The study was based on correlating a dataset of in vivo mean starch digestibility coefficients obtained in the immediate post-weaning phase of piglets with a range of dietary in vitro variables. The paper presents a model that predicts (R2 0·71) in vivo average starch digestibility coefficients in the 0·5 small-intestinal region of newly weaned piglets fed cereal-based diets using seven in vitro variables describing starch properties that are fundamentally associated with the quality of feed materials, i.e. hydration, structure and amylolytic digestion. The variables were: Rapid Visco Analyser (RVA; measures the viscosity of materials when sheared under defined hydration and temperature regimens); RVA end viscosity; RVA (gelatinisation) peak viscosity; ΔH (gelatinisation enthalpy that provides an estimate of helical order or degree of crystallinity in starch); water solubility index (WSI; that denotes the amount of soluble polysaccharides released from starch granules to the aqueous phase); grain endogenous amylase (concentration of endogenous α-amylase in cereals, assessed by pasting cereal flours in 25 g of AgNO3, an amylase inhibitor v. water using RVA).
(Received August 13 2008)
(Revised November 02 2009)
(Accepted November 04 2009)
(Online publication December 21 2009)
p1 Present address: Council for Geoscience, 280 Pretoria Road, Private Bag X112, Pretoria 0001, South Africa
p2 Present address: School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Loughborough, Leicestershire LE12 5RD, UK
Abbreviations: G45, amount of glucose released at 45 min; G300, amount of glucose released at 300 min; PCA, principal components analysis; PLS, partial least squares; RVA, Rapid Visco Analyser; RVAc, RVA cold swelling viscosity; RVAe, RVA end viscosity; RVAp, RVA peak viscosity; WAI, water absorption index; WSI, water solubility index