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Effect of reducing dietary mineral content on growth performance, water intake, excreta dry matter content and blood parameters of broilers

Lookup NU author(s): Dr Nemat Ziaei, Dr Jonathan Guy, Emerita Professor Sandra Edwards



The objective of this study was to investigate whether it is possible to reduce phosphorus (P) excretion by feeding a lower level of dietary P than that currently recommended, without compromising welfare, and whether this is sensitive to the level of dietary calcium (Ca). 2. A randomised complete block design was used with a total of 224 1-d-old male chicks of a commercial genotype in two batches. Chicks had a 10-d adaptation period. After this, they were moved to cages and allocated to one of 4 dietary treatments (4 and 3 birds per cage in batch 1 and 2, respectively). A standard level of Ca and P (83 and 66 g/kg, respectively) was compared with three lower levels of Ca (73, 63 and 53 g/kg) all at the same reduced level of P (55 g/kg). Records were made of live weight of birds on an individual basis and feed and water consumption on a cage basis. Every 7 d, the dry matter (DM) content of a sample of mixed excreta from each cage was measured. Birds were slaughtered and samples taken for analysis of plasma mineral content, retention of N, Ca and P and tibia bone strength. 3. The initial reduction in dietary mineral level did not adversely affect performance or bone strength. However, decreasing dietary Ca level below 73 g/kg, at constant P, led to reduced feed consumption and bone strength. Dietary treatment had no significant overall effect on water intake, water : feed ratio, excreta DM content, Ca and P retention or metabolisability of DM. There was no significant correlation between mean plasma Ca or P level and DM content of rectal digesta. 4. In conclusion, reducing dietary P from 66 to 55 g/kg to reduce potential environmental impact of broiler production had an adverse effect on bird welfare when the level of Ca was reduced below 73 g/kg, as a result of decreased feed intake in the early growth period and reduced skeletal strength.

Publication metadata

Author(s): Ziaei N, Guy J, Edwards S, Blanchard P, Ward J, Feuerstein D

Publication type: Article

Publication status: Published

Journal: British Poultry Science

Year: 2008

Volume: 49

Issue: 2

Pages: 195-201

Print publication date: 01/03/2008

ISSN (print): 0007-1668

ISSN (electronic): 1466-1799

Publisher: Taylor & Francis


DOI: 10.1080/00071660801953238

PubMed id: 18409094


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