EFFECT OF HEAT-STRESS AND DRINKING-WATER SALT SUPPLEMENTS ON PLASMA ELECTROLYTES AND ALDOSTERONE CONCENTRATION IN BROILER-CHICKENS

An experiment was conducted to evaluate the effects of supplementing d rinking water with isomolar (0.067 mol/l) KCl or NaCl on mass gain, fo od and water consumption, rectal temperature, and plasma concentration s of aldosterone, Na+, and K+ in broiler chickens reared in thermoneut ral and cycling heat stressing environments. Heat stress decreased (P less than or equal to 0.05) mass gain, food consumption, and plasma co ncentrations of Na+ and K+, while increases (P less than or equal to 0 .05) in plasma concentrations of aldosterone, rectal temperature, and water consumption were observed. Drinking water supplemented with eith er KCl or NaCl increased (P less than or equal to 0.05) broiler mass g ain and water consumption, but had no effect (P>0.1) on the other vari ables evaluated. The results of this study indicate that broiler chick ens in a heat stress environment are under osmotic stress and suppleme nting drinking water with 0.067 mol/l KCl or NaCl does not lessen this stress.