Digestible lysine requirements of male broilers from 1 to 42 days of age reassessed
Published:March 20, 2019
Summary
Introduction Lysine (Lys) is the second limiting amino acid (AA) in practical corn-soybean meal diets. Growth performance and proper muscle development of broiler chickens is highly dependent of an adequate dietary supply of Lys. Although all AA coded in the nucleic acid sequence are required for muscle protein synthesis, also depending on its frequency and dietary supply, Lys is the main...
Congratulations to the team for the study conducted. However I had some doubts as follows. In the elaboration of the experimental diets I do not think the best option to use the other essential amino acids in the requirement of the birds. I believe it is more appropriate to ensure that the levels of the other amino acids are at least in the proper relation with the highest level of lysine evaluated in each phase. This is because, if the levels of the other essential amino acids used, the ratio falls below that recommended in the ideal protein for the study category, the estimated lysine level may not correspond to the real value. Another consideration to be made is the interdependence of the phases, that is, in the study corresponding to the period of 12 to 28 days, the birds should receive the best level of lysine determined in the study of 1 to 12 days. .
Juarez Donzele you raised a valid question, ideal amino acid profile play a vital role in growth. I have a little bit of confusion and think you will make it clear: say I'm following ideal profile but only lysine goes high, what will be fate of additional lysine? Either it will disturb the profile or only required level will play a role and additional allowance will withdraw.
While formulating a diet for broiler I have the practice to use additional Lysine as if Lysine is deficient in diet all other amino acids will be in extra mode and these amino acids crossing the ideal profile cannot play a role, but if lysine levels are only high, only lysine will be some extra, other amino acids will play their role. 2nd thing: lysine is most heat labile amino acid, if we supply some additional lysine what will be its effects?
Thank you for this study, which is truly objective. Just would like to know if methionine is an essential factor that acts directly on the role of the lysine.
Dr. Menad, certainly not only methionine but all essential and non-essential amino acids must be in the animal's demand, so that maximum efficiency in the use of lysine can be obtained. This is because, in the deficiency of any of the essential amino acids as well as inadequate ratio of essential amino acids to non-essential amino acids, by compromising protein deposition it interferes by compromising the metabolic use of lysine.
I'm very interested in everything that has to do with mineral and vitamin supplements and, since you are specialized in nutrition, I appreciate your help in keeping me informed of all that is new.
In any experiment looking at dose response to a single nutrient, all other nutrients need to be maintained at a level where they do not impact on performance parameters being investigated. Obviously if this is not the case, results obtained may be due to deficit of another nutrient, rather than that being studied. In this case, all SID AA levels were maintained at a level expected to be sufficient for the age range being studied. The same goes for that other crucial nutrient, energy.
Adding additional lysine to a diet where another nutrient (eg methionine) is limiting will not result in additional performance improvements. As lysine is almost exclusively utilised in protein deposition, excess will have to be excreted, with a net negative impact on energy utilisation for growth.
Martin Smith thanks for your kind response and making me understand the confusion.
you make it clear that extra allowence of lysine will nt be fruitful instead it will impact negatively on energy metabolism.
Regards
Greetings, Martin. Would you have the updated tables of the requirements in each one of the species of those amino acids, please? alexiscoronell@hotmail.com
Dr. Aslam, in my understanding not only lysine, but any amino acid supplied above the requirement of the animal or in inadequate proportion, in the case lysine questioned, will be catabolised by reducing the net energy of the diet.
Thanks to all of you. Just a quick question: when can methionine or lysine be used as a primary limiting factor? Or can they be replaced by a raw material?
Very important information for practitioners.
Unfortunately, the authors replace the concept of "Lys intake" with the concept of "technical parameters of feed", for example: Lys requirements at 0.933, 0.963, 0.911, and 0.925% for BWG, FCR, carcass yield, and breast meat yield.
The main thing is the Lysine intake g/d. Technical parameters are derived and may depend on the composition of feed.
The article is called: Digestible lysine requirements of male broilers ...", but the emphasis is on the recommended technical parameters of feed. This substitution of concepts creates errors in thinking when developing norms of need. The need is g / head / day.
