Effects of dietary amino acids in ameliorating intestinal function during enteric challenges in broiler chickens
Published:February 4, 2020
Summary
ABSTRACT Enteric infections such as coccidiosis and necrotic enteritis in broilers may have a large influence on the endogenous amino acids (eAA) losses within the gastrointestinal tract (GIT). Although not much is known on this topic, more information is available on the effects of these diseases on the apparent ileal digestibility (AID) of amino acids. There are many factors that must be con...
Dr. Cristiano, we congratulate the team involved in preparing the article, considering the information contained therein. I would like to take the opportunity of the material presented, to make some considerations regarding the implications of the practice of reducing crude protein (CP) in diets for pigs and poultry. First; - it became evident that the demand for essential amino acids, such as threonine, tryptophan and sulfur dioxide is increased in conditions of immunological challenge. Therefore, the relationships between these amino acids and lysine in the ideal protein of these animals are increased. With these facts, it became evident that the ideal protein has a dynamic character, revealing the need for adjustments in the relationships of these amino acids with lysine according to the animal's health status. Second, - the evidence that the non-essential amino acid, glutamine, can become limiting depending on the degree of the animal's immune challenge, is also a restriction to the practice of reducing crude protein in the feed. I made these considerations not in the sense that it is not feasible to reduce CP in poultry and swine diets, but in the sense that there is a need for the use of common sense when we advocate this practice. very well addressed in this article., other non-essential amino acids such as glutamate, aspartate and glycine, can also become limiting in pig and poultry diets depending on the animals' immune stress.
Under immunological challenge, the animal uses the limiting AA for the synthesis of acute phase protein and other proteins that involve in immune system development at the expense of muscle accretion leading to growth depression. Therefore, in immune compromised animals the demand for these AA increases necessitating extra supplementation of AA to keep the animals healthy and productive. However, under ideal (normal) situation increasing crude protein level will compromise gut health in that, the fermentation of extra AA produces toxic metabolites that will enhance the growth and proliferation of pathogenic microbes. Therefore, low crude protein-AA diet is recommended under healthy conditions.
Dr. Alemu, I think your considerations are consistent with those we did earlier. This consistency is more evident in his report that, in conditions of low health challenge, it is feasible to use diets with a lower level of crude protein. The reason for adopting this practice would be precisely related to the fact that healthy animals have less demand for non-amino acids. essential and that the relationships between essential amino acids and the lysine proposed in the ideal protein for the animal category would be more adjusted to their requirements. These facts are based on our report presented above.
Dr. Kazem, according to some information in the literature, the increase in energy demand to meet the animals' immune response to the challenge is not very significant and does not need, in principle, alteration.
Dear Sirs!
I am opposed to singling out the concept of any "most important" nutrients, including amino acids. Perhaps, when we determine the need for a certain substance, we can take the productivity of animals as a standard criterion. In another case, if there are problems, for example with health, we should review the norm of need. That is, this does not mean that the addition of an amino acid to the feed is a productivity stimulant. This may be due to the fact that the conditions have changed and therefore you need to adjust the rate (increase). In other cases, this may be due to a change in the criterion (parameter) for determining the optimal rate of nutrient demand.
If for some reason there are challenges from the gut, then the need for amino acids will change and not proportionally in all – this has been explained in a number of works.
Let's imagine the metabolism as a chain of interconnected links. What is the "most important" link? If any link is destroyed or weakened, the entire chain will suffer.
Returning to the work under discussion, I note that it is important and interesting, but the results should be evaluated from a different perspective
Valeriy Kryukov, I understand your considerations and agree with your views. It turns out that the objective of the work was to review, among other possibilities and implications, such as the use and metabolism of some amino acids by intestinal cells, are influenced by enteric diseases and some specific amino acids in the diet. I think that the authors do not have the vision, that the adjustments in the levels of some amino acids would be sufficient or the most important to get around the problem. However, they would reveal the need to adjust these specific amino acids, as one of the consequences resulting from the metabolic changes of the challenge. The reason for choosing the amino acids in the study, I imagine, is due to its high correlation with meat deposition in the carcass and consequently with the feed efficiency of the chickens, which are the main factors that define the profitability of production. So I understand, that the article is consistent with what you said, that the conditions have been changed and, therefore, it is necessary to adjust the rate (increase), in this case the amino acids. And that if, for some reason, there are challenges in the intestine, the need for amino acids will change and not proportionally to the whole. Finally, I would like to emphasize that in our view the question of being main is also relative. and variable according to the type of challenge. I inform you that I am not part of the work team, and that the authors may or may not disagree with my points of view. I make these considerations because I understand that we are in the discussion forum on the matter presented here.
Thanks for the great topic and content. Some doubts arise during the paper reading, it would be better to increase CP digestibility by reducing the antinutritional and allergenics, using ingredients like SPC (Soybean Protein Concentrate), or decrease CP by using "pure AA" to meet the regular requirements. A second question, regarding soluble fiber, would be better to reduce soluble fiber or take the ratio between Soluble and Insoluble fiber into consideration? Sometimes when reducing crude fiber, we are also reducing insoluble fiber. Regarding mucin production, some papers have shown that once reduced antinutritional and allegenics like Glycinin and Conglycinin, the epithelium has a different morphology, increasing length and crypt depth. That suggests a higher demand for Threone, Proline, and other AAs.
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