SELF-SELECTION OF DIETARY-PROTEIN AND ENERGY BY BROILERS GROWN UNDER A TROPICAL CLIMATE - ADAPTATION WHEN EXPOSED TO CHOICE FEEDING AT DIFFERENT AGES

Three hundred broiler chicks (Hubbard) of both sexes were assigned to five feeding treatments: TO received a complete diet (control), TI was a choice feeding system with simultaneous access to an energy-rich fe ed (ground corn) and a protein concentrate (43.7% CP), and T2, T3, and T4 were introduced to choice feeding after 1, 3, and 5 wk, respective ly, of consuming the complete diet. At 1-d-old, TI chicks showed a mar ked preference for corn, with only 21.4% of their intake being the pro tein concentrate diet. Intake of the concentrate progressively increas ed to 40 to 45% after 3 d of adaptation, resulting in diets with 22.5 to 24.3% CP. When broilers fed the complete diet for 1 to 5 wk (T2, T3 , T4) were changed to choice feeding, on the Ist d, their feed choice intake was similar to that of T1 chicks at the same age. Visual observ ation and tactile assessment of the feed particles during the initial period allowed the chicks to quickly evaluate the new feeds and to ada pt their feeding behavior. Although total feed intake to 6 wk of age w as not significantly affected by the feeding treatments, broilers on c hoice feeding selected diets with a lower percentage of CP and had low er live body weights at 6 wk than those fed the complete diet (TO).