One phytase product claims an advantage in heat processing; the other claims an advantage in efficacy. Is one better than the other?

Unit for unit, the spelling is different, but the two most popular phytase products base enzyme activity on the same standard of measurement.

Natuphos, marketed by BASF Animal Nutrition, is measured in FTUs. The product is made from Aspergillus niger fungi and is a 3-phytase, meaning the phosphates are released from the phytate beginning at the carbon-3 of the inositol ring. The product is active over a wide range of pH from 6.5 to 5.5.

Ronozyme P, marketed by Roche Vitamins Inc., is measured in FYTs, after the Danish spelling of phytase. It is produced using the organism Peniophora lycii and is a 6-phytase product. Ronozyme is active over a narrower pH range, with an optimum of 4.5.

Regardless of the source, phytase research shows optimum supplementation of 227 units of phytase per pound of feed replaces about 0.1% available phosphorus in a corn-soybean meal ration.

Phytase lowers the phosphorus excreted in manure by releasing the phytate-bound phosphorus found naturally in grains and soybeans. Like poultry, swine lack sufficient intestinal phytase. By adding the enzyme to the diet, more phosphorus becomes available to the animal, which lowers the amount of supplemental phosphorus required and the amount that goes undigested. About 11 to 12 lb. of inorganic phosphorus can be substituted with 0.4 lb. of phytase product per ton of feed.