Potassium Balance of the 5 to 8-Week-Old Broiler Exposed to Constant Heat or Cycling High Temperature Stress and the Effects of Supplemental Potassium Chloride on Body Weight Gain and Feed Efficiency

Four experiments were conducted to study the impact of ambient temperature and relative humidity stress upon K excretion and the effects of KCl supplementation of broilers exposed to chronic heat and cycling temperature stress. Potassium excretion, corrected for K intake and body weight, increased by 633% as ambient temperature was elevated from a constant 24 C to a constant 35 C. Feed (.73% K) and drinking water (0% K) were supplemented with KCl so effects of KCl on live weight gain and feed efficiency could be evaluated. In a previous study at thermoneutral temperature, no benefit of supplemental KCl was observed whereas in this study a dietary level of 1.5 to 2% K in the form of KCl improved gain under conditions of chronic high ambient temperature stress. This equals about 1.8 to 2.3 g K per chick daily or about .24 to .3% of the drinking water.