Effects of microbial phytase on growth and mineral utilisation in broilers fed on maize soyabean-based diets.
1. A 3-week feeding trial with 96 sexed d-old broiler chickens was conducted to examine the effects of microbial phytase supplementation (Natuphos 5000) at 2 dietary energy concentrations on their performance, and the utilisation of nitrogen (N), phosphorus (P), calcium (Ca) and zinc (Zn) and on tibiae ash, Ca, P and Zn concentrations. Four replicate pens (6 birds per pen) of a completely randomised design were used in a 2x2 factorial arrangement of treatments with 2 contents of metabolisable energy (11.72 and 12.55 MJ ME/kg) and 2 additions of phytase (0 and 500 U of microbial phytase/kg). 2. Phytase supplementation significantly improved the utilisation of N, P, Ca and Zn (as a percentage of intake) and increased the concentration of Ca and Zn in the tibiae (P<0.05) because of higher intakes of dry matter, N, P, Ca and Zn. Phytase also significantly reduced the amount of P in the excreta (P<0.05). 3. The AME content of the diet influenced significantly (P<0.05) the excretion of N, P, Ca and Zn and the concentration of P and Ca in tibiae with the birds fed on the high AME diet excreting more minerals and having a smaller percentage of these minerals in their tibiae. However, there were strong interactions between phytase addition and AME in tibia ash and P, with the phytase supplementation producing a higher ash content at the higher AME a and a lower P content at the lower AME.
Zanini
S F
SF
Department of Animal Science, Veterinary School, Federal University of Minas Gerais, Brazil.
Sazzad
M H
MH
D000818:Animals; D002118:Calcium / Q000032:analysis; D002645:Chickens / Q000254:growth & development* / Q000378:metabolism*; D004032:Diet; D002149:Energy Intake; D008903:Minerals / Q000378:metabolism*; D010755:Organophosphates / Q000032:analysis; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D013025:Glycine max; D013977:Tibia / Q000737:chemistry; D015430:Weight Gain; D003313:Zea mays; D015032:Zinc / Q000032:analysis
D008903:Minerals; D010755:Organophosphates; D010744:Phosphoric Monoester Hydrolases; C400321:3-phytase; D015032:Zinc; D002118:Calcium