Glutamine is a conditionally essential amino acid with fundamental roles in animal physiology. It acts as a primary energy source for rapidly dividing cells, including those in the gut and immune system. Beyond energy production, it is a crucial building block for proteins, nucleotides for DNA/RNA synthesis, and the potent antioxidant glutathione. During metabolic stress such as illness, trauma, or intense exercise, the body's demand for glutamine can exceed its production capacity, making dietary supplementation necessary. However, the free form of glutamine is highly unstable in solution, which limits its practical use. To address this, stable synthetic dipeptides like alanyl-glutamine have been developed to enhance glutamine's delivery, stability, and bioavailability. This review comprehensively examines the critical functions of glutamine, its distribution across different tissues, and the key challenges in its supplementation. A deeper understanding of glutamine metabolism aids in developing effective nutritional strategies to optimize its utilization, thereby supporting animal health, performance, and recovery.

To Cite This Article: Nazir U, Yang Z, Noor M, Zafar MH, Wang Z and Yang H, 2026. The vital role of glutamine in monogestric animals: more than a non-essential amino acid. Pak Vet J. http://dx.doi.org/10.29261/pakvetj/2026.006