Skip to main content
SLU publication database (SLUpub)

Research article2006Peer reviewed

Prediction of energy and protein digestibility in pig feeds using growing rats as a model

Jorgensen H, Lindberg JE


The present investigation was undertaken firstly to establish the relationship between coefficient of total tract digestibility of energy (CTTAD-E), and dry matter (CTrAD-DM) and organic matter (CTTAD-OM) in a wide range of feedstuffs using growing rats. Secondly to establish prediction equations on CTTAD-E and crude protein digestibility (CTTAD-CP) in growing pigs from digestibility estimated with growing rats. Further the established equations were evaluated with independent set of data. In the first part of the study 18 experimental diets varying widely in chemical composition was used together with 164 diets each prepared with a different feedstuff and adjusted to 15 g N per kg DM with a N-free mixture. In the second part of the study a total of 138 diets was used of which 56 were classified as cereal and cereal by-products as main ingredients. Further for evaluation of the equations 13 diets composed of hulled or naked barley and oats was prepared. All diets were assayed in digestibility experiments. Each diet was assayed with either three to five growing pigs in balance periods of 12 days with a 7 days collection period or five growing Wistar rats in balance periods of 9 days with 5 days collection. A close relationship was found between CTTAD-DM/CTTAD-0M and CTTAD-E. When diets contain a high content of ash it is preferred to use CTTAD-OM to predict CTTAD-E. The relation between the growing pig and the growing rat for CTAD-E for all 138 diets showed a coefficient of variation (CV) of 4.7. When a sub-sample (n = 56) of cereal and cereal by-products was used the CV was more than halved to 2.2. Pigs digested most fibrous diet to a higher degree than rats causing the higher CV. The correlation of CTTAD-CP between the two species was lower than for CTTAD-E. The derived prediction equations were tested with an independent set of data. In conclusion, the results showed the potential of using the rat model as a tool in feed evaluation for pigs. However, for practical purposes the equations could be used to predict the energy value with an acceptable precision. (c) 2005 Elsevier B.V. All rights reserved

Published in

Animal Feed Science and Technology
2006, Volume: 127, number: 1-2, pages: 55-71

    UKÄ Subject classification

    Veterinary Science
    Animal and Dairy Science

    Publication identifier


    Permanent link to this page (URI)