit the occurrence of digestive problems. As L-Lysine, L-Threonine and L-Tryptophan, L-Valine is 100% digestible, so its utilization by the animal is far greater than that of protein-bound valine from vegetable proteins.

The leaflet here below summarizes the role of valine and the benefits of supplementing feeds with L-Valine.

The article below presents data on valine requirements in piglets and broiler.


For further information, please read our technical bulletins: numerous experimental results are reported.