The present experiment was performed to evaluate the effects of bovine bile and savory essential oil in saturated and/or unsaturated fats containing diets on performance, nutrient digestibility, blood parameters and antioxidants of broilers. In this experiment, we used, 480 day-old male broiler of Ross 308 commercial strain, in the form of 2 x 2 x 2 factorial split plots. The results showed that fat sources alone did not have significant effects on chicken performance (P>0.05). Yet, addition of cow bile and savory essential oil to fat containing diets improved feed conversion ratio and increased broiler productive index, by increasing the average daily weight with non-significant effect on daily feed intake (P<0.01). Similar results were observed in the interactions between fat sources, bile, and savory essential oil additives (P<0.05). Ileal nutrient digestibility was higher in canola oil containing diets than in beef tallow containing ones (P<0.01). The use of bile and savory essential oil additives in saturated and/or unsaturated fatty acid containing diets, increased the ileal digestion of nutrients, which was more prominent in beef tallow containing diets than in canola oil containing one. This resulted in interactions between fat sources and additives (P<0.01). The use of beef tallow compared to canola oil increased the blood triglyceride, total cholesterol, high-density lipo-protein (HDL) and very low-density lipoprotein (VLDL) levels in chickens (P<0.01). Regarding the antioxidant status of serum, the use of canola oil compared to beef tallow increased the serum level of superoxide dismutase enzyme (P<0.05). Bovine bile additive had no significant effects on the antioxidant status of fat containing diets (P>0.05). Interactions between fat source and type of additive showed that the use of both additives with fat sources improved the serum antioxidant indices of chickens (P<0.05). The general conclusion of the experiment is that in broiler chickens, the use of canola oil compared to beef tallow has positive effects on performance, nutrient digestibility, biochemical and blood immunity parameters, as well as serum antioxidant levels. Additionally, additives in fat containing diets, in particular savory essential oil, were effective on producing health friendly poultry.
