Effect of dietary phosphorus, calcium, and phytase on performance of growing turkeys.
Female and male turkeys were fed 110, 73, 52, and 30% of the NRC (1994) nonphytate P (NPP) requirement without and with 500 phytase units (FTU)/kg during 4 to 14 or 16 wk of age, respectively. At 110% P (control; also 110% of NRC Ca), phytase was without effect. At 73% of NPP (100% Ca), without phytase, performance was similar to the control; with phytase, performance was equivalent, and in some stages, superior to the control. At 52% of NPP (90% Ca), performance was inferior without phytase and was variably similar or poorer than the control with phytase. At 30% NPP without phytase, poults gained poorly and showed a high incidence of leg disorder at 8 wk when they were removed from experiment; poults gained better with 80% NRC Ca compared with 110%. At 30% NPP with phytase, turkeys performed remarkably well, although suboptimally, at 80 or 110% NRC Ca. Phytase at 400, 300, and 200 FTU/kg with increasing age periods performed as well as 500 FTU/kg with 73% of NRC NPP (100% Ca) and 52% NRC NPP (90% Ca). These lower phytase levels were not as sufficient as 500 FTU/kg with 30% of NRC NPP; this inadequacy was more severe with higher dietary calcium. Phytase was effective in reducing dietary P requirements of growing turkeys when the NPP levels were below NRC (1994) requirements.
Atia
F A
FA
Department of Animal Production and Fisheries, Suez Canal University, Ismailia, Egypt.
Waibel
P E
PE
Hermes
I
I
Carlson
C W
CW
Walser
M M
MM
D010832:6-Phytase / Q000008:administration & dosage* / Q000494:pharmacology; D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002136:Calcium, Dietary / Q000494:pharmacology*; D005260:Female; D008297:Male; D009752:Nutritional Status; D016226:Phosphorus, Dietary / Q000494:pharmacology*; D014422:Turkeys / Q000254:growth & development*
D002136:Calcium, Dietary; D016226:Phosphorus, Dietary; D010832:6-Phytase