Extract viscosity as a predictor of the nutritive quality of wheat in poultry

The nutritive value of wheat varies greatly in poultry, especially in young broilers, due to low apparent metabolisable energy (AM E) contents of some wheats (Rogel et al. 1987). The low-ME wheat phenomenon has three major economic implications: (1) increased feed cost due to poor feed efficiency; (2) elevated litter problems due to watery and sticky excreta; and (3) inaccuracy in least cost formulations. Rogel et al. (1987) examined the physical structure of the starch granule, grain hardness and the activity of trypsin inhibitors in low-ME wheats and excluded them as causative factors. Recently, Annison (1991) demonstrated that the soluble non-starch polysaccharides (NSP) in wheat are closely related to the AME values. Furthermore, supplementation of NSP degrading enzymes significantly improved the nutritive value of wheat in poultry (Annison 1992; Friesen et al. 1992). These results suggest that the NSP in wheat exhibit anti-nutritive activity and low-ME wheat phenomenon is a consequence of variation in the soluble NSP contents. The randomness of the problem demands a rapid assay for the prediction of the AME of wheats.