Heat stress relief for broiler chickens: organic selenium and a vitamin C and E blend can enhance growth, nutrient digestibility, and blood parameters

This study aimed to evaluate the effects of dietary supplementation with organic selenium (OR-Se) and/or vitamins C and E on the rectal temperature (Rectal-T), growth performance, carcase yield, intestinal morphology, plasma thyroid hormone levels, and antioxidant status of broilers reared in hot environmental conditions.Under heat stress conditions (29.4 to 33.6 � C), 360 Arbour Acres chicks were fed in a (2 � 3) factorial design with two dietary levels of organic selenium (0 and 0.6 mg/kg) and three dietary levels of a mix of vitamins C and E (0, 200 and 250 mg/kg).Chicks were randomly assigned to six treatments (T) with three replicates of 20 birds each: the 1st group (T1): basal diet with no supplementation (control group); the 2nd group (T2): basal diet supplemented with 0.6 mg OR-Se/kg; the 3rd group (T3): basal diet with a mixture of vitamins C and E, 200 mg of each/kg diet (Vita-Mix A); the 4th group (T4): basal diet with a mixture of vitamins C and E, 250 mg of each/kg diet (Vita-Mix B); the 5th group (T5): basal diet with (Vita-Mix A) 0.6 mg OR-Se/kg diet; the 6th group (T6): basal diet with Vita-Mix B and 0.6 mg OR-Se/kg diet for a five-week feeding period.Results showed that chicks fed diets supplemented with OR-Se and/or vitamins (C, E) had lower (p < 0.01) rectal-T, growth performance indicators (except feed intake).Also, compared to un-supplemented birds, the carcase yield, digestibility of ether extract, and antioxidant indices were significantly improved.In conclusion, dietary 0.6 mg OR-Se/kg and/or a mixture of vitamins C and E (both at 200 or 250 mg/ kg) improved growth performance, carcase yield, nutrient digestibility, and antioxidant capacity under heat-stress conditions.In addition to the previously mentioned results, it would be more reliable when applied to a large number of chicks to ensure data robustness and reliability for productive performance indices.HIGHLIGHTS � Adding 0.06 mg of organic selenium plus a mixture of vitamins C and E to the broiler's diet (per 1 kg diet) improved growth performance.� Including 0.6 mg of organic selenium plus a mixture of vitamins C and E (per 1 kg diet) in the broiler led to a better average feed conversion ratio throughout the rearing period and boosted the FCR of broiler chicks.� Vita-Mix plus organic selenium supplementation led to better antioxidant status (GSH-px, SOD, and MDA) of broiler chicks.