Morphogenesis of the tongue mucosa in the domestic duck (Anas platyrhynchos f. domestica) during the late embryonic stages.

The tongue in domestic duck, as in other Anseriformes, is characterized by wide variety of shape and mechanical papillae and they fulfill different function during food collection. The present work aims to describe morphological features of the tongue as well as the pace formation of the mechanical papillae during embryonic period. The results may allow to answer whether the tongue in duck is ready to fulfill feeding function after hatching. The study revealed that the particular part of the tongue and the conical papillae of the body develop between 10th and 16th day of incubation, from the caudal part of the body into the rostral part of the tongue. The conical papillae of the lingual prominence in the first row are formed from 11th to 16th day and in the second row at the turn of the 15th and 16th day of incubation. These papillae developed symmetrically from the median part of the lingual prominence, to its edges. The lingual comb, which is used during transport of the food particles, is formed between 16th and 19th day. The present study indicated the morphological changes of the particular part of the tongue and the mechanical papillae were varied between the developmental stages. The morphology of the tongue in the domestic duck is fully developed before hatching and ready to collect food by pecking and grazing. However, filter-feeding mechanism is not still obvious.