Ameliorative effects of dietary betaine hydrochloride on electrolyte stability and antioxidant capacity in heat-stressed arbor acre broilers

Abstract

Minimizing heat stress is essential to protect broiler performance, since high temperatures disrupt thermoregulation, redox balance, and nutrient utilization. This study was conducted to investigate betaine hydrochloride effects on thermoregulatory parameters, serum electrolyte and acid-base balance, antioxidant indices, and proinflammatory cytokine profile in heat-stressed Arbor Acre broilers. One hundred- and thirty-five-day-old broiler chicks were randomly assigned to three dietary treatments (0, 0.2, 0.4% Betaine HCl) using a completely randomized design. The treatments were made up of three replicates, with fifteen broiler chicks per replicate. The trial lasted 49 days. Temperature-humidity index (THI) was used in measuring ambient thermal condition. At day 49, blood samples were collected for electrolyte, antioxidant, and cytokine analyses. Dietary Betaine HCl did not significantly affect body temperature or respiratory rate (P>0.05). However, supplementation significantly influenced serum electrolyte regulation and antioxidant response. Birds receiving 0.2% Betaine HCl exhibited improved sodium concentration and higher blood pH (P<0.05), suggesting enhanced acid-base regulation under heat exposure. Glutathione concentration increased significantly (P<0.05) at 0.4% supplementation relative to the 0% group, showing enhanced endogenous antioxidant capacity. Malondialdehyde, interleukin-1β, and tumour necrosis factor were not significantly altered (P>0.05). These findings demonstrated that dietary Betaine HCl, particularly at 0.4%, enhanced antioxidant defence and contributed to maintaining electrolyte and acid-base stability in heat-stressed broilers without inducing inflammatory activation supporting betaine supplementation as a nutritional strategy for improving physiological adaptation to tropical heat stress.