Effects of microbial phytase on growth and mineral utilisation in broilers fed on maize soyabean-based diets
1999
Zanini, S.F. | Sazzad, M.H.
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 2 x 2 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.
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