A Study on the Morphology, Histochemistry and Histology comparison of the gastrointestinal tract of Alburnus chalcoides of the Caspian Sea during the Larval, Infant and Premature Periods

Alburnus chalcoides is a member of the Cyprinidae that a few studies have done on its internal organs. Considering the importance of the gastrointestinal tract on the growth and survival of animals, it has been examined in this study. Sampling of the fishes was taken randomly from the first day after hatching to pre-puberty at different intervals. In fact, the growth of this fish was assessed through morphological and histological study using Hematoxylin-Eosin staining method and the secretion of the gastrointestinal mucosal layers of the gastrointestinal tract in terms of the carbohydrates was carried out by histological procedure by staining the Periodic acid Schiff (PAS). Anatomical study on this fish showed that its digestive system consists of two major parts of the, esophagus and intestine. In the early days, gastrointestinal tract was a simple and primary tube, in which no mucosal secretion activity was observed however this activity began after the appearance of Goblet cell and a layer of neutral polysaccharide compounds was observed on the gastrointestinal tract. The presence of neutral polysaccharides in the gastrointestinal mucosa showed its role in digestion and absorption of food, and it is important to protect the epithelial layer of the digestive tract and food passage. The evolutionary features of this fish are somewhat similar to other fish of Cyprinidae, but specific differences are also evident in this species.