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Efficiency of microbial phytases in diets formulated with different calcium:phosphorus ratios supplied to broilers from 35 to 42 days of age

2015; Taylor & Francis; Volume: 44; Issue: 1 Linguagem: Inglês

10.1080/09712119.2015.1091324

0974-1844

Luciana de Paula Naves, Paulo Borges Rodrigues, Camila Meneghetti, Verônica Maria Pereira Bernardino, David Henrique de Oliveira, Mariana Masseo Saldanha, Levy do Vale Teixeira, Luziane Moreira dos Santos,

Trace Elements in Health

The aim of this study was to investigate the efficiency of six microbial phytases (named of A to F) supplemented in diets (1500 FTU/kg) formulated with three different calcium:available phosphorus ratios (3.5:1.0, 5.0:1.0 and 6.5:1.0). Moreover, one positive control diet without phytase that was formulated with a calcium:available phosphorus (Ca:AP) ratio of 6.5:3.0 was also considered. The utilization of dietary nutrients, as well as the bone, plasma and performance parameters of broilers from 35 to 42 days of age was evaluated. Phytase D increased the P and magnesium plasma concentrations. Broilers fed diets containing phytase B showed a lower feed intake and weight gain, while the birds fed diets containing phytase E consumed more feed, gained more weight and excreted less total P. The highest Ca retention and also the best nitrogen utilization were determined when the diet contained phytase D or E. For all phytases evaluated, an increased in the dietary Ca:AP ratio increased the tibia ash content and the Ca balance. Phytase utilization reduced the phytate P excretion, improving its utilization by the broilers. For the rearing period evaluated, it is possible to reduce the AP of the diet to 1.0 g/kg when Ca is maintained at 6.5 g/kg, and the diet is supplemented with 1500 FTU of phytase A, B, C, D or E/kg. This diet allows the maintenance of performance, optimizes the bone mineralization, and it improves the Ca, total P, phytate P and nitrogen utilization in addition to reducing the P excretion.