Nutritional Strategies for Mitigating Heat Stress in Broilers: A Review of Acid-base Balance and Osmoregulation

Abstract

This review focused on the mechanisms of action and effects of these dietary additives in maintaining acid-base balance and osmoregulation under heat stress conditions. Heat stress, a major challenge affecting poultry production, particularly in tropical and subtropical regions. It disrupted acid-base balance, reduced feed intake, impaired growth performance, and increased mortality in broilers. Nutritional interventions such as ammonium chloride, sodium bicarbonate, betaine, and vitamin C have shown significant potential in alleviating heat stress by improving physiological and metabolic responses. The findings suggested that strategic supplementation of these additives could enhance performance, improve immunity, and support overall broiler health. Furthermore, heat stress was associated with oxidative stress and electrolyte imbalance, which adversely affected cellular integrity and metabolic efficiency in broilers. Ammonium chloride and sodium bicarbonate were reported to play a significant role in regulating systemic pH and maintaining electrolyte balance, thereby supporting physiological stability during thermal stress. Betaine acted as an osmo-protectant and methyl donor, contributing to improved cellular hydration, nutrient utilization, and intestinal health. Vitamin C functioned as a potent antioxidant that helped reduce oxidative damage and enhanced immune response under stress conditions. Overall, the reviewed literature indicated that the inclusion of these dietary additives, either individually or in combination, improved feed efficiency, growth performance, and survivability of broilers. These findings highlighted the importance of adopting appropriate nutritional strategies to mitigate heat stress and sustain productivity in poultry production systems.