Methionine Requirements of Chickens with Various Body Weights

Abstract

Methionine requirements of male White Leghorn chickens were estimated at 5 stages of growth by growth and the recovery of ¹⁴C in respiratory carbon dioxide. The methionine requirement for maximum daily gain decreased with increasing age according to the equation; log Y=−0.000243 ×− 3.22, where Y and X represent the methionine requirement as percentage of the diet and g of average body weight of the chickens during the experimental periods that achieved maximum daily gain. The recovery percentage of ¹⁴C derived from methionine-1-¹⁴C remained low, and then increased rapidly. The methionine requirement found from the recovery of ¹⁴C also decreased with increasing dietary methionine levels according to the equation; log Y=−0.000216 ×− 3.02, where Y and X represent the methionine requirement as percentages of the diet and g of body weights of chickens at the beginning of the recovery test for ¹⁴C. Dietary cystine spared the methionine requirement for growth, but did not affect the recovery of ¹⁴C in the respiratory carbon dioxide.