PSVIII-5 - Harvesting pigs with Phytase and no inorganic Phosphorus! Is that possible?

Abstract: The trial examined if a novel phytase from a bacterial consensus 6-phytase variant expressed in Trichoderma reesei could replace all added inorganic phosphate (P) in a diet with reduced Ca, digestible P (dP), digestible amino acids, and net energy fed to commercial pigs from 19 kg body weight (BW) until slaughter, while maintaining performance and carcass quality parameters. The corn and soybean meal-based diets used nutrient requirements from National Swine Nutrition guide (2010). Four treatments were tested in a completely randomized design with 9 replicate pens (8 mixed sex pigs/rep): 1) positive control (PC), 2) negative control (NC) without inorganic P, (nutrient difference equated to a1000 FTU/kg matrix versus the PC), 3) NC + 500 FTU/kg (500); 4) NC + 1000 FTU/kg (1000). Mash diets were fed ad libitum in 6 phases: nursery 3 (0-10 days), grower 1 and 2 (10-30 days), finisher 1 and 2 (30-78 days), and finisher 3 (78-115 days). As NC and NC+phytase were at native dP% levels, lameness was expected. When 25% of the pigs in a treatment showed lameness, diet dP was adjusted; this only occurred in NC and 500 groups. Data analysis used ANOVA with mean separation via Tukey honest significant difference with P< 0.05%. Results showed equivalent ADG, BW, ADFI, loin area and fat at 12^th rib for PC and 1000 units phytase/kg feed in swine raised to market age. 500 units improved ADG, BW and ADFI versus the negative control. Coefficient of variation (CV) on BW responded in parallel with BW, the lowest CVs were seen for PC and 1000 with intermediate improvement for 500 versus NC. These results show that 1000 units/kg feed of this novel phytase alleviated performance loss in a no added P diet versus the diet without phytase and match that of PC (with inorganic P added).