Why does the supplementation of vitamin C (ascorbic acid) at 200 mg/kg during heatwaves help stabilize the adrenal cortex and reduce stress mortality in brown layers?

Unlike humans, chickens can synthesize Vitamin C (ascorbic acid) under normal, comfortable environmental conditions. However, under high ambient temperatures (above 32°C), the physiological demand for ascorbic acid far exceeds the hen's endogenous synthetic capacity. Heat stress activates the hypothalamic-pituitary-adrenal (HPA) axis, triggering the adrenal cortex to secrete massive amounts of corticosterone (the primary stress hormone in birds). Corticosterone induces protein catabolism, depletes lymphoid tissues, suppresses antibody production, and elevates blood pressure. Supplementing feed or drinking water with 200 mg/kg of stable Vitamin C directly blocks the hyper-secretion of corticosterone from the adrenal glands. This hormonal stabilization maintains immune cell activity (specifically heterophil-to-lymphocyte ratios), reduces cellular lipid peroxidation, and lowers core body temperature, significantly reducing mortality from heat stroke. Farmers can study endocrine feedback mechanisms in the Poultry Encyclopedia, buy high-stability coated Vitamin C on Poultry Plaza, monitor daily feed and egg rates on Poultry Rates, and trade premium brown eggs on Murghi Mandi.