Two experiments were conducted with a total of 1,728 Large White turkeys to determine the relative potencies of four methionine compounds on an equimolar basis. A 28% protein basal diet composed primarily of ground yellow corn, dehulled soybean meal, and meat and bone meal was supplemented with DL-methionine (DL), sodium salt of DL-methionine (MENA), methionine hydroxy analogue calcium salt (MHAC), or methionine hydroxy analogue free acid (MHAA) at the .06, .12, .18, .24, or .3090 level of added methionine. Each of these 20 diets was fed to two pens of poults of each sex (9 birds per pen), and the basal diet was fed to eight pens of each sex from one day to sevenweeks of age in each experiment.

From the combined six-week body weight data, MENA was 104.7 (86.1, 123.3), MHAC 101.8 (83.5, 120.1), and MHAA 92.590 (74.9, 110.1) as potent as DL (with 9590 fiducial limits) by the slope ratio procedure. No differences were detectable among the methionine products. The extra one degree of freedom associated with the nonlinear procedure accounted for 4.8 and 10. 7% of the residual variation in Experiments 1 and 2, respectively. Relative potencies were obtained for MENA of 110.3 and 115.6, MHAC of 100.4 and 88.1, and MHAA of 89.7 and 112.390 in Experiments 1 and 2, respectively.

Two additional experiments were conducted using a total of 1,680 poults to study the relationships of methionine, choline, and sulfate in practical-type diets. A 6 x 2 x 2 factorial design was used involving increments of .0690 DL-methionine from 0 to .3090, 0 or .20% choline chloride, and 0 or . 10% potassium sulfate. The variables were added to a 21 90 protein basal diet containing 61% ground yellow corn and 32% dehulled soybean meal to which no supplemental choline or sulfate was added. Each of the 24 diets was fed to two pens of medium-type turkeys of each sex (9 birds per pen) from four to eight-weeks of age in the first experiment, and to two pens of Large White turkeys of each sex (9 and 8 birds per pen for males and females, respectively) from three to seven-weeks of age in the second experiment.

From the addition of .06% and .12% DL-methionine, body weight gains were increased 11.0 and 16.5% in the first experiment, and 8.9 and 13.690 in the second experiment, respectively. In addition, methionine increased feed consumption about 1/3 these amounts, and feed efficiencies 1/2 these amounts. The addition of choline or sulfate failed to significantly increase these parameters, even in the absence of methionine. No significant interactions were observed among the dietary variables in either experiment.