Effects of Dietary Standardized Ileal Digestible Isoleucine:Lysine Ratio on Nursery Pig Performance
Published:March 2, 2021
Summary
Introduction The inclusion of crystalline amino acids in swine diets is an effective strategy to not only meet specific nutritional requirements, but also reduce diet cost and environmental impact. Typically, amino acids are expressed in ratio to lysine (Lys) for diet formulation process. Thus, it is important to evaluate essential amino acids in a Lys deficient scenario to appropriately ident...
Dr Mike Tokach, I congratulate the study team for the work done. Considering that although the inclusion of synthetic isoleucine in pig diets is currently unfeasible due to price and availability, determining its relationship with lysine is essential to enable the use of synthetic valine available on the market, with a compatible price. Even though I understand the relevance of the study, I would like to make some considerations: - It would not be interesting to include in the tables the values of essential amino acids versus non-essential amino acids. In this case, non-essential amino acids also important for piglets such as glutamine and aspartate should not be included. : - I have my convictions, that I am studying to establish the relationship of a certain amino acid with lysine, in the experimental diets the level of digestible lysine should be suboptimal. This would avoid the possibility of an excessive consumption of lysine, which could underestimate the ratio of the evaluated amino acid. As I am aware of Dr Tokach's experience and knowledge, I make my considerations in order to assess their consistency. With my thanks.
A few items that we consider in formulating diets for these experiments. We make sure we are below the lysine requirement by conducting lysine titration trials in the same facility with same pigs prior to doing the ratio studies. We formulate to a maximum SID Lys:CP ratio to provide enough nitrogen for synthesis of nonessential amino acids and add non-essential amino acids (glycine and glutamine) to increase nitrogen (CP) if needed. We also check that any other essential amino acid is provided at the higher end of requirement estimates relative to lysine to make sure the test amino acid is first limiting.
Dr. Mike Tokach, I appreciate the prompt clarification of the issues raised. However, I would like to point out that there was a mistake regarding the composition of the rations. The question remains, in the rations described there is the inclusion of ac. glutamic, not glutamine, as reported. I understand that glutamine would really be more appropriate, due to the supply of the amide group, important in the formation of nucleotides, which are fundamental for cell multiplication in the intestinal mucosa. I continue with the thought, that precisely due to the purpose of inclusions of glutamate or glutamine?, It is that the relationship of essential AAS with non-essential AAS should be included in the composition of the rations. I think this highlight is important ..
Juarez Donzele Sorry, yes we used glutamic acid as the N source instead of glutamine with the glycine. The purpose was to provide a N source and not a functional amino acid. Thus, we used glutamic acid. L-glutamine is also not allowed to be used in all locations in the U.S. at this time. Studies have shown that glycine and another amino acid can be used to provide the N needed in low CP diets. I do not disagree that the glutamine may provide other benefits.
I suggest that we discontinue using the term “nonessential amino acids” for glutamate, glutamine and glycine. These three amino acids are nutritionally and physiologically essential for pigs and poultry, particularly for the health and function of their small intestine. Let’s call these amino acids “functional amino acids” in animal nutrition. Please see Wu, G. 2018. Principles of Animal Nutrition, CRC Press.
Both glutamate and glutamine can be used for animal feeding if they are approved for this purpose by the State Chemist Office of a state in the U.S. and If glutamate and glutamine are produced by the U.S. state that has granted the approval. Texas is among many U.S. states that have approved the use of glutamate and glutamine for animal feeding.
For an update on glutamate and glutamine nutrition in swine, the following paper may be of interest to you all.
Hou, Y.Q. and G. Wu. 2018. L-Glutamate nutrition and metabolism in swine. Amino Acids 50:1497-1510. https://pubmed.ncbi.nlm.nih.gov/30116978/
Wu, G., F.W. Bazer, G.A. Johnson, D.A. Knabe, R.C. Burghardt, T.E. Spencer, X.L. Li, and J.J. Wang. 2011. Important roles for L-glutamine in swine nutrition and production. J. Anim. Sci. 89:2017-2030.
I am pleased to share the following link to an issue of papers on amino acids in nutrition and health: companion, zoo and farm animals for Adv Exp Med Biol.
https://www.springer.com/gp/book/9783030544614
One paper entitled "Amino Acid Nutrition and Metabolism in Chickens" in this issue is an Open Access article freely available to the public. Here is the link: https://link.springer.com/chapter/10.1007/978-3-030-54462-1_7
I am also pleased to share the following links at CRC Press and Amazon to the 2nd edition of my new book "Amino Acids: Biochemistry and Nutrition" (CRC Press 2021):
CRC Press Link: https://www.routledge.com/Amino-Acids-Biochemistry-and-Nutrition/Wu/p/book/9781032030890
Amazon link: https://www.amazon.com/Amino-Acids-Biochemistry-Nutrition-Guoyao/dp/0367552787
I hope that this new book will be helpful for your teaching, research, and animal feeding practices.
