Niknafs Shahram, Navarro Marta, Schneider Eve R, Roura Eugeni
Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD, Australia.
Department of Biology, University of Kentucky, Lexington, KY, United States.
Front Physiol. 2023 Sep 8;14:1235377. doi: 10.3389/fphys.2023.1235377. eCollection 2023.
Taste or gustation is the sense evolving from the chemo-sensory system present in the oral cavity of avian species, which evolved to evaluate the nutritional value of foods by detecting relevant compounds including amino acids and peptides, carbohydrates, lipids, calcium, salts, and toxic or anti-nutritional compounds. In birds compared to mammals, due to the relatively low retention time of food in the oral cavity, the lack of taste papillae in the tongue, and an extremely limited secretion of saliva, the relevance of the avian taste system has been historically undermined. However, in recent years, novel data has emerged, facilitated partially by the advent of the genomic era, evidencing that the taste system is as crucial to avian species as is to mammals. Despite many similarities, there are also fundamental differences between avian and mammalian taste systems in terms of anatomy, distribution of taste buds, and the nature and molecular structure of taste receptors. Generally, birds have smaller oral cavities and a lower number of taste buds compared to mammals, and their distribution in the oral cavity appears to follow the swallowing pattern of foods. In addition, differences between bird species in the size, structure and distribution of taste buds seem to be associated with diet type and other ecological adaptations. Birds also seem to have a smaller repertoire of bitter taste receptors (T2Rs) and lack some taste receptors such as the T1R2 involved in sweet taste perception. This has opened new areas of research focusing on taste perception mechanisms independent of GPCR taste receptors and the discovery of evolutionary shifts in the molecular function of taste receptors adapting to ecological niches in birds. For example, recent discoveries have shown that the amino acid taste receptor dimer T1R1-T1R3 have mutated to sense simple sugars in almost half of the living bird species, or SGLT1 has been proposed as a part of a T1R2-independent sweet taste sensing in chicken. The aim of this review is to present the scientific data known to date related to the avian taste system across species and its impact on dietary choices including domestic and wild species.
味觉或味觉感受是从鸟类口腔中存在的化学感应系统进化而来的一种感觉，该系统通过检测包括氨基酸和肽、碳水化合物、脂质、钙、盐以及有毒或抗营养化合物在内的相关化合物来评估食物的营养价值。与哺乳动物相比，鸟类由于食物在口腔中的停留时间相对较短、舌头上缺乏味蕾且唾液分泌极其有限，其味觉系统的相关性在历史上一直被低估。然而，近年来，部分由于基因组时代的到来，出现了新的数据，证明味觉系统对鸟类和哺乳动物一样至关重要。尽管有许多相似之处，但鸟类和哺乳动物的味觉系统在解剖结构、味蕾分布以及味觉受体的性质和分子结构方面也存在根本差异。一般来说，与哺乳动物相比，鸟类的口腔较小，味蕾数量较少，并且它们在口腔中的分布似乎遵循食物的吞咽模式。此外，鸟类物种之间味蕾的大小、结构和分布差异似乎与饮食类型和其他生态适应性有关。鸟类似乎也有较少种类的苦味受体（T2Rs），并且缺乏一些味觉受体，如参与甜味感知的T1R2。这开辟了新的研究领域，重点关注独立于GPCR味觉受体的味觉感知机制以及发现适应鸟类生态位的味觉受体分子功能的进化转变。例如，最近的发现表明，在几乎一半的现存鸟类物种中，氨基酸味觉受体二聚体T1R1 - T1R3已经发生突变以感知单糖，或者有人提出SGLT1是鸡中独立于T1R2的甜味感知的一部分。这篇综述的目的是展示迄今为止已知的与跨物种鸟类味觉系统相关的科学数据及其对包括家养和野生鸟类在内的饮食选择的影响。
