Tryptophan requirement of 22 to 34-week-old caged-laying hens

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February 21, 2020
Dr Mike, for a better understanding of the work, I would like to ask you to kindly inform us what was the relationship between methionine + digestible cystine with the digestible lysine used in your diet to assess the level of tryptophan. With my thanks
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Mike Persia Mike Persia
Associate Professor
February 25, 2020

Juarez Donzele,

Great question, this experiment was a classical requirement experiment so both D Lys and D SAA were supplied in excess of the hens requirements so that Trp would be the limiting nutrient for egg production.

Mike.

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February 25, 2020

Dr. Mike, I appreciate your prompt reply. In this case, the tryptophan requirement must be established in grams/day, making no reference to its relationship with lysine. Do I think correctly?

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Mike Persia Mike Persia
Associate Professor
February 26, 2020
Juarez Donzele

Yes that is correct.
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February 25, 2020
Dr Mike, I forgot to point out that due to carelessness, I am absolutely sure, the use of the isomer D of lysine in the feed of the birds was mentioned, which certainly did not occur. This is because, as you know, lysine in this isomer is not used by birds. Even methionine, I believe it must have been used as a mixture of D and L (DL) isomers. Carelessness like this happens quite often.
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February 26, 2020

Dear Juarez Donzele, I have to admit that I haven't followed the entire discussion herein but noticed the statements on D-isomers of amino acids. Indeed, the nutritional value of D-Lys (and others) is very limited in farm animals and therefore all supplemental amino acids - except methionine - are available as L-isomer only. Methionine indeed behaves different and as the D-isomer of methionine is highly, if not completely, available as building block to farm animals, the racemate of D- and L-methionine has become the gold standard in animal nutrition. Moreover, even if given as D-methionine only, transformation into animal performance is as effective as with L-Met. BR Andreas

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Mike Persia Mike Persia
Associate Professor
February 26, 2020
Dr. Andreas Lemme

In this case D is my short hand for digestible Lys or digestible Met, not the l or d form of the amino acid. Sorry for the confusion.

Best regards,
Mike
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February 26, 2020
To Drs Andreas and Mike, for the experience and professional competence of the authors, I have no doubt that the restrictions we made on the article are fully known to you. What really happened was a carelessness in the preparation of the matter, which can occur with any .
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Dr Valeriy Kryukov Dr Valeriy Kryukov
Doctor in Biological Sciences
April 15, 2020
Dr. Andreas Lemme
Indeed, DL-Methionine has received a wide and recognized distribution. However, the fate of the D isomer is not well understood.
I established 30 years ago in an experiment on broilers that DL-Methionine induces cytochrome P-450, which is responsible for the metabolism of foreign compounds in the body. This fact explains the decrease in the toxic effect of aflatoxin on chickens.
In General, DL-methionine will "unexpectedly" affect a number of processes in the body for those who do not know about the induction of cytochrome P-450. The effectiveness of drugs, cholecalciferol and a number of other additives in feed.
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OGUNWOLE, OLUGBENGA OGUNWOLE, OLUGBENGA
BSc Hons MSc PhD
April 17, 2020
Dr Valeriy Kryukov This is a profound contribution which served to reverberate the cardinal roles of methionine in detoxification of toxins in vivo. I only want to add that the sentence be modified to indicate that cytochrome P-450 is one of the veritable means of such metabolism of foreign compounds except perhaps there are no alternative metabolic paths. This contribution is an apt contribution and an impetus to upcoming scientist with interest in methionine metabolism
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April 21, 2020
Dr.OGUNWOLE, OLUGBENGA Yes, it is, but there is another explanation. Methionine is not direct detoxicant. But (similar to betaine) it plays important function in liver methylation cycle and protect liver cells against osmotic stress. Thus, it protect liver hepatocytes and makes better methabolic condition for hepatocytes cytochrome-P 450. So, direct detoxication enzyme is P-450 oxidase, and direct anti toxin molecule is oxygen.
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April 22, 2020
Valeriy Kryukov, interesting and important for your information regarding the specific action of D-Methionine in the induction of cytochrome P450. In this case, in regions with a high incidence of mycotoxin in the feed ingredients, especially corn, the efficiency of the use of DL-Methionine by birds should not be greater than that of L-Methionine. This considering, farms with low level of health challenge, with limited use of drugs. Is this reasoning correct?
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Dr Valeriy Kryukov Dr Valeriy Kryukov
Doctor in Biological Sciences
April 22, 2020
Just the opposite! DL, methionine induces P-450. As a result, Cytochore p-450 increases the detoxification of mycotoxins
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July 18, 2020
Dr Valeriy Kryukov, I believe that I was not understood, because what I deduced was exactly what the Lord stated as correct, However, your consideration is that my deduction would not be correct
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