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Dernière mise à jour : Mai 2018

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What « requirements » for essential amino acids in broiler chickens ? A critical survey of their determination and of some practical models

INRA Prod. Anim., 17(1), 19-34.


1 Institut Technique de l’Aviculture, Service Technique, 28 rue du rocher, F-75008 Paris

2 CIRAD-EMVT, Service d’Alimentation Animale, TA 30 / A, Campus de Baillarguet, F-34398 Montpellier cedex 05
3 INRA, Station de Recherches Avicoles, F-37380 Nouzilly


To balance the feed levels in essential amino acids,nutritionists use tables containing average requirementsstemming from bibliographical surveys. Result ofexperiments studying essential amino acid requirements,depend both on the criterion to be optimized(growth rate or feed efficiency) and on the methodologyadopted for analysing the results. From an experimentto the other, environmental conditions andchicken genotype may also explain a part of the observedvariability of the requirements. To cope with thisvariability, the results from numerous experimentsobtained mainly in fast growing broilers raised underoptimal conditions are pooled but the results of thosegrouped analyses are not precise, and this impairs theapplication of measured amino acid requirements tofield conditions. Mechanistic models integrating basicknowledge of the energy and protein metabolism mightconstitute additional tools to quantify the effects of anessential amino acid level on broiler performancesunder different conditions. Models not only synthesisethe knowledge acquired by various experiments butalso take simultaneously into account the multipleinteractions among factors of variation. There aresome marketed models measuring the effects of themain feed characteristics (essential amino acids, energyetc.) and raising conditions on chicken growth.Their results seem precise enough for an applicationbut they are presented as "black boxes" and the complexitiesof their functioning make them difficult toupdate. INAVI is a model fully open to the user thatmight be more adapted to the diversity of productionsystems. Prediction of the growth of the chicken byINAVI is based on the effects of environmental andnutritional factors on feed intake regulation.

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