Determining the optimum metabolizable energy of diets of ROSS 308 broiler chicks

In order to determine the most economic energy level of broiler diets, an experiment was conducted for 42 days using ROSS 308 broiler chicks. In a completely randomized design arrangement, 400 one-day old broiler chicks  were randomly distributed to 5 treatments and 4 replications. Each replication (one pen) contained 21 birds. Treatments were diets with 5 different metabolizable energy including 2900, 2950, 3000, 3050 and 3100 Kcal/Kg. The performance traits were measured periodically and at the end of the experiment.  Duncan’s mean comparison test showed that there was no significant difference between treatments in terms of weight gain during the starter period, but chicks fed by diets with 3100 Kcal/Kg showed significantly more weight gain than the other treatments in the growing (11- 24 d) and finishing periods (p < 0.05). Despite the feed consumption which were no significant difference between treatments in all of periods in the experiment, the feed conversion ratio of birds fed diets with 3100 Kcal/Kg was significantly less compared with the other treatments (p < 0.05). Results of carcass traits showed birds fed diets with 3100 Kcal/Kg had more breast efficiency than the other treatments.