Mixture experiments: a severe test of the ability of a broiler chicken to make the right choice

1. A mixture experiment was used to measure the biological performance (wei ght gain and food conversion efficiency) of broilers from 7 to 21 d of age when Fed 1 of 13 combinations of 3 protein sources. The objective was to de termine the combination of ingredients that would maximise biological perfo rmance. 2. The experiment consisted of 2 diet series: in the 1st series, the 3 prot ein sources used were fishmeal, sunflower oilcake meal and soyabean oilcake meal, and in the 2nd, the soyabean oilcake meal was supplemented with DL-m ethionine. The combinations of 2 and 3-component mixtures that maximised pe rformance in the 2 series were then compared with the selections made by ch ickens offered a choice of 2 or 3 components separately. 3. In all cases, the choices made by the broilers coincided with those mixt ures that maximised performance. 4. It is clear from this experiment that broiler chickens will attempt to m aximise performance by choosing the best possible combination of protein so urces when given the opportunity to do so.