PSII-14 - Effect of a consensus bacterial 6-phytase variant (PhyG) on energy and amino acid digestibility and the impact on production performance in pigs

Abstract: Phytase is commonly used in pig feed to improve the availability of phosphorus (P) and other minerals such as calcium (Ca) and sodium (Na). However, a phytase that can break down phytate quickly and completely in the early gut, can also reduce the anti-nutritional effect of phytate, resulting in an improved amino acid (AA) and energy digestibility. Recent studies demonstrated that a consensus bacterial 6-phytase variant (PhyG) consistently improved apparent ileal AA digestibility (meta-analysis of 8 datasets) and ileal energy digestibility in pigs (meta-analysis of 4 datasets). Application of digestible AA and energy matrix for phytase alone, or in combination with other enzymes, can reduce the feed cost and improve pig production benefits. This concept has been tested in 3 studies including one study in piglets and two studies from weaning to slaughter. In Exp. 1, three treatments were tested including a nutritionally adequate positive control (PC) and 2 PhyG-supplemented diets, reduced in digestible P, Ca, Na, net energy and digestible AA vs. PC, based on the contribution of PhyG added at 1,000 or 2,000 FTU/kg, respectively. The data showed that the application of full matrix could maintain or improve piglet performance and lead to up to 5.5% reduction in feed cost per kg body weight gain. In 2^nd Exp., weaned pigs were randomized to 4 treatments and fed test diets in 5 phases, from weaning until market weight. Treatments included: a nutritionally sufficient positive control (PC) and 3 test diets with PhyG alone at low or high dose (phased dosing in different phases), or PhyG at low dose in combination with xylanase–β-glucanase (XB). All test diets were formulated with application of full energy and nutrient matrix. Overall growth performance (from weaning to slaughter) in all enzymes supplemented diets with full matrix application, was maintained or improved compared to PC, and there was a reduction in feed cost per kg body weight gain by up to 5.8%. In the third experiment, weaning pigs were randomly distributed to 3 treatments corresponding to a control diet, a PhyG treatment with diets supplemented with 1500 FTU/kg of PhyG, and a third treatment supplemented with the same PhyG dose and a multi-enzyme (Xylanase, β-glucanase, Amylase, and Protease). The enzyme supplemented diets were formulated with corresponding matrix values. Application of full energy and nutrient matrix for phytase alone or in combination with a multi-enzyme maintained the performance and carcass yield and quality of pigs from weaning to slaughter, leading to feed cost savings. In summary, the application of digestible AA and energy matrix, in addition to mineral matrix, can reduce feed cost and improve pig production benefits.