Growth performance, bone measurements, and P digestibility in nursery pigs fed diets supplemented with increasing levels of a new bacterial 6-phytase expressed in Pseudomonas fluorescens

Abstract Text: An experiment was conducted to determine the effects of a new bacterial 6-phytase expressed in Pseudomonas fluorescens (CIBENZA^® PHYTAVERSE^®, Novus International, Inc., St Charles, MO) on the growth performance, bone parameters, and P digestibility in nursery pigs. A total of 280 pigs (initial BW = 6.25 ± 1.03 kg) were randomly allotted to 1 of 5 treatments with 14 replications and 4 pigs/pen. Treatments included 1) a positive control (POS) that met requirements (NRC, 2012) for all nutrients, 2) a negative control (NEG) deficient only in standardized total tract digestible (STTD) P (-0.18% vs. POS), 3) NEG supplemented with 500 FTU/kg phytase (NEG+500), 4) NEG supplemented with 1,000 FTU/kg phytase (NEG+1000), and 5) NEG supplemented with 2,000 FTU/kg phytase (NEG+2000). Data were analyzed using the mixed procedure (SAS^® Institute, Cary, NC). Orthogonal polynomial contrasts were used to determine linear and quadratic effects of increasing levels of phytase. ADG, ADFI, and G:F were greater (P < 0.01) in POS fed pigs than in NEG fed pigs. The ADG was improved (linear and quadratic, P < 0.01) from 0.308 (NEG) to 0.475 (NEG+2000) kg as phytase supplementation level increased. Likewise, ADFI and G:F were also improved (linear and quadratic, P < 0.01) by increasing levels of phytase. Bone ash and bone P content were greater (P < 0.01) in pigs fed POS vs. pigs fed NEG (1.159 and 0.215 g vs. 0.557 and 0.101 g, respectively). As phytase supplementation increased, bone ash and P weight also increased (linear and quadratic, P < 0.01) compared with NEG fed pigs. Bone ash and P weight in pigs receiving NEG+2000 were not different (P > 0.05) from that of pigs receiving the POS diet (1.106 and 0.192 g vs. 1.159 and 0.215 g, respectively).Phytase supplementation improved (linear and quadratic, P < 0.01) the STTD of P from 17.31 (NEG) to 70.74% (NEG+2000). Results from this experiment demonstrated the efficacy of this new 6-bacterial phytase to improve growth performance, bone traits, and the STTD of P. 

Keywords: bone, pig, phytase