Is the pig a good umami sensing model for humans? A comparative taste receptor study

Abstract

The diversity of taste perception across species reflects a dietary adaptation to different ecological niches. Laboratory rodents have been widely used as models for human nutritional studies including the understanding of peripheral chemosensing. Nevertheless the diet type as well as the anatomical and functional features of bigger mammals such as the pig may merit further consideration as models for humans. Recently, the porcine umami taste receptor pTas1r1/ pTas1r3 and porcine mGluR4 gene sequences have become available. The aim of this study was to compare the umami sensing biology with emphasis in T1R1 sequences, Venus flytrap (VFT) ligand binding domains and L-amino acid agonists of several mammalian species including human, pig and laboratory rodents. Compared to their corresponding human gene orthologues, receptor homologies where highest for the dog (T1r1 and T1r3) and the pig (mGluR4) and lowest for the mouse (T1r1, T1r3 and mGluR4). Th human T1R1 VFT domain contains 10 different amino acid residues critically involved in ligand binding. All 10 amino acid residues are conserved, both in terms of type and location, within the pig VFT domain. In turn, the arginine and histidine (both charged polar) residues at key positions 307 and 308 appear as threonine and tyrosine (both neutral polar) residues in mouse and rat sequences. Comparison of derived molecular models seems to offer a good explanation regarding the differences of in vivo preference data for L-amino acids in rats, pigs and humans. Overall, the umami sensing in pigs show higher similarity to that in humans than the umami sensing in laboratory rodents.

Recent Advances in Understanding Amino Acid Sensing Mechanisms that Regulate mTORC1

“…Owing to the species-specificity, T1R1/T1R3 in different animals can sense different AAs. Murine T1R1/T1R3 can sense up to 18 AAs [83]; human T1R1/T1R3 can sense only glutmate and aspartate [89]; while swine T1R1/T1R3 can sense at most 6 AAs, including glutmate, aspartate, alanine, glutamine, serine and threonine [90]. …”

Critical review evaluating the pig as a model for human nutritional physiology

“…However, the differences between rodents and humans in dietary habits, digestive strategies including coprophagy, nutrient requirements and nutrientnutrient interactions suggest the pig may be a closer match than rodents for studying physiological functions relating to these research areas (1)(2)(3)(4) . However, the differences between rodents and humans in dietary habits, digestive strategies including coprophagy, nutrient requirements and nutrientnutrient interactions suggest the pig may be a closer match than rodents for studying physiological functions relating to these research areas (1)(2)(3)(4) .…”

Attractants for wild pigs: current use, availability, needs, and future potential

“…Sense of taste The gustatory system of pigs is also well developed Roura et al 2011;Roura et al 2016). Similar to their extraordinary sense of smell, their sense of taste is thought to be the most developed of all mammals, including humans, due to high numbers of taste buds (Bradley 1971;Chamorro et al 1993).…”

“…Pigs have also shown preference for umami flavors, including monosodium-glutamate (MSG) and similar chemicals, guanosine-5′-monophosphate and inosine-5′-monophosphate Hellekant and Danilova 1999). It has also been suggested that adding cheesy, fruity, meaty, and sweet flavors to foodstuffs may increase consumption and palatability by young pigs (McLaughlin et al 1983;Roura et al 2011).…”