Histological and histochemical study of the duodenum of the plains viscacha (Lagostomus maximus) at different stages of its ontogenetic development

The general objective of this study focused on the duodenal histological and histochemical analysis of fetuses and adults of plains viscacha (Lagostomus maximus) from the Buenos Aires province (Argentina). Histological techniques, histochemical procedures for localizing and characterizing glycoproteins (GPs) and lectin histochemical techniques for the identification of specific sugar residues were used. The duodenal structure of all age groups here considered was typical of mammals. We identified a proliferation phase and an epithelial morphogenesis in mid‐gestational fetuses, an intermediate period of cell differentiation in at‐term fetuses and a posterior stage of physiological maturation in adults. According to histochemistry, the diverse GPs elaborated and secreted into the duodenum show a high degree of histochemical complexity related to the multiple functions of mucus in the digestive tract. The GPs in the duodenum of L. maximus and their glycosylation patterns varied according to the animal's age and the developmental state of the organ.