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ABSTRACT: 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.

ABSTRACT: This study evaluated the effects of vitamin E (Vit E) and selenium (Se) supplementation on mRNA abundance of antioxidant, immune response, and tight junction genes, as well as taxonomic and functional profiles of ileal microbiota of broilers exposed to daily 4-h elevated temperature during d 28 to 35. A total of 640-day-old Cobb male broiler chicks 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). Vit E and organic Se were added to the basal diet at the rate of 250 mg/kg and 1 mg/kg, respectively. Liver and jejunum tissue samples were taken on d 27 (1 bird/pen), d 28 and d 35 (2 birds/pen) from birds for qPCR analysis. Data were subjected to a 2-way ANOVA using the GLM procedure of JMP. Ileal contents were taken on d 27 and d 35 for microbial profiling. Microbiota data were analyzed in QIIME 2 and significance between treatments identified linear discriminant analysis effect size (LEfSe, P < 0.05). Dietary Vit E/Se significantly downregulated the mRNA levels of HSPs in liver and jejunal tissues of the HS-challenged birds both on d 28 and d 35. Moreover, mRNA abundance of TLR2, TNFα, IFNγ, IL-1β, IL-10, and iNOS in the liver were significantly downregulated in birds fed the Vit E/Se diet on d 35. However, dietary treatment had no significant impact on oxidative stress, immunity, and gut integrity related genes analyzed in jejunal tissues on d 28 and d 35, except downregulation of IFNγ on d 35 (P = 0.052). LEfSe analysis revealed that Lachnospiraceae FE2018 and Ruminococcaceae NK4A214 groups was enriched in the Vit E/Se birds on d 35. Moreover, PICRUSt analysis predicted significant functional differences among the treatment groups. In conclusion, dietary supplementation of Vit E/Se mitigated the negative effects of HS potentially via improving antioxidant status, regulating cytokine responses and modifying ileal microbiota and its function.