Prediction of the performance of broiler chicks from apparent metabolizable energy and protein digestibility values obtained using a broiler chick bioassay

Samples of wheat (54) and barley (87) were included in a series of broiler chick bioassays. For each cereal, fed at 80% of a basal diet with or without enzyme, apparent metabolizable energy (AME), retained nitrogen, digesta viscosity, excreta dry matter (DM), and broiler performance (feed intake, body weight [BW] gain, and feed conversion) were measured. Correlation coefficients were calculated between the predictor and the performance variables, separated according to whether or not the diets included feed enzymes. Some correlations between measures of AME and BW, feed efficiency, and to a lesser degree feed intake were significant, but none were high. The correlation coefficients were higher when feeds were not supplemented with an enzyme because enzyme supplementation reduced the variation in both AME and performance by reducing the antinutritive effects of non-starch polysaccharides (NSP). including a measure of voluntary intake in AME (AME level multiplied by feed intake) resulted in higher correlations with performance. Evaluation of the feeding value of wheat and barley by researchers or the feed industry will require the determination of available energy and the NSP contents.