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Splanchnic extraction of phenylalanine in mature mares was not affected by threonine supplementation
- Mastellar, S.L., Barnes, T., Cybulak, K., Urschel, K.L.
- The veterinary journal 2016 v.207 pp. 190-192
- Thoroughbred, dietary supplements, glutamic acid, intravenous injection, mares, oxidation, phenylalanine, sodium bicarbonate, threonine
- This study determined splanchnic extraction of phenylalanine at two intakes of threonine. Six Thoroughbred mares were supplemented with isonitrogenous amounts of either threonine or glutamate. Dietary threonine intakes were 119 (+Thr) and 58 (Basal) mg/kg/day, respectively. Each horse received each diet twice and each was studied once with an oral and once with an intravenous (IV) infusion of [1-13C]phenylalanine. A 2-h primed, constant IV infusion of [13C]sodium bicarbonate and a 4-h primed, constant infusion of [1-13C]phenylalanine, either orally or IV, were used to measure isotopic enrichments. Phenylalanine kinetics were not affected by diet (P > 0.05). Values for the splanchnic extraction of phenylalanine were 26 ± 5% and 27 ± 3% for the +Thr and Basal supplemented diets, respectively. These values will improve the accuracy of future equine indicator amino acid oxidation studies.