I agree completely with Dr. Tokach as far as he went. In real production programs, most protein sources are fairly expensive and are often unbalanced in their amino acid supply. Even if they are not the "major" amino acids we must be aware of making a severe effort to establish and maintain not only the supply but the balance of amino acids --particularly in the monogastric.
I also agree with Dr. Tokach's considerations. But my point was that the use of glutamine as a source of nitrogen would be more efficient than glutamate, due to the metabolism of glutamine in the piglet's intestinal mucosa, in addition to producing the glutamate itself, it also provides the N of the amide group which is fundamental in the production of nucleotides that is used for cell multiplication in the intestinal mucosa. I also understand that the supply of glycine, not only by the supply of N but also has an action on the animal's immune system. It is an important source of N for the piglet. I would also like to clarify that my suggestion to include the relationship between essential AAs and non-essential AAs, would be to make it clear that this relationship is adequate. This is because sources of N can be included equaling the protein level, without this relationship being adequate. I made these clarifications to make it clear that I did not disagree with what was presented, I simply made some considerations that I thought were important.
Both glutamate and glutamine are major energy sources for the small intestine of pigs. The pig’s small-intestinal mucosa has a limited ability to synthesize glutamine from glutamate but actively converts glutamine into glutamate via glutaminase. So, for the small intestine of pigs, glutamine can replace glutamate but the vice versa. Both glutamate and glutamine have their important functions beyond serving as substrates for protein synthesis in the small intestine.
.Guoyao Wu
I did not make use of the suggested thermology, simply to avoid further discourse, since the non-essential name is more in the domain of the scientific milieu. However, I fully agree that the classification of these three amino acids, as functional amino acids, is more appropriate, mainly due to their actions maintaining the integrity of the intestinal mucosa of birds and swine.
Best Regards
Juarez Donzele Thanks for your helpful comment. It is the time to use the updated term in our discussion so that we all recognize the nutritional and physiological roles of functional amino acids, as well as their practical applications in animal production.
Dr Guoyao Wu, I continue with the opinion that glutamine has an additional advantage over glutamate, but understanding that glutamine only constitutes an energy source for the swine mucosa after its conversion to glutamate. It turns out that in this conversion, glutamine is discouraged, releasing nitrogen as the amide group, which is used in the production of nucleotides. These elements are fundamental for cell multiplication. This detail, in my opinion, makes glutamine an amino acid more limiting than glutamate for the intestinal mucosa. Because of its differentiated importance for the intestinal mucosa, it is that glutamine constitutes the only amino acid that the mucosa removes from the arterial circulation. So we have two sources of glutamine for the mucosa, that of the diet and that acquired from the circulation. For your acknowledged knowledge of the metabolism of amino acids, I would appreciate your opinion regarding my considerations
Juarez Donzele In the pig small intestine, glutamine is a major metabolic fuel but glutamine also has many other important functions, as explained in my JAS paper.
Juarez Donzele In 1994, we found that the small intestine of pigs extracted glutamine but not other amino acids (including glutamate) from the arterial blood.Thus, it is true that the mucosa of the small intestine received two sources of glutamine: the diet and blood. This is very different from glutamate. It is glutamine but not glutamate that is used for the synthesis of nucleic acids in animal cells (including intestinal mucosal cells). At present, glutamine is more expensive than glutamate. Therefore, a proper ratio of glutamine and glutamate can be cost-effective for improving the integrity and function of the small intestine of pigs, particularly under stress conditions, such as weaning and heat stress.
Wu, G., A.G. Borbolla, and D.A. Knabe. 1994. The uptake of glutamine and release of arginine, citrulline and proline by the small intestine of developing pigs. J. Nutr. 124:2437-2444.
Wu, G. 1998. Intestinal mucosal amino acid catabolism. J. Nutr. 128:1249-1252.
Guoyao Wu Thank you for the kindness of the information. I fully understand that the mixture of the two amino acids (GLUTAMINE + GLUTAMATE) is a matter of price, since glutamate can be produced in the intestinal mucosa from glutamine. There would be no need for its inclusion.
It is certain that amino acids modulate the immune system via General controlled nonrepressed (GCN2). The quantity of amino acids but above all the composition of the amino acid profile activate or repress the immune response. The BCAA amino acids, especially leucine, activate mTOR and repress GCN2, thereby increasing the inflammatory process in the intestine, which is of particular importance in weaning pigs.
https://www.frontiersin.org/articles/10.3389/fimmu.2017.01719/full?utm_source=S-TWT&utm_medium=SNET&utm_campaign=ECO_FIMMU_XXXXXXXX_auto-
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