Effectiveness of an experimental consensus phytase in improving dietary phytate-phosphorus utilization by weanling pigs.
Consensus phytase is a new biosynthetic, heat-stable enzyme derived from the sequences of multiple homologous phytases. Two experiments were conducted to determine its effectiveness, relative to inorganic P and a mutant enzyme of Escherichia coli phytase (Mutant-EP), in improving dietary phytate-P availability to pigs. In Exp. 1, 36 pigs (3 wk old, 7.00 +/- 0.24 kg of BW) were fed a low-P corn-soybean meal basal diet plus consensus phytase at 0, 250, 500, 750, 1,000, or 1,250 U/kg of feed for 5 wk. Plasma inorganic P concentration, plasma alkaline phosphatase activity, bone strength, and overall ADG and gain:feed ratio of pigs were improved (P < 0.05) by consensus phytase in both linear (R2 = 0.20 to 0.70) and quadratic (R2 = 0.30 to 0.70) dose-dependent fashions. In Exp. 2, 36 pigs (4 wk old, 9.61 +/- 0.52 kg BW) were fed the basal diet + inorganic P at 0.1 or 0.2%, consensus phytase at 750 or 450 U/kg of feed, Mutant-EP at 450 U/kg of feed, or 225 U consensus + 225 U Mutant-EP/kg of feed. Pigs fed 750 U of consensus phytase or 450 U of Mutant-EP/kg feed had plasma inorganic concentrations and bone strength that fell between those of pigs fed 0.1 or 0.2% inorganic P. These two measures were 16 to 29% lower (P < 0.05) in pigs fed 450 U of consensus phytase/kg of feed than those of pigs fed 0.2% inorganic P. Plasma inorganic P concentrations were 14 to 29% higher (P < 0.05) in pigs fed Mutant-EP vs. consensus phytase at 450 U/kg at wk 2 and 3. In conclusion, the experimental consensus phytase effectively releases phytate P from the corn-soy diet for weanling pigs. The inorganic P equivalent of 750 U of consensus phytase/kg of feed may fall between 0.1 and 0.2%, but this requires further determination.
Gentile
J M
JM
Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.
Roneker
K R
KR
Crowe
S E
SE
Pond
W G
WG
Lei
X G
XG
D010832:6-Phytase / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D001682:Biological Availability; D001842:Bone and Bones / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000201:enzymology; D009753:Nutritive Value; D010758:Phosphorus / Q000097:blood; D016226:Phosphorus, Dietary / Q000008:administration & dosage / Q000493:pharmacokinetics*; D010833:Phytic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013552:Swine / Q000254:growth & development* / Q000378:metabolism; D014886:Weaning; D015430:Weight Gain / Q000187:drug effects
D016226:Phosphorus, Dietary; D010758:Phosphorus; D010833:Phytic Acid; D000469:Alkaline Phosphatase; D010832:6-Phytase