This work was done to investigate the effect of dietary emulsifier supplementation (Lipidol) in different life stages of broilers (Ross 308) with different soybean oil levels with or without a reduced energy diet (-50 Kcal/Kg) on growth performance, digestibility, serum lipid profiles, carcass traits, and some minerals deposition in the whole body and tibia of broilers during a 42-day rearing period. A total of 240 one-day-old chicks were randomly assigned to sixteen experiment groups, three replicates of five birds each. The birds with a 4 x 2 factorial design received either four levels of soybean oil (1, 1.5, 2, and 2.5% of diet) or two levels of energy [recommended energy (control) or reduced energy (RE)]. The results described that dietary addition of an emulsifier to the control group significantly increased (P < 0.05) body weight (BW), body weight gain (BWG), decreased feed intake, and improve feed conversion ratio (FCR) in all periods except BWG and FCR during the finisher period, which showed non-significant difference. Moreover, the deposition of calcium and phosphorus in the whole body and tibia in all periods was significantly increased. The addition of an emulsifier significantly increased the dressing percent (P < 0.05) and abdominal fat percent (P < 0.0001),whereas there was non-significant difference among all groups in dressing %, intestine, gizzard, liver, and abdominal fat % by interaction, and all carcass traits were not affected by different levels of oil. Low-density lipoprotein (LDL) - cholesterol and total cholesterol concentrations also were decreased (P < 0.05) by emulsifier supplementation during all periods. Meanwhile, increased triglyceride levels were detected during starter and finisher periods. Fat and dry matter digestibility was increased (P < 0.05) by emulsifier supplementation in the group fed the lowest oil level. In conclusion, growth performance, digestibility, cholesterol, and bone quality were improved by dietary lipidol supplementation to reduced energy diets to a level that reached the control.
