Methodological considerations for the determination of standardised ileal digestibilities of amino acids in newly weaned pigs

Publication Type

Contribution to conference

Authors

Eklund M., Piepho H.P., Rademacher M., Mosenthin R.

Year of publication

2007

Published in

EAAP Publication

Editor

European Association for Animal Production

Pubisher

Wageningen Academic Publishers , Wageningen, Niederlande

Band/Volume

124/

Series/labeling

EAAP-Publication

ISBN / ISSN / eISSN

978-90-8686-041-8

Page (from - to)

421-422

Conference name

Energy and Protein Metabolism and Nutrition

Conference location

Vichy, France

Conference date

09.09.2007

Keywords

Aminosäure, digestibility, ileal amino acid, weaning pig

Introduction:
Standardised ileal digestibilities (SID) of crude protein (CP) and amino acids (AA) have been introduced into diet formulation for pigs but barely any reports exist on the measurement of SID in newly weaned pigs. Either regression analysis techniques or correction of apparent ileal digestibilities (AID) for basal ileal endogenous CP and AA losses (IAALB) may be used to obtain SID values. Moreover, different methods, including, regression analyses or feeding protein sources with assumed CP and AA digestibilities of 100%, such as casein, can be used to obtain estimates of IAALB. In newly weaned pigs, however, a limited capacity for CP digestion and AA absorption may affect the determination of SID and IAALB. Therefore, the aims of the present study were to estimate IAALB and SID in newly weaned pigs, which were fed graded levels of CP originating from casein.
Material and methods:
Fourteen 3-wk old barrows (12+2 for replacement; German Landrace x Piétrain) were surgically fitted with simple T-cannulas at the distal Ileum. The piglets were randomly assigned to 6 semi-synthetic cornstarch-based diets (including 10% dextrose, 7% cellulose, 2% soybean oil, 4% mineral and vitamin premix, 0.1% titanium dioxide) with graded inclusion levels of casein, crystalline threonine and cystine, which were added to the diets at the expense of cornstarch (9.0, 15.5, 22.0, 28.5, 35.0, 41.5% CP, as-fed basis). Four weekly repeated measurements of AID of CP and AA were conducted (n=2 piglets, resulting in 8 observations per CP level). Starting with 28 d of age, the diets were fed at a level of 3% of individual body weight, which was determined weekly to keep the feed intake in relation to body weight at a constant level for all animals throughout all 4 experimental periods. To estimate SID (%) in casein, the following methods were used: (i) Ileal recoveries of CP and AA (%) originating from casein were estimated by linear regression analysis between total ileal recoveries and dietary intakes of CP and AA (g/kg DMI); (ii) The SID of CP and AA (%) originating from casein were estimated by linear regression analysis between apparent ileal digestible and total dietary contents of CP and AA (g/kg DMI); (iii) The AID of CP and AA (%) were corrected for IAALB (g/kg DMI). To estimate IAALB (g/kg DMI) the following methods were used: (i) Extrapolation from linear regression analysis between apparent ileal digestible and total dietary contents of CP and AA (g/kg DMI); (ii) Ileal recoveries from piglets fed casein were considered to represent IAALB (g/kg DMI) and were expressed as a function of the dietary CP level (% DM). The data were subjected to mixed model analysis using the MIXED procedure of SAS. The errors of repeated measurements on the same subject (animal within CP level) were assumed to be serially correlated and different correlation structures were fitted.