Interrelationship between environmental temperature and dietary nonphytate phosphorus in chicks.
Four levels of nonphytate P (NPP; 0.2, 0.3, 0.4, and 0.5%; total P = 0.46, 0.56, 0.66, and 0.76%) and two temperatures (25 and 37 degrees C) were evaluated in chicks from 8 to 22 d. In experiment 1, crossbred male chicks (New Hampshire x Columbian) housed at 25 degrees C increased weight gain at all increasing NPP levels, but chicks exposed to 37 degrees C did not show increased weight gain beyond 0.3% NPP. In experiment 2, environmental temperature was not increased until d 15. Weight gain of crossbred male chicks fed the 0.2% NPP diet was similar at both temperatures, but chicks exposed to 37 degrees C had lower weight gains than chicks housed at 25 degrees C for all other NPP levels. On d 22 to 24, chicks that had been housed at 25 degrees C and fed 0.2, 0.3, and 0.5% NPP were moved to the 37 degrees C chamber to evaluate heat stress on older chicks. Chicks fed the 0.2% NPP diet showed 35% mortality within 6 h. In experiment 3, both male commercial (Ross x Ross) and crossbred chicks that had been housed at 25 degrees C and fed 0.2% NPP from 8 to 22 d showed increased signs of severe heat distress when exposed to 37 degrees C on d 22. Our results suggest that the NPP requirement for growth of 8-to-22-d-old chicks may be reduced by high temperature. However, a NPP deficiency may result in increased mortality or severe heat distress in older chicks that are exposed to an acute increase in temperature.
Department of Animal Sciences, University of Illinois, Urbana, Illinois 16801, USA.
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Persia
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Parsons
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Koelkebeck
D000375:Aging; D000818:Animals; D002645:Chickens / Q000254:growth & development*; D003433:Crosses, Genetic; D018882:Heat Stress Disorders / Q000401:mortality / Q000503:physiopathology / Q000662:veterinary; D006358:Hot Temperature; D008297:Male; D009751:Nutritional Requirements; D010758:Phosphorus / Q000172:deficiency; D016226:Phosphorus, Dietary / Q000008:administration & dosage*; D011201:Poultry Diseases / Q000401:mortality / Q000503:physiopathology; D015430:Weight Gain
D016226:Phosphorus, Dietary; D010758:Phosphorus