The influence of dietary ox idized oil was studied on laying hen performance, egg quality and blood metabolites. Experiment was conducted on 160 laying hens (Hy - Line W - 36, 54 - 61 wk of age) in a completely randomized design with five treatments and four replicated cages containing ei ght birds per cage . Dietary treatments replaced fresh soybean oil in the control diet (3% fresh soybean oil, 15.25% crude protein, and 2858 Kcal/kg metabolizable energy) with 0, 25, 50, 75 and 100% oxidized oil. Egg production and egg weight were recorded daily and feed intake, feed conversion ratio, and egg mass were calculated weekly. Egg quality traits were recorded on a biweekly basis. Hen’s body weight was measured individually at the beginning and end of the experiment. Serum metabolites were determin ed at the end of the experiment. There was a significant difference between diets with different oxidized oil levels in egg weight , egg mass , Egg production , and feed conversion ratio ( P < 0.05). Feed intake was not affected by dietary treatments. There wa s no significant difference between oxidized oil levels on blood serum triglyceride, total cholesterol, high - density lipoprotein, low - density lipoprotein and very low - density lipoprotein . Malondialdehyde of the liver was not affected by oxidized oils. The results of this study have clearly demonstrated that maximum 25% oxidized oil could be replaced by fresh oil in the diets without any adverse effect on the performance of laying hens.
