As antioxidants such as some functional oils are good candidates to mitigate heat stress, a commercial blend of functional oils (Essential, Oligo Basics USA LLC, Cary, NC; active ingredients: cashew nut shell oil and castor oil) was used to study the effects of two ambient temperatures (moderate and high) on broiler chicken performance and carcass parameters. A total of 2,240 straight-run one-day-old chickens were sorted by weight, randomized among 28 floor pens with 80 chickens per pen and 7 replicates for each treatment. Birds were assigned to one of 4 dietary treatments in a 2 × 2 factorial arrangement with two temperature environments (moderate and high) and without or with Essential supplementation (1.5 kg/ton). Variances for the average temperature, relative humidity, and dew point for the two environments were different (P < 0.001), showing that the high-temperature environment reached higher temperatures and dew points. Essential supplementation increased body weight gain at 42 D of age (2.548 vs. 2.508 kg; P < 0.01) and tended to improve feed conversion (1.621 vs. 1.644; P = 0.09) independent of temperature environment. The high-temperature environment increased mortality (7.5 vs. 12.4%; P = 0.03) and carcass yields (77.5 vs. 76.2%; P < 0.01). Breast yields were affected by an environment by Essential interaction (P < 0.01). Whereas the high-temperature environment decreased breast yield in control birds, it did not decrease breast yield in birds supplemented with Essential. Finally, breast yields were increased by Essential supplementation (23.6 vs. 22.9%; P < 0.01) regardless of the ambient temperature. In conclusion, Essential supplementation improved weight gains and carcass characteristics, and high-temperature environments decreased breast yields when Essential was not supplemented.
Keywords: carcass; functional oils; heat stress.
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