The Synergistic Effect of Vitamin C Supplementation and Early Feed Withdrawal on Heat Stress Mitigation in Broiler Chickens.

Mitigating stress responses is crucial for maintaining optimal productivity and profitability in modern poultry production. The effects of early feed withdrawal (EFW) and vitamin C (Vit C) supplementation, both individually and in combination, on heat-stressed broilers' productivity, stress responses, and metabolic markers were investigated. In total, 240 newly hatched Cobb-500 male chicks were randomly distributed to four treatment groups (six replicates × 10 birds per group). A basal diet was offered to the control group; meanwhile, the EFW group underwent a 24 h early feed withdrawal on day four of age. The Vit C group was given 200 mg/kg vitamin C daily, and the EFW + Vit C group received both interventions. The study was executed under hot summer conditions, where the average minimum and maximum temperature-humidity Index (THI) were 29.15 ± 0.78 and 33.34 ± 0.76, respectively. The results demonstrated a superior stress-mitigating effect when EFW was combined with Vit C supplementation, leading to a significant improvement in productive parameters and elevated blood metabolic hormone levels. Additionally, total antioxidant capacity was enhanced, hepatic endogenous antioxidant enzyme expression was upregulated, and stress biomarkers were reduced. Furthermore, the economic efficiency indicators were significantly improved with EFW, and when EFW was combined with Vit C addition. These findings suggest that integrating multiple stress mitigation strategies, such as EFW and Vit C supplementation, may be more effective in relieving the adverse effects of heat stress by restoring homeostasis and optimizing broilers' productivity and profitability.