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

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

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.

Citation

Gibbs, M., Winnig, M., Riva, I., Dunlop, N., Waller, D., Klebansky, B., Logan, D. W., Briddon, S. J., Holliday, N. D., & McGrane, S. J. (2022). Bitter taste sensitivity in domestic dogs (Canis familiaris) and its relevance to bitter deterrents of ingestion. PLoS ONE, 17(11), Article e0277607. https://doi.org/10.1371/journal.pone.0277607

• Journal Article Type: Article
• Acceptance Date: Oct 31, 2022
• Online Publication Date: Nov 30, 2022
• Publication Date: Nov 30, 2022
• Deposit Date: Jan 29, 2023
• Publicly Available Date: Jan 30, 2023
• Journal: PLOS ONE
• Electronic ISSN: 1932-6203
• Publisher: Public Library of Science
• Peer Reviewed: Peer Reviewed
• Volume: 17
• Issue: 11
• Article Number: e0277607
• DOI: https://doi.org/10.1371/journal.pone.0277607
• Keywords: Multidisciplinary
• Public URL: https://nottingham-repository.worktribe.com/output/14588462
• Publisher URL: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0277607
• Additional Information: © 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.