92 Effects of Increasing Dose of a Novel E. coli Phytase on Total Tract Digestibility of Minerals and Energy in Pigs

Abstract

Abstract The objective was to test the hypothesis that an increasing dose of a novel thermostable 6-phytase that was derived from E. coli and expressed in a Pichia Pastoris yeast (Superphy; Hanley International, LLC, Belmont, MA) increases apparent total tract digestibility (ATTD) of minerals and energy by pigs. Forty-eight barrows (initial weight: 22.61 kg) were housed in metabolism crates and fed 6 diets based on corn and soybean meal. The positive control (PC) diet contained P at the requirement. The negative control (NC) diet contained no feed phosphate, but contained 0, 250, 500, 1,000, or 2,000 phytase unit/kg. Feces were collected for 4 d after 5 d of adaptation. Dried and ground fecal samples were analyzed for dry matter, energy, Ca, P and other minerals. Data were analyzed using a model that included diet as fixed variable and contrast statements were used to compare PC and NC diets and to demonstrate linear and quadratic effects of phytase. Results indicated that ATTD of dry matter and energy and concentration of digestible energy in NC without phytase were greater (P < 0.05) than in PC, but ATTD of ash, K, Mg, Na, Cu, Fe, Mn, and Zn was not different between the 2 diets. There was no effect of phytase on ATTD of dry matter and energy or on digestible energy in diets. As dietary phytase increased, ATTD of ash and Mg increased (linear, P < 0.05) and ATTD of Ca and the standardized total tract digestibility (STTD) of P also increased (quadratic, P < 0.05), but ATTD of K, Na, Cu, Fe, Mn, and Zn was not affected by phytase. In conclusion, the novel enhanced E. Coli based phytase increased ATTD of Ca, P, and Mg and STTD of P if included in a diet containing Ca and P below requirements.