Effect of energy/protein ratio on productive performance and carcass composition of male broilers

To minimize excessive carcass fatness of broiler chicken, a diet with a low energy/protein ratio (EPR 117 resulting from 2800 Kcal ME/kg and 24% crude protein) was fed between days 7-14 (E1), 7-21 (E2) or 21-35 (E3); the rest of the time, up to 49 days of age, the chicks were fed as the control group, with EPR's of 138, 162 and 181 according to age. The results indicate that the feeding of a ration with a low EPR at different ages did not importantly impair productive performance although treatments E2 and E3 produced lower live weights and a decreased feed conversion (P less than or equal to 0.03). Concerning carcass characteristics, there was a trend to lower abdominal fat content in all experimental groups as compared to the control group and a lower ether extract content in the edible part of broilers from treatments E2 and E3 (P less than or equal to 0.06). More research is needed to find a metabolic explanation for these feeding effects.