THE EXPRESSION OF THE PORCINE SWEET TASTE RECEPTOR IN TONGUE AND GUT TISSUES CHANGES AFTER WEANING

Sugars and artificial sweeteners are sensed by the sweet taste receptor T1R2/T1R3 present in taste buds. Recent studies in rodents showed that this receptor is also present in the gut forming part of the mucosal chemosensing system by which luminal glucose and other chemicals are sensed to trigger gut physiological responses. The aim of this study was to investigate the expression and changes during development of the porcine T1R2/T1R3 in taste and gastrointestinal tissues of pigs. Fifty-six, Pietrain x Landrance piglets were selected at birth and fed standard diets from weaning until 46 d of age. On day 0 (birth), 26 (weaning), 28 (48h after weaning), and 48 from birth, 4 piglets (2 of each sex) were sacrificed to collect tissue samples of fungiform and circumvallate papillae (TC), stomach (S), liver (L), duodenum (D), jejunum (J), and ileum (I). The relative abundance of mRNA of the pT1r2 and pT1r3 genes was quantified via real-time PCR using the tata box biding protein as housekeeping gene. Real-time data (Ct values) were analyzed using the GEE model with an exchangeable correlation structure and the GENMOD procedure of SAS. Fold change estimations (2–∆∆Ct) were performed for sex, age, tissue and their interaction relative to the liver samples from the pre-weaning group. Both genes were expressed (P<0.05) in all tissues at all ages, but the degree of expression of pT1r2 depended on the interaction between age and tissue (P<0.07). From weaning onwards, the expression of pT1r2 was upregulated (P<0.05) in TC, D, and I, but downregulated in L.In conclusion, the receptor T1R2/T1R3 is present in taste buds and gastrointestinal tract of pigs and its expression changes remarkably after weaning. tech.service.fad.com