EFFECT OF ACID OR ALUMINUM ON GROWTH AND ADRENAL-FUNCTION IN YOUNG CHICKENS

Acid precipitation can have a harmful effect on aquatic birds, due in part to increases in aluminum availability. Young rapidly growing (bro iler strain) chickens were used as a model to examine the effects of a luminum and acid on growth and circulating concentrations of adrenocor ticol hormones. Two concentrations of acid (sulfuric acid) or aluminum (aluminum sulfate) or sodium sulfate were administered to a heavy (br oiler) strain of chickens for 10 days (Days 4 to 14 of age). Additiona l treatment groups included a control diet either fed ad libitum or pa ir-fed relative to the chicks an the acid or aluminum diets. Compared with the chicks receiving the control diet ad libitum, growth (body we ight) was reduced in chicks on the aluminum (high and low level), acid (high level), and sodium sulfate (high level) treatments and the resp ective pair-fed groups. Circulating concentrations of corticosterone ( B) were elevated in the chicks receiving the high dose of aluminum and the respective pair-fed control when compared with the chicks which h ad free access to the control diet. Thus, the increase in plasma B app ears to be linked to the low food intake and nor to the Al per se. Cir culating concentrations of aldosterone were increased in the chicks re ceiving either the high dose of aluminum or the acid relative to chick s fed the control diet (both an libitum or pair-fed controls), However , circulating concentrations of aldosterone were unaffected by either dose of sodium sulfate employed. Thus, the increase in plasma aldoster one appears to be specific to the metabolic acidosis created by Al or acid. It is concluded that environmental acid may either directly or i ndirectly influence adrenocortical function. Moreover, the present stu dy provides evidence for the independent control of circulating concen trations of corticosterone and aldosterone in the chicken. (C) 1996 Ac ademic Press, Inc.