Maria Aparecida Melo Iuspa

Dear Prof. Juarez Donzele,Regarding Guanidine Acetic Acid (GAA), Formation each mole of GAA consumes a mol of Arg and a mol of Gly. Then supplementation diet with GAA can save some Arg and Gly but any way GAA needs to be methylated by a methyl donor like Met to form Creatine, therefore supplementation diet with GAA may not help suboptimal diet with SAA.

Dear Prof. Donzele. Please be aware that creatine content of all forms of animal byproducts is EXTREMELY variable; C of V for fish meal approaches 100%. Whilst we do indeed need to progress to a situation where we define an actual creatine requirement for all classes of vertebrate livestock, reliance on animal byproducts should account for this extreme variability. MPS

Further to this comment. I often do costing and training exercises looking at the impact of NOT using supplemental amino acids in commercial diets. Every time - in every situation - addition of a methionine source results in the highest cost saving and the highest reduction in crude protein content. As methionine is first-limiting amino acid in poultry feeds, this is not altogether surprising.Of c ...