Effect of supplementing phytase to corn- or wheat-based gestation and lactation diets on nutrient digestibility and sow and litter performance

Effect of an Escherichia coli derived, 6-phytase on nutrient digestibility and sow and litter performance were investigated. Six (exp. 1) or eight (exp. 2) sows per diet were randomly assigned to a positive control (PC), a negative control (NC) with reduced non-phytate phosphorus (P), NC + 500 FTU kg(-1), or NC + 1000 FTU kg(-1) diet from day 60 of gestation to day 22 postpartum. Diets in exps. 1 and 2 were based on corn and wheat, respectively. Energy, N, calcium (Ca), and P digestibilities were determined between days 73 to 77 (Period 1), 104 to 106 (Period 2) of pregnancy, and days 16 to 20 postpartum. Sow and litter performance were monitored. During gestation, phytase at 500 FUT kg(-1) did not affect nutrient digestibility in exp. 1 but improved (P < 0.05) DE and digestibilities of DM, energy, N, and P in exp. 2. Increasing phytase to 1000 FTU kg(-1) reduced (P < 0.05) digestibilities of energy and N (exp. 1). In both experiments, digestibilities of N, Ca, and P were higher (P < 0.05) in period 2 than period 1. During lactation, supplementing the NC diet with 500 FTU kg(-1) only improved (P < 0.05) DE and Ca and P digestibility in exp. 1 and DE and digestible P in exp. 2. Compared with NC, P digestibility and digestible P were higher (P < 0.05) in the NC + 1000 FTU kg(-1) diet in both experiments. Sow and piglet performance was unaffected by diet in both experiments. In conclusion, P digestibility was greater between days 104 and 106 of gestation than between days 73 and 77 of gestation and phytase improved P digestibility during lactation but this effect was not consistent during gestation in both experiments.