Food preference and olfactory discrimination tests: A complementary approach to understand the drivers of hedonic responses in dogs

Understanding the food preference of animals remains a challenge in sensory science. Here, a complementary approach combining food preference and food odor discrimination tests was applied to dogs as consumers. This approach was designed to distinguish a lack of preferential choice from a lack of discrimination in dogs. Consumption of four pet food products by a taster dog panel was evaluated. First choice and intake ratio results were strongly linked, suggesting that odor perception influenced the dogs' food consumption. Within this test, two products were preferred by the dogs and favored equally. To provide more depth to the interpretation, we used an olfactometer to measure the dogs' discrimination of the four product odors. A panel of dogs, designated the expert panel, was specially trained in olfactory recognition of one of the two equally preferred products. The main results demonstrated that dogs can discriminate products by olfaction and express the same food preference for different products, even if they have different odors. Moreover, the olfactory experiments allowed us to conclude that the differences in intensity among odors did not affect their discrimination. Practical applications The combination of a two-bowl consumption test and an olfactory discrimination task using a dual-port olfactometer appears to be a complementary approach that could help clarify the drivers of animals' liking. In dogs, for example, olfaction is thought to play a major role in food preference. Therefore, using an automated olfactometer technique provides an opportunity to control and modulate the odors presented to the animal and further explore the role of olfaction in the discrimination of different odorants. Thus, the proposed method could be useful to measure the influence of odor on dogs' food selection and to discern a real absence of preference from a lack of olfactory discrimination capacity, which is currently an important methodological obstacle to analyzing the results of two-bowl consumption tests. In addition, this complementary approach could be transferred to further works dealing with the understanding of food preference mechanisms in other species.