Bitter taste sensitivity in domestic dogs (Canis familiaris) and its relevance to bitter deterrents of ingestion

Matthew Gibbs; Marcel Winnig; Irene Riva; Nicola Dunlop; Daniel Waller; Boris Klebansky; Darren W Logan; Stephen J Briddon; Nicholas D Holliday; Scott J McGrane

doi:10.1371/journal.pone.0277607

Bitter taste sensitivity in domestic dogs (Canis familiaris) and its relevance to bitter deterrents of ingestion

PLoS One. 2022 Nov 30;17(11):e0277607. doi: 10.1371/journal.pone.0277607. eCollection 2022.

Authors

Affiliations

¹ Waltham Petcare Science Institute, Waltham on the Wolds, Melton Mowbray, Leicestershire, United Kingdom.
² School of Life Sciences, The Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom.
³ AXXAM GmbH, Constance, Germany.
⁴ AXXAM SpA, IMAX Discovery Unit, Bresso, Milan, Italy.
⁵ BioPredict, Inc., Demarest, NJ, United States of America.

Abstract

As the most favoured animal companion of humans, dogs occupy a unique place in society. Understanding the senses of the dog can bring benefits to both the dogs themselves and their owners. In the case of bitter taste, research may provide useful information on sensitivity to, and acceptance of, diets containing bitter tasting materials. It may also help to protect dogs from the accidental ingestion of toxic substances, as in some instances bitter tasting additives are used as deterrents to ingestion. In this study we examined the receptive range of dog bitter taste receptors (Tas2rs). We found that orthologous dog and human receptors do not always share the same receptive ranges using in vitro assays. One bitter chemical often used as a deterrent, denatonium benzoate, is only moderately active against dTas2r4, and is almost completely inactive against other dog Tas2rs, including dTas2r10, a highly sensitive receptor in humans. We substituted amino acids to create chimeric dog-human versions of the Tas2r10 receptor and found the ECL2 region partly determined denatonium sensitivity. We further confirmed the reduced sensitivity of dogs to this compound in vivo. A concentration of 100μM (44.7ppm) denatonium benzoate was effective as a deterrent to dog ingestion in a two-bottle choice test indicating higher concentrations may increase efficacy for dogs. These data can inform the choice and concentration of bitter deterrents added to toxic substances to help reduce the occurrence of accidental dog poisonings.

Copyright: © 2022 Gibbs et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Dogs
Eating
Humans
Sensation
Taste Buds*
Taste*

Substances

denatonium

Grants and funding

All work in the manuscript was funded by Mars Petcare UK. We declare that M.G., N.D., D.W., D.W.L., and S.J.M. are all employees of Mars Petcare UK. M.G. contributed to the conception and design of the work, the acquisition, analysis, and interpretation of the data, and drafted and substantially revised the work. N.D. contributed to the acquisition, analysis, and interpretation of the data for the in vivo work and revised the draft of the work. D.W. contributed to the analysis and interpretation of the data for the in vivo work and revised the draft of the work. D.W.L. contributed to the conception, experimental design and substantially revised the work. S.J.M. contributed to the conception, experimental design, interpretation of the data for the in vitro and in vivo work, and substantially revised the work. The funder approved the study design, data collection and analysis, decision to publish, and preparation of the manuscript.