2 commentslast update:Oct 19, 2012

Phytases and phytases

Ioannis Mavromichalis, PhD International Consulting Nutritionist, Ariston Nutrition SL
Undoubtedly, the most successful enzyme for pigs is phytase. At least, this is evidenced by the commercial records for this enzyme, and the plethora of available phytases in the market.


But, although having such a great range of similar products to select from is certainly a good thing, it does create a problem. Namely, which one to pick?
There are many criteria, ranging from price to stability, from effectiveness to safety for human handlers, etc. I am sure we can come up with a lengthy list!
In my work, I have seen my customers ranking price, effectiveness, and stability as the three most important aspects.
I would be interested to read your views on how you select a phytase enzyme, what criteria you use, and why. Please, do leave a comment!


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    Dr Nikolaos Kotrotsios

    Pork producers have traditionally had to add phosphorus rich ingredients to the diet but undigested phosphorus passes through the pig and enriches manure thus leading phosphorus will accumulate in the soil. For this reason adding phytase of microbial origin to pig diets increased the availability of phosphorus and reducing the amount of phosphorus that must be added to the diet. However the breakdown of phytate in the large intestine is of little value to the pig because there is little absorption of phosphorus once the digesta leaves the small intestine. There are a variety of commercially available phytases that are approved for use. At this moment the orientation of the product selection must be the economical reasons for example phytase and DDGS have to be priced appropriately to achieved savings. However, I would like to focus in some critical points that have included the manufacturing process characteristics and the environmental sensitivities. The position in which the dephosphorylation occurs affect the efficacy of the phytase and its potency at various pH levels. Because, phytase exists as a complex with magnesium, pH is an important issue. The solubility of phytase increases as pH declines. It is generally recommended that the Ca:P ratio should be closed to 1:1 in order to maximise the success of phytase use. Also the use of high levels of zinc is contraindicated when phytase is being used. So the specific recommendations and release values to avoid over or underestimations of phosphorus release from phytase source, then the diets must be properly balanced, less phosphorus passed through the pig undigested and therefore the quantity of phosphorus in the manure is reduced. At the other point should take in consideration the ability of the phytase enzyme to increase the availability of nutrients other than the phosphorus. If the addition of phytase is been expected to increase energy and aminoacids then should reformulate pig diets. Finally, the heat stable when exposed to higher heat temperatures during manufacturing pelleting feeds must be critical selection among similar products.

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