Ileal amino acid digestibility assays in poultry: Case for a universal approach. (Short communications)

Publikations-Art

Kongressbeitrag

Autoren

Ravindran V, Adeola O, Rodehutscord M, van der Klies JD, Acamovic T, Bryden WL, Nyachoti M, Rostagno H, Lemme A.

Erscheinungsjahr

2009

Veröffentlicht in

17th European Symposium on Poultry Nutrition. Proceedings & Abstracts

Seite (von - bis)

192 (SC3.8)

Tagungsort

Edinburgh (Scotland)

Tagungsdatum

23.-27.8.2009

Schlagworte

amino acid digestibility, Broiler, endogene Verluste

Describing the available amino acids in feed ingredients in terms of digestible amino acids is clearly superior to total amino acids. Broiler responses to diets containing less-digestible ingredients and formulated on the basis of digestible amino acids have been demonstrated in several recent reports. These findings have led to growing interest in the use digestible amino acid values as the basis of poultry feed formulations. It is also increasingly accepted that the determination of amino acid digestibility in poultry should be based on the analysis of ileal digesta. However, currently there is no universally accepted method for the measurement of apparent ileal amino acid digestibility and a number of variations exist, including differences in: (i) assay diets, (ii) indigestible marker used, (iii) age of birds (iv) method of euthanasia of birds, (v) method of digesta collection, (vi) site of digesta collection and (vii) processing of ileal digesta. The aim of this presentation is to highlight the need for a consensus method to determine ileal amino acid digestibility for poultry, especially given the recent interest worldwide to expand the ileal digestibility database for locally available ingredients. This will be necessary to provide a clear guideline on digestibility measurement for researchers and students starting research in this area and also will enable direct comparison of results of studies from different laboratories.

It is also recognised that apparent ileal amino acid digestibility values of individual ingredients may not be additive when ingredients with low amino acid digestibility and/or anti-nutritive factors are used in feed formulations. This limitation could be overcome by standardising these estimates through corrections for basal endogenous losses, which are defined as the minimal loss of endogenous amino acids. The basal endogenous losses are proportional to dry matter intake and independent of the composition of the ingredient or diet. The major challenge is how to measure these basal endogenous losses. Interestingly, for the pig industry, a recent recommendation suggests that basal ileal endogenous losses of amino acids should be measured in assays using a defined protein-free diet. In poultry, only limited published data is available on the ileal endogenous amino acid losses at the distal Ileum in broilers. Thus the secondary aim of this presentation is to promote discussion among researchers on what constitutes basal endogenous losses and to agree on the best approach that can be used universally in the calculation of standardised ileal digestibility values for poultry. Failure to agree on a universal approach will only lead to further confusion among the end-users, the commercial nutritionists.