This trial was performed to determine the effect of rice bran oil (RBO) inclusion in diets of broiler chickens on performance, carcass characteristics, blood parameters, meat quality, antioxidant activity, liver lipid content, and liver histological structure. The 35-day feeding trial was conducted on 240 one-day-old Ross 308 broiler chickens, allocated to four treatment groups with six replicates each. RBO was examined at different inclusion levels, 0% (control), 1% (RBO1%), 1.5% (RBO1.5%), and 2% (RBO2%) in a completely randomized design. The results showed that at the end of the trial (35 days) the RBO supplementation had positive effects (p < 0.001) on the productivity parameters, but the feed intake was linearly decreased due to RBO inclusion. In addition, RBO supplementation linearly improved (p < 0.05) the dressing percentage, breast yield, immune organs relative weights, and meat glutathione concentration, while it decreased (p < 0.01) the abdominal fat yield and meat crude fat, triglycerides, cholesterol, and Malondialdehyde (MDA) contents in broiler's meat. Moreover, serum total protein, globulin, and high-density lipoprotein contents improved noticeably (p < 0.01) due to offering an RBO-supplemented diet, but serum total lipids, total cholesterol, triglyceride, low-density lipoprotein, and aspartate aminotransferase concentrations linearly reduced (p < 0.01). The RBO supplementation augmented (p < 0.05) the phagocytic index, phagocytic activity, and antibody titer compared to control. On the other hand, RBO inclusion had no effect on the breast, thigh, or abdominal fat color parameters. Moreover, RBO supplementation reduced (p < 0.01) the content of total saturated FA (SFA), but increased (p < 0.01) the content of total monounsaturated FA (MUFA), and polyunsaturated FA in both breast and thigh meat. Chemical analysis of the liver tissue samples revealed that the inclusion of RBO linearly reduced (p < 0.05) hepatic cholesterol, triglyceride, and MDA contents. Histologically, the lipid percentage and number of lipid droplets (p < 0.01) were markedly lessened in the RBO-supplemented groups. The histological structure of the liver asses by light and electron microscope were normal in all groups without any pathological lesions. It is concluded that RBO could be used as a valuable ingredient in broiler chickens' diets to stimulate the growing performance and immune status, enhance the antioxidant activity and blood lipid profile, augment liver function, and improve the nutritive value of the meat.
Keywords: abdominal fat color; blood biochemical constituents; broilers; carcass traits; liver histology; meat fatty acid profile; performance.