Bioavailability and poultry fecal excretion of phosphorus from soybean-based diets supplemented with phytase

Bianca Almeida Brandão Martins,Ricardo De Albuquerque,Simi Luiza Durante Aflalo Robassini,Laura Maria De Oliveira Borgatti,Luiz Waldemar De Oliveira Souza

doi:10.1590/s1516-35982013000300005

Bianca Almeida Brandão Martins, Ricardo De Albuquerque + Show 3 more

Open Access

https://doi.org/10.1590/s1516-35982013000300005

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Abstract

Five hundred and four 1-day-old Cobb broiler chickens were randomly allotted to 18 treatments and fed a semi-purified basal diet (4 g/kg total phosphorus) supplemented with 2 levels of supplemental P (0.5 or 1 g/kg) during 21 days to evaluate performance and bone mineralization; to assess the relative bioavailability of P (RBP) in wheat meal (WM) and roasted (RS) or extruded soybean meal (ES), with or without phytase (0 or 750 ftu/kg diet), using dicalcium phosphate (DC) as standard; and to estimate phosphorus excretion. Weight gain (WG), feed intake (FI), feed to gain ratio (FG), and tibia ash weigh (AW) were assessed. For each source, the RBP was calculated by the slope ratio method, when tibia ash weight was regressed on P ingested. Ingested and fecal P was determined to calculate P intake, and P excretion and excretion rate. Phytase addition increased overall FI, WG, and FG ratio by 3.3, 2.6 and 0.8%, respectively, but differences were not significant. Overall AW was increased by 10.8% after the enzyme inclusion in the diets. The relative bioavailability of phosphorus values of tested WM, RS, and ES were increased by 6.32, 64.32, 76.99%, respectively, in response to supplementation of phytase in diets containing WM, RS, and ES, respectively. Phytase reduced P excretion by 12.7% and the excretion rate by 15.0%, regardless of the phosphorus source or level.

Highlights

The main characteristics of the modern poultry production are total confinement and high density, resulting in great reject output containing nitrogen, phosphorus and others
Five hundred and four 1-day-old Cobb broiler chickens were randomly allotted to 18 treatments and fed a semi-purified basal diet (4 g/kg total phosphorus) supplemented with 2 levels of supplemental P (0.5 or 1 g/kg) during 21 days to evaluate performance and bone mineralization; to assess the relative bioavailability of P (RBP) in wheat meal (WM) and roasted (RS) or extruded soybean meal (ES), with or without phytase (0 or 750 ftu/kg diet), using dicalcium phosphate (DC) as standard; and to estimate phosphorus excretion
Diets not supplemented with phytase showed some light enzymatic activity (Table 2) probably due to the natural enzyme contained in vegetal ingredients, especially the wheat meal diets, which presented higher endogenous phytase activity

Summary

Introduction

The main characteristics of the modern poultry production are total confinement and high density, resulting in great reject output containing nitrogen, phosphorus and others. Broilers fed 0 or 750 ftu/kg of diet ingested similar amount of ration regardless of the P source or level, indicating that phytase did not influence feed intake (P>0.01), as reported in the literature.

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