Gene Pesti

Anyone wanting to understand the nutrition of methionine and related compounds could start with a book by Vincent duVigneaud. It is a wonderful read for anyone interested in how biochemistry and nutritional sciences developed together and anyone wanting to understand sulfur and methyl nutrition. After you have studied it, the Chamruspollert dissertation will make more sense. There are plenty of ex ...

I think the issues are much more complex than any of these papers suggest. You may be interested in papers by Marissa Chamruspollert. I think her dissertation is available on line. Below is a little AI summary I just got through Google. The rather small "plateau" before toxicity from GAA is particularly interesting in that similar responses have been seen from nutrients involved in methyl metaboli ...

@luciano Pinotti And dietary protein level. Since methyl groups are required for creatine and uric acid synthesis, nitrogen balance is also a factor. A very important one, I think. Young chicks depositing most of their amino acid intake into body protein should require many fewer labile methyls for uric acid synthesis. Us old roosters in net nitrogen balance oxidize all our amino acid intake. For ...

@Ana Gavrau Thanks for the invite, but I have seen several "biological" farms in France and they are very nice. I could not tell how happy their chickens were, but I'm not a specialist in that area. I do know that there are some breeds that appear much more content and docile in cages than others. Those are the ones I would choose to work.

@Ana Gavrau Thank you. First, I don't think animals producing urea should ever be compared to those producing uric acid, which requires methyls in its synthesis.I don't understand your comment "It is also important to mention that "organic" means also better housing conditions, than conventional industrial production". Chickens are socialists at heart. The vast majority will lay around in front of ...

It is hard to evaluate much of the data in this area because there are so many factors involved. In my early work we were not controlling folic acid levels, a mistake. I am glad that one of my students and I were the ones that figured it out. Wheat products can contain up to 4000mg/kg betaine. Animal products and most other plant products have some. Corn and soy have none that we could detect. At ...

@Antônio Mário Penz Junior I think this is an area where modern data analyses collection and modeling techniques will be particularly helpful. Temperature, body size and egg output all influence how much energy the hens need to stay slim, but not too slim. There were some excellent equations developed in Brasil a few years ago that should be particularly helpful. If we believe weather forecasts we ...

@Gene Pesti OOPS! I meant to say the starch for normal and waxy corns are different. Waxy corn is grown specifically for making corn starch and does not dent. That is the reason corn gluten meal, a by-product of starch production has a different amino acid profile from normal corn. We occasionally found non-dent corn in commerce and assumed it had been rejected by CGM manufacturers. Or maybe too m ...

@Antônio Mário Penz Junior For sure! Starch from normal corn is the same as starch from waxy corn, etc. we could go on all day. The gross energy and digestibility and absorption as birds age for each ingredient can be measured. Then computer modeling can help get the right combination of ingredients for each situation. I'm just guessing that the companies selling amylase should be happy to determi ...

@Antônio Mário Penz Junior Absolutely! I hope some young people looking for important research areas to develop read your comments.