98 Buttiauxella Phytase Improves Growth Performance of Weanling Pigs Fed Corn, Soybean Meal, and Canola Meal Based Diets

Abstract

Abstract An experiment was conducted to test the hypothesis that a Buttiauxella phytase expressed in T. reesei can compensate the reduction in standardized total tract digestible (STTD) P, Ca, digestible energy (DE), and standardized ileal digestible (SID) AA in diets for pigs without impaired growth performance. A positive control diet (PC) was formulated to meet the requirement for STTD P and total Ca (0.33% STTD P and 0.60% Ca). A negative control diet (NC) was formulated with 0.18% STTD P and 0.45% Ca and with reduction of DE by 43 kcal/kg and SID AA by 0.01–0.02% vs. PC. Adding 250, 500, or 1,000 phytase units (FTU) per kg to the NC diet for a total of 5 experimental diets formulated three additional diets. A total of 155 pigs (BW: 8.77 ± 1.38 kg) were allotted to the 5 treatments, and there were 8 replicate pens per treatment. The experiment was conducted for 21 d. Pigs were weighed at the beginning and conclusion of the experiment, and daily feed allotments were recorded. Average daily gain (ADG), average daily feed intake (ADFI), and gain: feed ratio (G:F) were calculated for each treatment. Data were analyzed using contrast statements to compare PC and NC, PC and phytase, and to determine linear and quadratic effects of phytase. Results indicated that pigs fed the NC diet had reduced (P < 0.05) ADG and G:F compared with pigs fed the PC diet (Table 1). Adding phytase to NC increased ADFI (linear, P < 0.05) and ADG (quadratic, P < 0.05) with the greatest values for the 1,000 FTU treatment. Including phytase in the diet also resulted in a quadratic increase (P < 0.05) in G:F. In conclusion, Buttiauxella phytase may be included in diets with reduced nutrients and energy for weanling pigs without compromising pig growth performance.