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A comparative evaluation of functions for partitioning nitrogen and amino acid intake between maintenance and growth in broilers

Kebreab, E., France, J., Kuhi, H. D. and Lopez, S. (2008) A comparative evaluation of functions for partitioning nitrogen and amino acid intake between maintenance and growth in broilers. Journal of Agricultural Science, 146. pp. 163-170. ISSN 0021-8596

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To link to this item DOI: 10.1017/s0021859607007423

Abstract/Summary

The results from three types of study with broilers, namely nitrogen (N) balance, bioassays and growth experiments, provided the data used herein. Sets of data on N balance and protein accretion (bioassay studies) were used to assess the ability of the monomolecular equation to describe the relationship between (i) N balance and amino acid (AA) intake and (ii) protein accretion and AA intake. The model estimated the levels of isoleucine, lysine, valine, threonine, methionine, total sulphur AAs and tryptophan resulting in zero balance to be 58, 59, 80, 96, 23, 85 and 32 mg/kg live weight (LW)/day, respectively. These estimates show good agreement with those obtained in previous studies. For the growth experiments, four models, specifically re-parameterized for analysing energy balance data, were evaluated for their ability to determine crude protein (CP) intake at maintenance and efficiency of utilization of CP intake for producing gain. They were: a straight line, two equations representing diminishing returns behaviour (monomolecular and rectangular hyperbola) and one equation describing smooth sigmoidal behaviour with a fixed point of inflexion (Gompertz). The estimates of CP requirement for maintenance and efficiency of utilization of CP intake for producing gain varied from 5.4 to 5.9 g/kg LW/day and 0.60 to 0.76, respectively, depending on the models.

Item Type:Article
Refereed:Yes
Divisions:Faculty of Life Sciences > School of Agriculture, Policy and Development
ID Code:8773
Uncontrolled Keywords:METABOLIZABLE ENERGY-INTAKE, YOUNG CHICKS, ADULT ROOSTER, REQUIREMENTS, EFFICIENCY, ACCRETION, PROTEIN, TURKEYS, CARCASS, ISOLEUCINE

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