Fishmeal is the most interested animal protein source in poultry nutrition, mainly due to its highly qualified protein contents. This study was carried out to investigate the effects of formulating isonitrogenous and isoenergtic diets varying in fishmeal levels (0, 2.5 and 5% during starter and 0, 1.25 and 2.5% during grower period) on performance. A total of 264 Hubbard straight-run broiler chicks were allocated to three dietary treatments each replicated four times (22 chicks per pen) in a completely randomized design. Chicks body weights, daily gain, feed intake and feed conversion ratio were determined at 20 and 42 days of ages. The results showed that the body weight at 42d, daily gain during 0-42d and feed intake during 0-20d, 21-42d had significantly increased with fishmeal inclusion to the diets. In conclusion the results of this experiment indicated that the beneficial effects of fishmeal on broiler performances becomes most evident at higher level and last parts of growth periods, mainly via stimulation of feed intake.
