Abstract
Weaning is a crucial moment in a piglet’s life. It is characterized by a generally low nutrient intake and adverse changes in the small intestinal mucosa. Proper feeding is therefore necessary to ensure normal development of the gastrointestinal tract. One substance that could provide intestinal epithelial cells with necessary energy is the amino acid glutamine. It improves epithelium structure and accelerates the growth of intestinal villi in which nutrients are absorbed, thus improving feed utilization and growth performance in piglets. The effect of glutamine on intestinal microflora also improves animal health. In addition to liver and kidneys, small intestine is the main site of glutamine metabolism, which leads to the synthesis of purine and pyrimidine nucleotides and of the important antioxidant glutathione. Glutamine is also a precursor for the synthesis of proline and arginine, the components of body proteins. Glutamine downregulates the expression of genes responsible for oxidative stress and immune activation, and increases the expression of genes that are necessary for cell growth and removal of oxidants. Due to these properties, glutamine is considered an essential amino acid in diets for weaned piglets.