Title: An Investigation Concerning the Possibility of Replacing Supplemental Methionine with Choline in Practical Laying Rations
Abstract:Three experiments were conducted to determine the possibility of replacing supplemental methionine with choline in practical laying rations. Two basal diets containing 16.4 and 14.4% protein were used...Three experiments were conducted to determine the possibility of replacing supplemental methionine with choline in practical laying rations. Two basal diets containing 16.4 and 14.4% protein were used in these experiments. The calculated levels of methionine and total sulfur amino acids (TSAA) were, respectively, .29 and .52% in the high protein and .26 and .45% in the low protein basal rations. The experimental rations were obtained by adding methionine, choline, or their combinations to the basal rations. Hens received the experimental rations for periods of 10, 20, and 40 weeks for the first, second, and third experiments, respectively. Supplemental methionine, choline, or their combinations did not have a significant effect on production traits with either levels of protein in the first experiment. In the second experiment, production traits were not improved by adding methionine or choline to the 16.4% basal diet. However, a significant egg production response was obtained by adding methionine, choline, or their combinations to the 14.4% protein diet. Egg size was significantly increased by methionine, whereas combinations of methionine and choline tended to increase egg size with the 14.4% protein diet. Adding choline alone to this basal diet did not affect egg size. In the third experiment, egg production of birds fed basal diets supplemented with methionine or choline was similar. However, with either level of protein, birds that received methionine-supplemented diets produced significantly larger eggs than those receiving choline-supplemented diets. The results of these experiments generally suggested that when practical laying rations are deficient in methionine and TSAA, choline supplementation may improve egg production. However, under such conditions choline in contrast to methionine is not effective in increasing egg size.Read More