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