Unlike mammals, birds have a reduced retention time of food in the oral cavity, lack of taste buds on the tongue, and have limited saliva secretion, which initially underestimated the relevance of their taste system.
Recent studies, driven by the genomic era, have shown that the taste system in birds is as crucial as in mammals, albeit with fundamental differences in anatomy, taste bud distribution and molecular structure of taste receptors.
In birds, the taste buds are distributed over the upper palate, the sublingual area and the pharynx, where the taste perception takes place, while the tongue has a feed gathering and swallowing function. According to swallowing patterns, the taste buds vary in size, structure and location depending on the diet and ecological adaptations of each species.
The family 1 taste receptors (T1R1 and T1R3) of birds mediate the taste of amino acids and sugars, this is, umami and sweet taste in humans, respectively. Dietary amino acids are essential for all avian species, with the T1R1-T1R3 receptor playing a key role in detecting them across diverse feeding styles. This receptor, common to vertebrates, likely helps birds identify amino acid-rich foods.
Poultry, like mammals, also have umami and sweet taste receptors in the gastrointestinal tract that are involved in the regulation of the appetite-satiety cycle. Nutrients from the intestine activate enteroendocrine cells that secrete intestinal peptides, which in turn activate the vagus nerve, transmitting the nutritional status of the bird to the brain.
