Glutamine and its derivatives e.g., alpha-ketoglutaric acid (AKG) or ornithine- alpha-ketoglutarate (OKG) are molecules with a central role (via the Krebs cycle) in systemic, intestinal and gut bacterial metabolism. Studies have shown that AKG is a precursor not only of glutamine and arginine, but also of some other keto acids e.g., alpha-ketoisocaproate which in turn is a precursor of hydroxy-methyl-butyrate, which itself is regarded as a protein catabolic protector. Recently it has been postulated that AKG is not only an important energy donor, but that it also functions as an ammonium ion scavenger via transformation to glutamate, ornithine and putrescine and finally to GABA or succinate. Several beneficial effects of AKG have been reported in human medicine e.g., improved patients' recovery following gastrointestinal surgery. On the other hand, is was reported that 100 per cent glutamate metabolism in the first pass in infant pigs' small intestine. In the current presentation we discuss the potential benefits of using glutamine derivatives in human clinical nutrition as well as their role as feed additives in the production of farm animals.