Amino Acids

If you’ve ever asked the Fertrell nutrition staff for a poultry or swine ration, there’s a good chance we mentioned “amino acids” to you. Although these compounds are a regular part of our nutritional landscape, not everyone may fully understand what they are, why they’re important, and how to ensure your animals get enough of them.

If you ask a nutritionist what an amino acid is, they’ll likely say, “they’re the building blocks of proteins.” This is spot on, but to be more specific, a protein is a chain of linked amino acids.

There are hundreds of amino acids in nature, but only 22 make up the proteins found in living organisms. Of these, some are considered “essential,” meaning they must be provided in the animal’s diet because the animal can’t synthesize them from other amino acids. For poultry, these essential amino acids are arginine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Most of these are supplied in adequate levels by common feedstuffs, but for some, we need to pay close attention to the levels in the rations. For poultry and swine, the critical ones to watch are lysine, methionine, and threonine. We only look beyond these if very alternative feedstuffs are used.

If these essential amino acids aren’t provided in adequate amounts, protein synthesis will be limited by the availability of the least abundant essential amino acid.

This concept is well illustrated by the barrel above, where lysine is the limiting amino acid. The more water the barrel can hold, the more protein is synthesized.

If your ration is a “typical” one, containing corn and soy, you won’t need to worry as much about essential amino acid levels. This is because soy contains all essential amino acids in fairly good amounts.

However, if your ration is soy-free, there’s a higher likelihood of an amino acid deficiency. This is why we need to put more effort into balancing a soy-free ration with multiple protein sources, each with different levels of amino acids. For example, peas are high in lysine but low in methionine, while sesame meal is high in methionine but low in lysine, so the two pair well together.

In both soy-based and soy-free rations, you can also add synthetic amino acids. These are isolated amino acids that are 98-99% pure. Certified Organic production is very restrictive in its use of synthetic amino acids, but if you’re not certified, you might consider using them. Modern strains of poultry, especially layer and broiler hybrids, benefit greatly from amino acid levels that are hard to achieve with natural feedstuffs alone. If we try to meet these levels using only natural feedstuffs, the overall protein content will become very high. This can significantly increase the cost of the ration and lead to excessive nitrogen loss from the extra protein. A few pounds of synthetic amino acids can save several percentage points of total crude protein in the ration.

I hope this article has helped you better understand our goals when it comes to amino acid levels. If you ever have any questions about the amino acids in your ration, please feel free to contact the office and ask for the nutrition team!