Why does an optimal dietary electrolyte balance (dEB) prevent heat distress and maintain eggshell thickness in brown layers during peak summer?

During peak summer in Pakistan, when ambient temperatures in areas like Multan, Faisalabad, and Sukkur soar past 40°C, laying hens suffer from severe heat distress. To cool themselves, hens pant, which causes excessive loss of carbon dioxide ($CO_2$) through their lungs. This respiratory hyperventilation shifts their blood pH from neutral to alkaline, a condition known as respiratory alkalosis. To compensate, the kidneys rapidly excrete bicarbonate ($HCO_3^-$) ions, leading to a critical shortage of the bicarbonate needed in the shell gland to form calcium carbonate ($CaCO_3$). This results in extremely thin, fragile eggshells. By adjusting the dietary electrolyte balance (dEB, calculated as $Na^+ + K^+ - Cl^-$) to an optimal range of 220–250 mEq/kg using sodium bicarbonate ($NaHCO_3$) or potassium chloride ($KCl$), nutritionists can restore blood acid-base homeostasis. This prevents systemic acidosis, maintains blood calcium transport, and ensures high shell thickness even under extreme thermal stress. Farmers can study advanced avian physiology in the Poultry Encyclopedia, purchase premium electrolyte stabilizers on Poultry Plaza, monitor raw feed ingredient prices on Poultry Rates, and list high-grade brown eggs on Murghi Mandi.