Nutrient utilization and manure P excretion in growing pigs fed corn-barley-soybean based diets supplemented with microbial phytase

• Published in: Animal science journal Vol. 80; no. 1; pp. 19 - 26
• Main Authors: Emiola, A.(University of Manitoba, Winnipeg (Canada)), Akinremi, O, Slominski, B, Nyachoti, C.M
• Format: Journal Article
• Language: English
• Published: Melbourne, Australia Blackwell Publishing Asia 01.02.2009; Blackwell Publishing Ltd
• Subjects: 6-Phytase - administration & dosage; Animal Feed; Animal Husbandry; Animal Nutritional Physiological Phenomena; Animal sciences; Animals; Calcium - metabolism; CERDO; CRECIMIENTO; CROISSANCE; DIET; DIETA; Dietary Supplements; DIGESTIBILIDAD; DIGESTIBILITE; DIGESTIBILITY; Digestion - drug effects; Digestion - physiology; Enzymes; EXCRECION; EXCRETION; FISIOLOGIA DE LA NUTRICION; FITASA; FOSFORO; Glycine max; GROWTH; Hogs; Hordeum; Manure; Manures; Nitrogen - metabolism; nutrient utilization; Nutrients; NUTRITION PHYSIOLOGY; NUTRITIVE VALUE; PHOSPHORE; PHOSPHORUS; Phosphorus - metabolism; PHYSIOLOGIE DE LA NUTRITION; PHYTASE; pigs; PORCIN; REGIME ALIMENTAIRE; SWINE; VALEUR NUTRITIVE; VALOR NUTRITIVO; Zea mays
• ISSN: 1344-3941; 1740-0929
• DOI: 10.1111/j.1740-0929.2008.00590.x

ABSTRACT The effect of high levels of microbial phytase supplementation in diets for growing pigs was studied in a 2‐week performance and nutrient digestibility trial involving 28 growing pigs weighing 16.4 ± 1.06 (mean ± SD) kg. Seven corn‐barley‐soybean meal‐based diets consisting of a positive control (PC) formulated to meet or exceed NRC nutrient requirements; a negative control (NC) with non‐phytate P reduced by 0.1% unit from NRC requirement and fed without or with 500 or 1000 U/kg; a doubled negative control (DNC) with no added inorganic P and fed without or with 2000 or 4000 U/kg. Chromic oxide was added as an indigestible marker and all diets were fed as mash. Pigs fed the PC diet had a higher P digestibility compared with those fed the NC (P < 0.02) and the DNC (P < 0.001) diets. Supplementing the NC diet with pyhtase tended to improve P digestibility (P < 0.10). However, addition of phytase to the DNC diet resulted in linear (P < 0.001) and quadratic (P < 0.03) increases in P digestibility with an overall improvement of 8% and 121% at 4000 phytase U/kg of diet, respectively, compared with the PC and DNC diets. Apparent total tract digestibility of N, OM and DM were higher (P < 0.05) in the PC diet compared with the DNC diet, but not the NC diet (P < 0.10). No effect of phytase addition to NC was observed on Ca, N, DM and OM digestibility. Phytase addition to the DNC diet resulted in a linear increase (P < 0.05) in N, DM and OM digestibility but not Ca. Increasing the levels of phytase supplementation in the NC and the DNC diets linearly decreased fecal P (P < 0.05) content by 45 and 42%, respectively. Adding phytase at 1000 or 4000 U/kg increased P retention (P < 0.05) by 14.3 or 15.6% units, respectively, compared with the PC diet. Urinary P excretion was higher in the group fed the PC diet compared with those fed the NC and DNC diets (P < 0.05). The results of this study show that complete removal of inorganic P from growing pig diets coupled with phytase supplementation improves digestibility and retention of P and N, thus reducing manure P excretion without any negative effect on pig performance.