Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Richard C. Wahlstrom


It has long been established that lysine is the first limiting amino acid in cereal based diets for growing pigs. Some studies have shown that corn is first limiting in tryptophan for growing pigs while other studies indicate that lysine and tryptophan are equally limiting. Soybean meal is usually added to corn diets to supply the lysine required but in some countries where soybean meal is not easily available, fish and meat meals are the common protein supplements. In the developing countries, soybean meal, fish meal and meat meal are not only in short supply but also very expensive. Lysine is thus a major problem as the first limiting amino acid. Other sources of supplemental lysine such as synthetic lysine and ways of improving ·lysine utilization in the growing pig would therefore be desirable. There are many factors affecting the utilization of lysine and other amino acids in pigs. Some of these factors are heat during feed processing, method of processing, the crude protein level in the diet, the caloric density (energy level) of the diet, the balance of essential amino acids, the source and biological availability of the amino acids, physiological stage of the animal, frequency of feeding and the electrolyte balance in the diet. Cations such as sodium and potassium have been shown to affect lysine and protein metabolism in nonruminants. The effects of potassium varies in different species. In the chicken, potassium supplementation to an imbalanced diet, improves performance by alleviating lysine-arginine antagonisms. In rats, potassium deficiency has been found to raise the concentrations of lysine, arginine and histidine in the kidneys and muscles. Potassium supplementation to rat diets lowers the amino acid concentration of the tissues. It has therefore been proposed that in cases of potassium deficiency, the basic amino acids enter the cells by diffusion, due to electrostatic force, in order to maintain the cation-anion balance. In cases of kwashiorkor, a tropical malnutritional condition in children, protein deficiency has been associated with low plasma potassium concentrations. Potassium supplementation to the diets of kwashiorkor children has alleviated and cured the disease. In pigs, potassium supplementation to low lysine or low protein diets has been found to improve growth performance. Except for the ameliorating effects of potassium, there is no need for potassium supplementation in swine diets since most feedstuffs contain amounts of potassium that exceed the requirements for all classes of pigs. The thesis reported herein is that potassium supplementation in weanling pig diets improves performance through the efficient utilization of lysine. The experiments were conducted to determine the response of weanling pigs to potassium supplementation at two levels of dietary lysine. The effects of potassium on plasma lysine and potassium was also determined.

Library of Congress Subject Headings

Lysine in animal nutrition
Swine -- Feeding and feeds



Number of Pages



South Dakota State University