RESUMO
In order to study the influence of lecithin and vegetable oils on improving productive and reproductive performance, egg quality, and metabolic profile of dual-purpose crossbred hens in the tropics, a total of 224 hens, 47-wk old, 112 each of Gimmizah and Silver Montazah strains were fed seven isonitrogenous diets. Experimental treatments consisted of feeding seven different diets to layers; four isocaloric diets containing either no added lipid (control), 3% vegetable oil mixture, 3% soy lecithin or 6% soy lecithin; and three high-energy level diets, containing an extra 3% vegetable oil mixture, 3% or 6% soy lecithin added to the control diet. Thus, the experimental design was factorial, consisting of seven lipid treatments by two strains of hens. Results indicate that 3% lecithin as an extra ME source, or feeding 11.72 MJ ME/kg diet containing the same level of lecithin, improved productive and reproductive performance of crossbred hens. Moreover, lecithin at 6% as an extra ME supplement significantly increased yolk percentage and improved Haugh unit score and yolk color, while increasing EE digestibility and plasma total lipids. Hen strain had a significant effect only on digestibility of OM, percentage liver and Haugh unit score, with the Gimmizah strain having higher values.