Digestive tract and enzymes development in early life stages of marble goby (Oxyeleotris marmoratus Bleeker)

Abstract

A study on the development of the digestive system of marble goby (Oxyeleotris marmoratus) larvae was conducted from hatching until 35 days after hatching (DAH) by histological and histochemical techniques. At hatching, the digestive system appear as a straight undifferentiated tube, with a small lumen and the mouth and anus still not open. During the endogenous feeding phase (0-3 DAH), yolk was absorption while the gut differentiated into a buccal cavity, oesophagus and intestine. The liver appeared as compact basophilic tissue and situated between the yolk sac and the developing gut without any vacuoles. The epithelium of the intestine started to fold on 2 DAH. The rectum was separated from the anterior intestine by the ileorectal valve. Lipid vacuoles were observed in the rectum on 3 DAH and in small intestine on 7 DAH. At onset of exogenous feeding (4-5 DAH), the digestive tract was divided into 5 parts: buccopharynx, oesophagus, stomach, intestine and rectum.