Influence of dietary vitamin E and selenium supplementation on broilers subjected to heat stress, Part I: Growth performance, body composition and intestinal nutrient transporters.

High ambient temperature is one of the most common stressors in modern poultry production, resulting in reduced feed intake, weight gain, and increased mortality. This study evaluated the effects of vitamin E (Vit E) and organic selenium (Se) supplementation on performance, body composition, core body temperatures, and mRNA abundance of nutrient transporters in the jejunum of broilers exposed to daily 4-h elevated temperature during d 28 to 35. A total of 640 Cobb male birds were randomly allocated to 32 floor pens in a 2 × 2 factorial arrangement that included ambient temperature (thermoneutral, [TN]; or heat stress, [HS]) and dietary treatments (basal diet or Vit E + Se). Four rooms were used (2 TN and 2 HS) each housing half of the 8 replicate pens per group. Vit E and organic Se were added to the basal diet at the rate of 250 mg/kg and 1 mg/kg diet, respectively. Data were subjected to a 2-way ANOVA using the GLM procedure of JMP (SAS). During the HS period, birds fed the Vit E/Se diet had significantly lower mortality compared to nonsupplemented group (1.92% vs. 7.01%). Moreover, dietary Vit E/Se supplementation had a significant effect on performance by increasing BWG, FI, and European production efficiency factor (EPEF) during the entire experimental period (d 0-35). Dietary Vit E and Se supplementation significantly increased carcass, tissue, lean, and fat weights as well as bone mineral content (BMC) and bone mineral density (BMD) on d 35. Birds fed Vit E/Se supplemented diet had significantly lower (P = 0.010) core body temperature compared to birds fed the basal diet on d 30. Dietary treatment did not influence mRNA abundance of PepT1, SGLT1, or NaPi-IIb on d 28 or d 35. However, HS significantly upregulated levels of PepT1 and NaPi-IIb (P < 0.001) and downregulated that of SGLT1 (P = 0.017) on d 28. In conclusion, dietary Vit E and Se supplementation significantly improved broiler growth performance and carcass composition, and reduced heat-related mortality and core body temperature (on d 30) without influencing the mRNA abundance of intestinal nutrient transporters.