Methionine and protein requirements of turkeys 8 to 16 weeks of age

Turkeys of medium size strains were fed nine diets varying in protein and added methionine content from 8 to 12 and from 12 to 16 weeks of age. Four experiments with a 3 X 3 factorial design were conducted for each age period. Changing the protein content from 18 to 21% and from 21 to 24% during the 8- to 12-week period increased body weight gain by 11.2 and 5.1%, respectively. Changing the protein content from 15 to 18% and from 18 to 21% during the 12- to 16-week period increased body weight gains by 16.7 and 5.4%, respectively. Added methionine at the .2 and .4% levels increased body weight gains by 10.3 and 11.7% from 8 to 12 weeks and 3.5 to 2.3% from 12 to 16 weeks, respectively. The total sulfur amino acid requirements of Medium White turkeys during the 8- to 12- and 12- to 16-week periods were about .93 and .75%, respectively. Using data from the current and previous studies (Potter and Shelton, 1979), we calculated multiple regression analyses of percentage increase in body weight gains (Y1 of males or females during 2-week periods from increasing the dietary protein content by 3% on percent protein(X1) in the diet and average age (X2) of the turkeys. From these regressions, the protein requirement of Medium White turkeys is about 30.3% at one day of age and decreases .61 and .78 percentage units per week for males and females, respectively.