emily

I think everyone in this discussion made good comments. It seems to me that all that is needed is an underlying theory to fit all the various pieces into. This is the same for phytase and all the other enzymes: First, it should be accepted that responses to enzymes follow Michaelis-Menten kinetics. Enzymes do not give linear responses. This was very nicely illustrated by Shirley and Edwards, Jr. ( ...

Hello all,From the point of view of enzyme activities, the standard measure is how many moles of the product (the result of the chemical reaction) is released by a specific amount of the enzyme during a specific time and pH conditions. Although I am a biotechnologist I have worked in the animal industry and know that information does not translate well with industrial enzyme users. However, in the ...

Lode Nollet that is precisely my point. An FTU is a totally useless measurement of how one phytase may compare to another. we have run numerous trials with different phytases and have often reported this.

Park W. Waldroup yes this is because FTU is measured at a pH of 5.5 in the method, while the phytase needs to work at lower pH levels. so any phytase which has a pH optimum at 2-4 will have a high activity but might have a lower FTU analysed at pH 5.5 compared to a phytase which has a pH optimum at around 5.5 but much lower activity at pH 2 to 4.

in our many studies involving numerous phytase products, it seems like the term FTU is totally meaningless. supposedly 500 FTU from phytase A should be equal to 500 FTU from phytase b but seldom is.

Good job; the value of feed enzyme as pro-nutrient feed additive is well, perhaps better quantified by growth perfromance and mechanisticaaly so by digestibility. The ability to find and evolve the next generation of feed enzymes will be driven by understanding of target substrates and the implications to the animal nutrition. However, the gut is populated with diverse assemblage of microbiota (bi ...

The reality - in my view- is that results with other enzymes different than Phytases are VERY equivocal. It is so for many reasons including: 1. Lack of precise info on feed substrate for the enzyme2. Poorly estimated energy values for ingredientes and formulas 3. Inter brand enzyme activities comparison today is close to impossible: units are completely different. 4. It is not certain if "purifi ...