Heat stress has a significant impact on broiler production and is an increasing challenge for breeders. We investigated the comparison of production results between National Research Council (NRC) recommendations (KONT1) and the Aviagen breeding house recommendations for broiler Ross 308 (KONT2) in a nutritional experiment. Both recommendations are designed for raising chickens in thermoneutral conditions, but we wanted to investigate whether the recommendations are suitable for raising animals exposed to heat stress. We also investigated the effect of individual feed supplements in supplementation to the Aviagen recommendations (KONT2): vitamin E (KONT2+E), vitamin C (KONT2+C), selenium (KONT2+S) and their combination (KONT2+ECS), on the oxidative status of broilers. The study included 120-day-old chickens randomly divided into 6 groups for each treatment. We monitored mortality and production outcomes (weight, growth, feed intake and feed conversion rate). At slaughter, the individual parts of the carcass and the organs were weighted and the percentages calculated. In addition, blood was taken from the chickens for measurements of oxidative status parameters in the blood. Our results show that the NRC dietary guidelines are generally not sufficient to meet antioxidant requirements during heat stress. Therefore, supplementation with antioxidants seems advisable under both normal and stressful conditions. The Aviagen guidelines generally cover the needs under rearing conditions without heat stress. Although we could not confirm a synergistic effect of combined supplementation of vitamins E, C and selenium, a trend was observed. Further studies are needed to determine the optimal amounts of each supplement or their combinations under stressful rearing conditions.
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