Bitter, sweet and umami taste receptors and downstream signaling effectors: Expression in embryonic and growing chicken gastrointestinal tract

Abstract

Taste perception is a crucial biological mechanism affecting food and water choices and consumption in the animal kingdom. Bitter taste perception is mediated by a G-protein-coupled receptor (GPCR) family-the taste 2 receptors (T2R)-and their downstream proteins, whereas sweet and umami tastes are mediated by the GPCR family -taste 1 receptors (T1R) and their downstream proteins. Taste receptors and their downstream proteins have been identified in extra-gustatory tissues in mammals, such as the lungs and gastrointestinal tract (GIT), and their GIT activation has been linked with different metabolic and endocrinic pathways in the GIT. The chicken genome contains three bitter taste receptors termed ggTas2r1, ggTas2r2, and ggTas2r7, and the sweet/umami receptors ggTas1r1 and ggTas1r3, but it lacks the sweet receptor ggTas1r2. The aim of this study was to identify and determine the expression of genes related to taste perception in the chicken GIT, both at the embryonic stage and in growing chickens. The results of this study demonstrate for the first time, using real-time PCR, expression of the chicken taste receptor genes ggTas2r1, ggTas2r2, ggTas2r7, ggTas1r1, and ggTas1r3 and of their downstream protein-encoding genes TRPM5, α-gustducin, and PLCβ2 in both gustatory tissues-the palate and tongue, and extra-gustatory tissues-the proventriculus, duodenum, jejunum, ileum, cecum, and colon of embryonic day 19 (E19) and growing (21 d old) chickens. Expression of these genes suggests the involvement of taste pathways for sensing carbohydrates, amino acids and bitter compounds in the chicken GIT.

Effects of chronic heat exposure on growth performance, intestinal epithelial histology, appetite‐related hormones and genes expression in broilers

“…Umami taste receptors ( T1R1 and T1R3 ) are expressed in gut enteroendocrine cells and contribute to nutrient sensing, absorption and hormone releasing . In chickens, nutrient‐sensing receptors of T1R1 and T1R3 are mainly responsible for l ‐amino acid sensing, and the solo T1R3 can also serve as a monosaccharide taste sensation .…”

“…Umami taste receptors (T1R1 and T1R3) are expressed in gut enteroendocrine cells and contribute to nutrient sensing, absorption and hormone releasing. 40,41 In chickens, nutrient-sensing receptors of T1R1 and T1R3 are mainly responsible for L-amino acid sensing, and the solo T1R3 can also serve as a monosaccharide taste sensation. 42 The BCAAs, including Val, Leu and Ile as essential amino acids, are involved in several important functions, such as regulation of nutrient metabolism and as neurotransmitters.…”

Sensor Devices Inspired by the Five Senses: A Review

“…The aforementioned receptors share the gustducin G‐protein but follow a transduction pathway triggered by the β and γ G gust subunits. The βγ complex activates the effector PLC Cβ2 (PLCβ2) which in turn converts the membrane lipid phosphatidylinositol 4,5‐bisphosphate (PIP 2 ) into IP 3 and DAG 2 nd messenger molecules . IP 3 in particular can bind to receptors which open intracellular Ca 2+ stores, which in turn propagate the opening of so‐called store‐operated channels .…”

Expressions of multiple umami taste receptors in oral and gastrointestinal tissues, and umami taste synergism in chickens

“…Sawamura et al revealed that a chicken fatty acid receptor candidate, GPR120 (G-protein-coupled receptor 120), cloned from chicken oral tissue, responded to fatty acids [14]. With respect to the sense of umami taste in chickens, one of the umami taste receptors, the T1R1/T1R3 heterodimer, was expressed in the oral and gastrointestinal tract tissues in chickens [15] and was activated by L-alanine and L-serine [16]. In another study, we revealed that primary culture cells from isolated taste buds from the chicken palate responded to a mixture of MPG and IMP [17].…”