Glucose and cationic amino acid transporter expression in growing chickens ( Gallus gallus domesticus)

Abstract

Tissue glucose transporter (GLUT1–3) and cationic amino acid transporter (CAT1–3) mRNA expression was determined in growing broiler chicks posthatch. In two experiments, tissues were either collected on days 1, 3 and 7 or days 1 and 14 posthatch. Heart and liver were the only tissues expressing a GLUT isoform on day 1. All tissues expressed a GLUT isoform on day 7 except for the thymus. Most tissues expressing a CAT isoform on day 1 decreased mRNA levels through day 7 ( P<0.05), except for bursa CAT-1 which tended to increase ( P=0.05). The thymus and spleen did not express any CAT isoform mRNA until day 7. The liver was the only tissue expressing GLUT-2 mRNA through day 14. On day 14, GLUT-1, CAT-1 and CAT-2 mRNA were differentially expressed across tissues ( P<0.05). High-affinity GLUT and CAT mRNA expression was highest in the heart and bursa, respectively ( P<0.05). Total CAT mRNA expression was greatest in the bursa ( P<0.05). The thymus had the lowest high affinity GLUT and total CAT mRNA expression on day 14 posthatch. Therefore, T lymphocytes within the thymus may be most susceptible to glucose and cationic amino acid supply.