Morphology of the major salivary glands of Spix's Yellow-Toothed Cavys (Galea spixii Wagler, 1831)

Rodents can present a large number of morphophysiological variations of the digestive system, allowing them to feed on different diets. In this context, the objective was to describe the morphology of the major salivary glands of Galea spixii. Gross dissection, light microscopy and transmission and scanning electron microscopy assessments of 12 specimens were carried out. The results demonstrate that the G. spixii has four pairs of major salivary glands (parotid, mandibular, zygomatic and sublingual). The glands are lobulated, composed acinar, consisting of mucous and serous acini, with the predominant parotid gland being serous and the zygomatic gland mucous. The mandibular and sublingual glands are mixed. The glands secrete acidic and neutral mucins and commonly present intercalary, striated and excretory ducts. The ultrastructure of the acinar cells suggests the presence of great cellular activity, with a cytoplasm taken by a rough endoplasmic reticulum, many mitochondria, vesicles of electrolucent nature and dispersed chromatin. In conclusion, the major salivary glands of G. spixii are constituted of mucous and serous acini, with serous acini predominant in the mandibular areas. The data also suggest that these rodents may adopt different types of diets, which may explain their adaptability to semi-arid environments.