Phytase and Amino Acid Availability

The effect of microbial phytase on true and apparent ideal amino acid digestibilities in growing-finishing pigs. Fifteen kilogram barrow fitted with cannulas at the ileo-cecal junction were fed a semi-purified corn starch and soybean meal-basal diet formulated to contain 3.4 Mcal digestible energy per kilogram, 17.0% crude protein, 0.8% calcium and 0.6% phosphorus (0.13% phytate-phosphorus). The basal diet was supplemented with either 0 or 1,000 units of microbial phytase per kilogram. Biological samples and digestibilities were determined three times at four week intervals starting when the pigs were seventy days of age. Pigs fed phytase-supplemented diets excreted less phosphorus in the feces (P=0.003) and more in urine (P=0.001), however, total phosphorus excretion was similar to pigs fed diets without phytase supplementation. Phytase additions to the semi-purified diet did not affect the apparent ideal digestibility or on true ideal digestibility of nitrogen or on most amino acids. The researchers reported that apparent ideal digestibility of arginine and methionine were increase by phytase supplementation.

Pomar, C. and co-workers. 2008. The effect of microbial phytase on true and apparent ideal amino acid digestibilities in growing-finishing pigs. J. Animal Sci. Epublished on March 28.