Histology of the digestive tract of the steno-endemic Cobitis herzegoviniensis (Teleostei: cobitidae) from Mostarsko blato (Neretva river basin, Bosnia and Herzegovina)

The study of endemic fish species is of great importance, considering that extensive knowledge is a prerequisite for adequate protection and conservation. This study investigated the histology of the digestive tract of the steno-endemic fish Cobitis herzegoviniensis Buj & Šanda 2014, from Mostarsko Blato (Neretva River basin, Bosnia and Herzegovina). Histology of the digestive tract of this species was investigated, since there is a scarcity of information regarding its digestive biology. Specimens (average total length 78 mm, average standard length 69 mm, mean weight 3,836 g) of the species C. herzegoviniensis were caught in the lower course of the Lištica River in the area of Mostarsko Blato in June 2019. The tissue of selected organs of the digestive system was used as the basic material. Using basic histological techniques, microscopic preparations were made from the tissue. This species has only esophagus and intestine. When studying the microscopic structure of the wall of the digestive tract, it was determined that the wall consists of three layers: mucosa (tunica mucosa), muscular layer (tunica muscularis) and outer layer (tunica serosa). The basic building block of the liver is the liver cell or hepatocyte.