Intestinal Nutrient Transporter Expression in Embryonic and Posthatch Turkeys

The absorption of nutrients in the small intestine is mediated by a variety of transporter proteins, which have not been as well characterized in turkeys as in chickens. The objective of this study was to profile the mRNA expression of aminopeptidase N (APN), 7 amino acid/peptide transporters (ASCT1, b^o,+AT, CAT1, EAAT3, LAT1, y⁺LAT2, PepT1) and 3 monosaccharide transporters (GLUT2, GLUT5, SGLT1) in the small intestine of male and female turkeys pre-hatch (embryonic days 21 and 24 and day of hatch) and posthatch (day of hatch, days 7, 14, 21 and 28). Real-time PCR was used to determine mRNA abundance and data were analyzed by ANOVA using JMP Pro 11.0.  APN, b^o,+AT, PepT1, y⁺LAT2, GLUT5 and SGLT1 showed increased expression from E21 and E24 to DOH. Posthatch, all genes except GLUT2 and SGLT1 were expressed greater in females than males. GLUT2 was expressed the same in males as females and SGLT1 was expressed greater in males than females. The basolateral membrane transporters (ASCT1, CAT1, LAT1, y+LAT1, y+LAT2) were expressed greater during early development then decreased with age; while the brush border membrane transporters (EAAT3, GLUT5 and SGLT1) showed increased expression later in development. Turkeys showed high mRNA abundance of the anionic amino acid transporter EAAT3, which was 6-fold greater in the ileum of turkeys than chickens at D14. These results can be utilized to not only better formulate turkey diets to accommodate increased glutamate transport, but to also optimize nutrition for both sexes.