Dissertation - Open Access
Doctor of Philosophy (PhD)
Experiments were conducted over a period of two years to study the effects of amino acid supplementation of low and high energy and low and high protein diets on the performance of SCWL laying hens. This research was conducted in two different environmental conditions; one a litter floor, cold-wall poultry house, the other a warm-wall poultry house with individual cages. In the litter floor, cold-wall environment, methionine and lysine were added singly and in combination to a 16 percent protein diet containing 1414 Calories of metabolizable energy per pound and methionine singly and a combination of methionine and lysine to a 16 percent protein diet containing 1340 Calories of metabolizable energy per pound. These were corn-soybean oil meal type diets. The dietary treatments did not beneficially affect egg-production, feed efficiency, body weight, egg weight, Haugh Units, fertility or hatchability of fertile eggs. In one experiment, the addition of 0.1 percent L-lysine did improve the Haugh Units significantly over the basal control group. With an 11 percent corn-soybean oil meal type ration containing 0.2 percent added DL-methionine the addition of 0.3 percent L-lysine slightly improved, though not significantly, egg production, feed efficiency and egg weight. Haugh Units, fertility, and hatchability of fertile eggs were not affected. Egg production and feed efficiency for the methionine plus lysine supplemented 11 percent protein diet were inferior to that obtained with the 16 percent protein diet. In addition, the low protein groups lost body weight during the experimental periods while the high protein groups gained weight. Fertility and hatchability of fertile eggs were not affected by the protein levels. In the warm-wall, individual cage environment, the effect of amino acid supplementation of low protein diets upon laying hen performance was studied. No benefit from the addition of methionine singly to a low protein, high energy diet (mostly corn) was observed. However, egg production and feed efficiency were improved with combined additions of 0.2 percent DL-methionine and 0.3 percent L-lysine to this diet. Body weight, egg weight, and Haugh Units were not affected by the amino acid additions. Egg production and feed efficiency of the methionine plus lysine supplemented 11 percent diet were inferior to that obtained from hens receiving a 16 percent protein diet containing approximately the same level of energy. This indicated that other amino acids might also be limiting in the low protein diet. Cumulative additions of methionine, lysine, glycine, valine, arginine, isoleucine, and tryptophan were made to a 10 percent protein, low energy diet containing 1001 Calories of metabolizable energy per pound. Similarly, in another experiment, methionine, lysine, tryptophan, isoleucine, arginine, and valine were cumulatively added to an 11 percent protein diet containing 1004 Calories of metabolizable energy per pound. In both of these experiments, methionine improved egg production and feed efficiency. None of the other amino acids affected the laying hen performance. The low protein groups lost body weight in both of the experiments while hens receiving a 16 percent protein diet gained weight. The low energy, low protein diets used in these experiments had a calorie-protein ratio and an amino acid make-up similar to that of the 16 percent protein diet discussed earlier. Since the addition of methionine to the low protein, low energy resulted in a response by improving egg production, a similar response might be expected from the addition of methionine to the 16 percent protein diet. However, the research results discussed earlier did not indicate such a response. Perhaps, the hens overconsumed on energy in order to meet their amino acid requirements. When amino acids were added to an 11 percent protein, high energy diet containing 0.2 percent and 0.3 percent added DL-methionine and L-lysine respectively, responses of improved egg production, feed efficiency and body weight maintenance were obtained from the addition of 0.05 percent DL-tryptophan. Egg weight and Haugh Units were not significantly affected. This indicates that, in addition to methionine and lysine, tryptophan was also limiting in the high energy, low protein diet.
Library of Congress Subject Headings
Poultry -- Feeding and feeds
Includes bibliographical references
Number of Pages
South Dakota State University
Britzman, Darwin Gene, "Studies on the Limiting Amino Acids in Laying Hen Diets" (1964). Electronic Theses and Dissertations. 2984.