Seventy day safety assessment of an orally ingested, l-glutamine-containing oat and yeast supplement for horses

We describe a safety assessment of an oral supplement designed to nutritionally support the gastrointestinal system of horses. The supplement comprised a mixture of essential (l-threonine) and conditionally essential (l-glutamine) amino acids, polar lipids, oat bran rich in beta glucans and yeast extract. Young (1-2 years) horses of both sexes were allocated to control (n = 7) and treatment groups (n = 7) and studied for 9 weeks. Horses in the treatment group received the supplement daily for 8 weeks. After 8 weeks of supplementation, horses were studied for one additional week. Outcome measures included body mass, weight gain, results of clinical examination, hematology and plasma chemistry. There were no adverse events associated with supplementation and horses in both groups showed normal weight gain, clinical signs, hematology and chemistry. l-Glutamine, which is not yet listed as GRAS, was considered with respect to its potential for nutritional support and safety when ingested orally. It is concluded that this oral supplement, when ingested by horses at twice the recommended daily level, was safe and does not pose a health risk when used in accordance with good feeding practice.