The objective of this study was to examine the impact of adding an emulsifier, de-oiled soybean lecithin (DOL) in diet,
on growth performance, blood parameters, antioxidant potential, thyroid hormones (T3 & T4), and serum immunoglobulins
in two distinct strains of commercially raised broilers, Ross 308 (S1) and Evian 48 (S2). A total of 800 oneday-
old broiler chicks from both strains (N = 400 each) were assigned to a control group (T0) and three dietary
treatments, each with five replicates of 20 birds. Experimental treatments included a basal diet supplemented with
varying levels of de-oiled lecithin (DOL): T1 =0.5 g/kg, T2 =1 g/kg, and T3 =1.5 g/kg. The study used a 2 ×4 factorial
design, which allows for the examination of the effects of two factors (in this case, strains and dietary treatments) on the
outcome variables. Following 35 days, the broilers of strain S1 and those fed the T3 supplemented diet exhibited
superior body weight (BW), body weight gain (BWG), cumulative feed intake (CFI), cumulative feed conversion ratio
(CFCR), performance index (PI%), and lower mortality rate (Mr %) (P