Department of Histology and Embryology, Faculty of Veterinary Medicine and Animal Science, Poznan University of Life Sciences, 60-625 Poznan, Poland.
Department of Histology and Embryology, Faculty of Veterinary Medicine and Animal Science, Poznan University of Life Sciences, 60-625 Poznan, Poland.
Poult Sci. 2021 May;100(5):101038. doi: 10.1016/j.psj.2021.101038. Epub 2021 Feb 10.
Nowadays, microstructural and ultrastructural analysis of organs of the avian beak cavity points to new aspects of adaptation to food intake through the various feeding groups. These data should undoubtedly be considered in the time of mass production of compound feed in poultry, when many studies analyze the optimal size of food particles and their doses. Galliformes possess complex mechanisms of food collection and transport in the beak cavity. They collect food by pecking and transport food by using catch-and-throw and slide-and-glue mechanisms. The aim of current research is to conduct functional analysis of the tongue in poultry such as domestic turkey in context of type of food, method of food intake, and transport to the esophagus. The study involves observations of macroscopic and microscopic structures of the tongue mucosa by light microscopy and scanning electron microscopy techniques with histochemical analysis of lingual glands. The obtained results showed that the tongue in domestic turkey fills two-thirds of the beak cavity. The lingual structure responsible for pecking is a rigid plate called lingual nail that works similar to a shovel to collect food. The median groove presented on surface of the tongue indicated path of food transport. The conical papillae on border between the lingual body and root are responsible for the last stage of food transport, while the papillae on the sides of root stabilize the path of food transport. For the first time, the presence of 2 types of cornified mucosal epithelia, orthokeratinized and parakeratinized epithelium, was presented. The analysis of occurrence of complex tubular lingual glands indicates production of mucous secretions composed of neutral mucopolysaccharides, with addition of sialomucins and sulfomucins. Mucous secretions moisturize surface of the tongue, thus facilitating the transport of dry food. The presence of sulfur mucopolysaccharides responds to protective function. To sum up, the tongue in domestic turkey is adapted to collect fine or coarse ground feed in form of mash or pellets through pecking and its transport to the esophagus using the slide-and-glue and throw-and-catch mechanisms.
如今，对禽类喙腔器官的微观和超微结构分析揭示了不同取食类群适应取食方式的新方面。在禽类配合饲料大规模生产时，许多研究分析食物颗粒的最佳大小及其剂量，这些数据无疑应在此时加以考虑。鸡形目动物具有喙腔内食物采集和运输的复杂机制。它们通过啄食采集食物，通过抓-抛和滑-粘机制来运输食物。当前的研究目的是在食物类型、取食方式和向食管运输等方面，对家禽（如家鸡）的舌进行功能分析。研究包括通过光镜和扫描电子显微镜技术观察舌黏膜的宏观和微观结构，并对舌腺进行组织化学分析。研究结果表明，家鸡的舌占据喙腔的三分之二。负责啄食的舌结构是一个刚性的板状结构，称为舌甲，其作用类似于铲子，用于采集食物。舌表面的中央沟表明了食物运输的路径。舌体与舌根交界处的锥形乳突负责食物运输的最后阶段，而舌根两侧的乳突则稳定食物运输的路径。首次提出存在 2 种角蛋白黏膜上皮，即正角化上皮和不全角化上皮。对复杂管状舌腺的出现进行分析表明，分泌的黏液含有中性黏多糖，并伴有涎黏蛋白和硫黏蛋白。黏液分泌物润湿舌表面，从而有助于干燥食物的运输。硫黏多糖的存在是为了发挥保护作用。综上所述，家鸡的舌通过啄食来采集细或粗的粉状或颗粒状饲料，并通过滑-粘和抓-抛机制将其运输到食管。
