Effect of age and of maternal antibiotic treatment on offspring gastric expression of the receptor for umami taste (TAS1R1) and of α-transducin, a taste receptor signaling messenger

International audience; Gut maturation during suckling and after weaning is influenced by maternal environment. Scarce is the knowledge on the presence and the regulation of taste receptors in the pig gastro-intestinal tract. The same is for the machinery that processes the taste signals, including α-transducin. Our main goal was to assess if the age of offspring and maternal environment, as influenced by a maternal antibiotic treatment, could affect the expression of the receptors for umami and sweet taste in offspring stomach. Eighty 4 pigs reared from sows fed a diet with or without Amoxicillin (40 mg/kg BW/d, on −10 d to +21 d from farrowing, ATB) were sacrificed at 14 d, 21 d, 28 d (weaning) or 42 d, and sampled for oxyntic (OXY) and pyloric mucosa (PY). In PY, gene expression (RT Real-Time PCR, corrected for 2 housekeeping genes) for TAS1R3 (necessary for sweet and umami taste) was stable in time and not affected by ATB. TAS1R1 (complementary for umami) increased from suckling to post-weaning period (P = 0.001), and was lower in ATB offspring (P = 0.013). TAS1R2 (complementary for sweet) gene expression was not detected. TAS1R1 gene expression in OXY, increased with age in suckling period (P = 0.013), but not later. Transducin gene expression in PY was higher in ATB offspring (P = 0.043); the number of cells staining for transducin per gland in PY decreased during the suckling and post-weaning periods (P < 0.001), while cell counts tended to be lower in ATB offspring (P =0.092). TAS1R1 and TAS1R3 gene expression in PY was also tested in littermate offspring that were reared up to the age of 5 mo, and then kept on the same diet (low fat, 2%) or switched to a high fat (11%) diet for 4 weeks (n = 10 pigs per group). Neither perinatal ATB treatment nor later fat diet content affected the studied variables. Data show that sensing for umami taste has relevance for 2 different gastric mucosae. It can change with age and be potentially affected by maternal environment. For α-transducin, divergent observations on gene expression and positive cell counts require further evaluation.