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Nutrient utilization and manure P excretion in growing pigs fed corn‐barley‐soybean based diets supplemented with microbial phytase
Author(s) -
EMIOLA Adewale,
AKINREMI Oluwole,
SLOMINSKI Bogdan,
NYACHOTI C. Martin
Publication year - 2009
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1111/j.1740-0929.2008.00590.x
Subject(s) - phytase , soybean meal , chemistry , zoology , nutrient , phosphorus , chromic oxide , meal , excretion , manure , animal feed , food science , biology , agronomy , biochemistry , raw material , organic chemistry
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.