Future of Amino Acid Evaluation in Poultry Nutrition

A very clear and effective summary of different descriptions of amino acid digestibility.

As a team, Evonik personnel are intimately involved in amino acid nutrition, and I have a few questions / points.

1. You comment "...Digestibility of AA represents portion of total dietary AA that is enzymatically hydrolyzed, fermented by digestive tract microbes and absorbed from gastrointestinal lumen..." I assume you would subtract those AAs lost to microbial fermentation; they are effectively removed from host animal utilisation
2. Are you completely happy that Rooster assays accurately measure AA digestibility in young broiler? We have big reservations.
3. Table 2. Our estimates of AA digestibility in Canola / Rapeseed meal are considerable lower than those shown in Table 2 (for Soya, close agreement). Field experience tells us that Rapeseed meal is a less effective amino acid source.
4. Table 3. Very interesting comparison of heat damaged DDGS digestibilities. Any comment on mechanism of reduced digestibility, in particular for Methionine?
5. Kluth and Rodehutscord (2006); you comment on a lack of difference in digestibility of soya and rape for both broiler and turkey. Again, this is unexpected...

Thankyou

MPS