Energy systems used in poultry: Interview with Dr. Craig N Coon

Formulation Nutrition Raw Materials Research

Energy systems used in poultry nutrition are still a matter of discussion amongst experts.There are several factors that affect production efficiency in poultry production amongst which an adequate and balanced supply of energy and macro- and micro-nutrients holds great importance. Energy in itself is not a nutrient, but a property of energy-yielding nutrients such as carbohydrates, lipids, and protein. Dietary energy represents the most important component in poultry feed formulations as well as the most costly. When diets are formulated, energy is is the first component to be taken into account while also being a determinant factor in feed consumption. Which in turn is the main driving force behind bird growth.

For such reasons precise evaluations of ingredients and their energy content are of utmost importance when it comes to formulating efficient and low cost diets in poultry production.The metabolizable energy (ME) system became a commonly accepted and extensively used tool in poultry nutrition. As it allows to establish available energy content in different feed ingredients, bird energy requirements which are key when formulating complete poultry feeds. However, this system far from being perfect, considering the fact that it holds various limitations.

Dr. Edgar Oviedo collaborator and co corresponding author for nutriNews International had the opportunity to discuss this interesting subject on a short interview with Dr. Craig N Coon. Dr. Coon is a Poultry Nutritionist who serves as Director of the Experiment Station at the University of Arkansas . This interview took place during the 7^th EAAP International Symposium on Energy and Protein Metabolism and Nutrition (ISEP 2022) held in Granada (Spain) from September 12-15, 2022.

Dr. Edgar Oviedo: We are pleased to welcome Dr. Craig N Coon. He is a professor at Arkansas University dedicated to breeder, layers, and broiler nutrition. He has developed an excellent method on net energy

What are the differences between the Arkansas energy system and other net energy systems?

Dr. Craig N Coon: What we see is that the broilers for which we are making this system are growing very fast and putting on a great amount of protein. That means you have to feed a lot of protein and a great amount of digestible amino acids in order for these birds to perform well. If you look at the energy system that we have they are not really made up for that. If you look at the ME systems and the way most people use ME. They use nitrogen correction and they nullify all responses regarding the contributions of amino acids, as they only look at them as a catabolic compound to be metabolized. Which is not the whole purpose of amino acids. Then if you look at net energy, it is just as bad or even worse. In the net energy systems, what they usually do is that they subtract Heat increments from AME. The main nutrient that affects heat increment is protein and amino acids. So, what you see is that this truly downgrades the value of amino acids and protein for net energy systems. Therefore, both of these systems are going in the wrong direction completely.

Our birds in the future are going to be more of a protein type of bird. We are trying to produce protein for the world, which mean we are going to have to increase the protein deposition of these birds. Meaning we are going to have to feed more protein and amino acids to do that. That is why in my opinion al the other energy systems are going to be ineffective. And they don’t have anything to do with body composition. What we are now using is nothing more than productive energy. Arkansas NE is productive energy. It is completely performance driven. All the values that we get are based on what the bird does, so we are looking at the gain, the maintenance in the way we are really supposed to look at net energy. Net energy is gain and maintenance, and we are looking at both parts, we are not just simply takin AME and subtracting heat increment to call it NE, as that gives you nothing. We are actually giving you the real performance created by this nutrient.

Dr. Craig N Coon: I think the whole thing will be developed for something as simple as the NIR. We have to develop very good digestible nutrient variables of all of our ingredients and then with a good NIR system we can take any ingredient and find: the digestible starch, digestible fat, the digestible amino acids. We can actually look at fiber in many different ways. There are some positive aspects of fiber. If you at the soluble fibers they are actually very good. Then if you go into the insoluble fibers some those are really more of a diluent and they can lead to some negative aspects. We have to come up with a very good predictive coefficient system for all o the nutrients that our birds are using. With that anyone can take an NR value of their ingredients and know what all these nutrients are and put it together and actually have an Aransas NE value for that ingredient.

Edgar Oviedo: The other aspect would be, what are the predictions of the requirements for the birds? In what species can these productive values be used already. Are we at the point where we can use them for broilers, breeders, and layers? Or at what stage is this system?