The Role of Amino Acids in the Immune System – A special focus on broilers.
Published:May 24, 2019
Summary
A study published in 2003 comparing the nutrition and genetics of broilers from 1957 to a commercially available broiler strain estimated that within less than 50 years of development, broilers were reared to maturation in a third of the time (Havenstein et al., 2003). This shows clear evidence that improvements in genetics, nutrition and management of rearing meat producing chickens has continua...
Congratulations on the article, considering the importance of the revised article. I take this to reaffirm some points that I mentioned earlier. Based on the information contained in this review, it can be perfectly deduced that, in practice, the reduction in feed crude protein, which is based on the ratio of essential amino acids to lysine, is the ideal protein for the animal category in question, can be questioned. This is because the information that underlies these ideal protein proposals is usually obtained under conditions of lower immune challenge than the field environment. Thus, amino acid ratios in the ideal protein need to be readjusted according to the farm's degree of challenge. Another aspect, not least, is the fact that some nonessential amino acids, such as glutamine, glutamate and glycine, among others, become semi-essential in conditions of increased immune challenge. Thus, the reduction of the protein level by decreasing the concentrations of these amino acids in the diet may compromise the development of birds.
Many thanks for all the kind and thought provoking comments!
@Prof. Donzele, I agree that other the immune system requirements for other 'non-essential' amino acids should also be considered (as my review was already rather lengthy this was not really covered). This is definitely a topic to investigate further when formulating diets for challenging conditions.
For Rose, my point is that your work has shown that reducing crude protein in feed is not as simple as it may seem. This is because factors such as immune challenge and environmental stress, such as high temperature, are factors that alter the relationships of some essential amino acids with lysine, highlighting the dynamic character of the ideal protein. This detail reveals that in order to obtain the best result of animal performance it is necessary to make adjustments in the feed according to the immunological and thermal challenge conditions of each farm. In the case of non-essential amino acids, the considerations were also to highlight the possible restrictions to be considered due to the reduction of feed crude protein.
Oscar Briceño these are excellent questions! I must admit these details are still largely unknown. As the immune response is specific to different stressors, (e.g. heat stress vs necrotic enteritis vs respiratory virus infections) the ideal nutrient requirements for a bird exposed to those stressors is likely also varied.
To answer these questions we must focus research to understanding the specific needs of the bird for both growth and immune function when faced with each of these individual challenges. In my opinion a long term aim for precision nutrition will not only be identifying nutritional needs for a 'healthy' vs 'sick' animal, but will be precise enough to design diets that are most efficient for hot climates, vaccine programs, and specific disease occurrences.
I hope to be publishing more of these primary research studies soon and look forward to the ongoing discussion.
In my opinion, one of the most important role of amino acids, especially Arginine and Methionine (L,DL) is helping the immune system in broilers. As you know, methionine is one substrate for Glutathione synthesis. Cys, GABA, Glu and Gln and some other amino acids are very important in this topic.
Universidad ISA (Instituto Superior de Agricultura)
13 de octubre de 2019
Dear Dr. Rose, in my opinion, the nutritional requirements reported by genetic companies are for healthy and stress-free animals and the ideal protein profile may vary in the order of limiting amino acids, for example, an animal challenged with enteritis may have a higher threonine requirement. For the main component of the intestinal mucosa and a viral disease can increase the needs of arginine, glutamine and others. The nutritional requirements of an animal depend on its sanitary conditions (healthy or sick) and stress.
Universidad ISA (Instituto Superior de Agricultura)
16 de octubre de 2019
Amin, as an example, when I do a consulting to a poultry or swine company, before designing the diets by productive stages, I evaluate the challenge that it has: viral, bacterial, fungal (mycotoxin) or parasitic (coccidia, tapeworm or worm), then evaluate the low, medium or high challenge level, then increase the nutritional requirements recommended by the genetic house in a range of 0 to 5% or greater.
Joaquin Armando Paulino Paniagua this is excellent information. For the moment we still do not have exact requirements for all essential amino acids in all the different conditions. This is obviously a lot of scenarios and nutrients to test so it will be some time before we can have very specific answers. I like your approach to ensure there are no limitations in essential amino acids while these specifics are still being identified.
Joaquin Armando Paulino Paniagua Curious how this works out for your customers. It's my undertanding from the literature that overfeeding of amino acids to try and overcome immune related performance losses in a research setting has actually increased those loses. It's been a few years (10 or so since I looked inot this), but the idea at the time was that the extra amino acids exerted an additional metabolic toll to be dealt with, and that this created problems that exacerbated the problems caused by the acue phase response, and ultimately more birds died.
Are there specific amino acids you up-spec, or do you essentially bring them all up by an increased AID Lysine content, and maintain the normal ratios to Lysine??
Mohammad Hosein Shahir I couldn't agree more, but unfortunately don't have the answer. As I have also responded below, there is really a lack of dedicated research to look at BCAAs in broiler nutrition as it pertains to immune function. I hope there is more in the field for us to review soon.
Hossien Mohammadzadeh thanks for your question, it is an excellent one! I say this as I still have the same question as you pose here. I was hoping to include more information on the BCAAs in this article however, the information for broiler immune function related to leucine supplementation levels is really limited. Hopefully more research is conducted to elucidate the specific need of BCAAs when the immune system is stimulated, that can help us understand this question better.
Dr. Rose Whelan, excellent review, not only for the review but also for the subject matter presented. This review has some fundamentals that I have been discussing on several occasions here at Engormix. One of them is the fact that the nutritional requirements of birds are normally carried out in environments with less immunological challenge, compared to the environment of birds in field production systems.
It has been shown, as I have stated on other occasions, that this is one of the reasons that the nutritional requirements established may not meet the requirements of birds in the field. Thus evidencing the dynamic character of the ideal protein. It can also be deduced from the review, that the reduction of crude protein with supplementation of essential amino acids, which is made based on the ideal protein of the animal category, may not meet the demand of birds.
Juarez Donzele Hi Prof. Donzele, thanks again for your comments. They are relevant and interesting, as always. I agree that the ideal protein ratio is dynamic. Understanding amino acid requirements in these conditions will allow us to utilize low crude protein diets, while being assured that supplementation of the essential amino acids is not limiting. For this reason, I also see a high value in conducting nutrient requirement research in non-optimal environments (i.e. environmental stressors, pathogen challenges etc.)
Universidad ISA (Instituto Superior de Agricultura)
27 de julio de 2020
Dr Rose when an animal is stressed or challenged goes from normal metabolism to inflammation and immunometabolism the order of the amino acid requirements can vary because the requirements of a healthy animal are different from the requirements of the immune system and the order of the requirements is different example if the pathogen is an enteric bacterium it is different from a respiratory infection for the requirements of the immune system, the precursor amino acids of glucoses or glycogenics are priority for the immune system after fats.
Informative discussion, thanks to all who have contributed.
To anyone:
In NAE production when dealing with NE challenged birds due to perhaps too aggressive cocci cycling from an vaccine which Amino Acids become more important and in what order and perhaps a small explanation as to why?
Where can I get more information about it and also research papers to read.
Thanks in advance for the answer.