Ultrastructure of the intestinal canal in healthy turkeys (Meleagris gallopavo) using light and scanning electron microscopy

This study investigated the ultrastructural and histological features of the intestinal canal in healthy adult turkeys (Meleagris gallopavo) using light and scanning electron microscopy. Tissue samples from the duodenum, jejunum, ileum, and caecum were analyzed to characterize the organization of the intestinal wall. All segments exhibited the classical four-layered structure: tunica mucosa, submucosa, muscularis externa, and serosa. Significant morphological differences were identified among the intestinal segments. Villi in the duodenum showed thick, leaf-like or finger-like forms depending on location, whereas jejunal villi were thinner and elongated. Ileal villi presented a knob-like appearance, while caecal villi changed from finger-shaped at the base to leaf-shaped at the apex. Lieberkühn crypt depth and the density of Paneth cells increased from the duodenum to the ileum. Importantly, abundant lymphoid structures—including diffuse lymphoid cells, Peyer's patches, and caecal tonsils—were prominent in the lamina propria and submucosa, especially in the ileum and caecum. These findings emphasize the regional specialization of the turkey intestine for absorption and immune defense, contributing valuable reference data for future avian gastrointestinal studies and comparative histology.