The Use of Dietary Minerals During Heat Stress in Broilers

Abstract Mineral supplementation has been conclusively demonstrated to decrease mortality and improve growth of broilers during heat stress. The most effective supplement appears to be NaHCO 3 , which, although it has no favorable effect on pH, relieves the bicarbonate (HCO 3 − ) deficiency brought about by a developing respiratory alkalosis. Blood pH may be reduced with NH 4 Cl supplements but its potency as an acid leaves a much narrower margin for error. At the present time dietary electrolyte balance [(DEB; (Na + ) + (K + ) − (Cl − )] appears to be inappropriate for predicting the growth of heat-stressed broilers. The dietary arginine:lysine ratio has been found to be important during heat stress but is also influenced by dietary NaCl levels. Practical mineral supplementation during heat stress requires close attention to all dietary minerals and amino acid balance.