155 Efficacy of a Bacterial 6-Phytase on Apparent Total Tract Digestibility of Nutrients and Retention of Phosphorus of Nursery and Growing Pigs

Abstract

Abstract This study was conducted to determine the efficacy of a bacterial 6-phytase on apparent total tract digestibility (ATTD) of nutrients and retention of phosphorus (P) in nursery and growing pigs. In experiment (Exp.) 1, twelve barrows (initial BW of 8.5 ± 0.3 kg) were individually housed in metabolism crates and were allotted based on a quadruplicate 3 × 3 Latin square design with three treatments and three periods. In Exp. 2, twelve barrows (initial BW of 35.7 ± 1.9 kg) were individually housed in metabolism crates and were allotted following the same experimental design of Exp. 1. The dietary treatments were: positive control (PC): a diet formulated meeting nutrient requirements from NRC (2012); negative control (NC): a diet 0.14% deficient in the Ca and P requirements; and a diet with bacterial 6-phytase at 500 FTU/kg of feed (PHY; Rovabio PhyPlus, Adisseo, France). Each period lasted for eight days, and consisted of a 4-day adaptation period and a 4-day collection period. All pigs were weighed at the end of each period to adjust daily feed allowance. Chromium oxide, at 0.5%, was added as an external marker indicating the start and end of fecal collection. Urine and fecal samples were collected daily and stored until further chemical analysis. Data from both experiments were analyzed using the MIXED procedure of SAS 9.4. Treatments were considered fixed effects, and the individual pig and period were included as random effects. In both experiments, the ATTD of Ca and P, and P retention in PC were greater (P < 0.05) compared with NC. Supplementation of bacterial 6-phytase improved (P < 0.05) ATTD of Ca (45 to 57%) and P (31 to 45%) and P retention (31 to 43%) in nursery pigs, and ATTD of P (44 to 55%) and P retention (42 to 54%) in growing pigs. No differences were detected on the ATTD of DM and CP of nursery and growing pigs among the treatments, and on nitrogen (N) retention for growing pigs. In conclusion, the supplementation of a bacterial 6-phytase improved the ATTD and retention of P in nursery and growing pigs. Results from both experiments indicated that the supplementation of a bacterial 6-phytase in diets for nursery and growing pigs can be a potential alternative to reduce the high levels of inorganic P sources, whereas still increasing the digestibility and utilization of P by nursery and growing pigs.