Effect of antioxidant inclusion and oil quality on broiler performance, meat quality, and lipid oxidation

The objective of the present study was to evaluate the effect of antioxidant inclusion and oil quality on broiler performance, meat quality, shelf life, and tissue oxidative status. Ross 308 male broilers were allotted to a randomized complete block design in a 2 x 2 factorial arrangement. Factors consisted of antioxidant (ethoxyquin and propyl gallate) inclusion at 2 levels (0 or 135 mg/kg) and oil quality (fresh soybean oil, control diet peroxide value <1 mEq/kg, or oxidized soybean oil, diet peroxide value 7 mEq/kg). Each treatment included 12 pen replicates comprising 24 birds for a total of 1,152 birds on trial allotted to 48 pens. On the final day of the study, 1 bird from each pen was killed by cervical dislocation and used for determination of tissue oxidative status. Another 5 broilers from each pen were processed at a commercial slaughtering facility. Immediately after processing, carcasses were transported to the University of Illinois Meat Science Laboratory (Urbana) for further analysis. With the exception of 2 responses (liver vitamin A and serum vitamin A), no interactions were found between antioxidant inclusion and oil quality. Body weight and weight gain were increased by dietary antioxidant inclusion (P < 0.001) and fresh oil (P < 0.001). Feed intake was increased in broilers fed the antioxidant (P = 0.047) and fresh oil (P = 0.062). Antioxidant inclusion had no effect on G:F (P = 0.18). Antioxidant supplementation had no effect on carcass weight (P = 0.202), dressing percentage (P = 0.906), breast yield (P = 0.708), or breast ultimate pH (P = 0.625) and had minimal effect on breast color. Antioxidant supplementation (P = 0.057) reduced breast thiobarbituric acid reactive substances after 7 d of display. Fresh oil decreased liver thiobarbituric acid reactive substances, whereas antioxidant inclusion increased serum and liver vitamin A and E concentration. The presence of an antioxidant in the feed protects lipids from further oxidizing, therefore increasing broiler performance and improving shelf life when using oxidized oil.