Phosphorus equivalency value of a commercial phytase in weaner pigs

The aim of the current study was to evaluate the efficacy of Ronozyme HiPhos (DSM Nutritional Products Ltd.) in the immediate post weaning period and to determine the equivalency value of this phytase relative to P. A total of 568 mixed sex pigs were weaned at 26.3 ( ± 1.01, SD) d of age and an average weight of 7.9 ( ± 1.51) kg. Pigs were offered 1 of 8 diets. Diets were fed from weaning for a period of 3 wk and consisted of a negative control diet (NC) containing 0.5 % P, the NC diet + 0.05 % P, NC diet + 0.10 % P, NC diet + 0.15 % P, NC diet + 0.20 % P; and the NC diet + 500, 1,000, or 2,000 units of phytase FYT per kg. Increasing dietary P had no effect on ADFI or ADG, however it did improve G:F quadratically (P < 0.05). Increasing levels of dietary phytase tended to increase ADG (linear, P = 0.056) and linearly improved G:F (P < 0.05). Increasing dietary P or adding phytase improved apparent total tract digestibility (ATTD) of P (linear, P < 0.001; quadratic, P < 0.05) and Ca (linear, P < 0.001; quadratic, P < 0.01). In conclusion, phytase was effective in improving performance and improving P and Ca ATTD of pigs during the immediate post weaning period. Based on ATTD of P, 500 FYT of phytase /kg was equivalent to the addition of 0.088 % of P in weaner pig diets.