Comparative Histological Analysis of the Parotid and Submandibular Glands in Ovine and Caprine Species Using Histochemical, Immunohistochemical, and Stereological Methods

This work was designed to compare the histochemical, immunohistochemical, and stereological features of the parotid and mandibular glands of sheep and goat as representative for ovine and caprine species. The parotid gland was serous in both species, while the mandibular gland was a mixed one. Mucous acini were Periodic Acid-Schiff positive and Aldehyde Fuchsin (AF) negative. Serous acini were AF positive. The parotid gland of goat was significantly larger than that of sheep; however, the mandibular gland of sheep was significantly larger than that of goat. The volume of isolated serous acini in the mandibular gland of goat was significantly higher than that of sheep. The total length of ductal system was nonsignificant in both species, but the total volume of parotid glands' ducts was significantly higher than those of mandibular glands. The parotid glands were negative for Mucin-1; however, the mandibular glands were moderately positive. Cytokeratin 7 exhibited a pronounced expression within the ductal systems of both glands. S100 proteins were expressed intensely by serous acini of glands in sheep; however, its expression was confined to the intercalated ducts and myoepithelial cells in goat. The obtained results suggest that the feeding modalities may lead to significant variations in histological and histophysiological characteristics.