Age-related changes in mineral retention and excretion in starter and finisher pigs diets with and without exogenous phytase

Abstract

Male castrated DanBred hybrid pigs were subjected to five balanced feeding experiments designed to assess
changes in nitrogen, phosphorus, and calcium consumption as a function of age. Optiphos and Natuphos,
two commercially available phytase preparations, were used at a concentration of 0.01%. There was a
statistically significant increase (P<0.05) in both the quantity of nitrogen consumed by the body and the
amount of nitrogen excreted in urine as individuals aged. Additionally, the overall nitrogen production was
greater. Over time, there was a marked decline in nitrogen retention. This trend persisted even after phytase
was added to the diet. Feeding phytase increased phosphorus uptake by 28% to 34% while decreasing total
production by 38% to 45%. As pigs aged, their indigestibility of calcium reduced and their feces production
increased. When comparing the effects of Optiphos and Natuphos, no statistically significant difference was
found.